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Archive for the 'GPS' Category

Free Tools For Garmin Custom Garmin Vector Maps XIX: TypWiz, The Best TYP File Editor

I’ve done a long series of posts on this site about various tools you can use for creating custom vector maps for Garmin GPS units, one of the most powerful features for these models (even if Garmin itself doesn’t directly support it). One especially powerful feature is the capability to create your own custom point, line and area symbols for these units, either replacing Garmin’s default symbology or creating new types for use in your own map. It’s not a trivial process, and while I’ve covered a number of tools that help somewhat with creating custom symbology here and here, all of them have been lacking a bit in functionality and ease of use. But I’ve now dumped all of them in favor of a new tool I’ve found: TypWiz. You’ll still need to learn something about what TYP files are and how to use them, but TypWiz dramatically lowers the difficulty barrier for creating and editing them.

  • Loads in existing TYP files for editing, in either text or compiled TYP format
  • Saves TYP files in either text or compiled TYP format (latter requires cgpsmapper to be installed on your system)
  • Creates point, line and polygon symbology, with complete control over type and subtype, draworder
  • Easy-to-use graphic symbology editor


  • Optionally converts your selected colors into the nearest 8-bit color equivalents for older Garmin models, i.e. the previous OS used in the 60C and color eTrex models. Newer models use a wider 16-bit color range.
  • Code section shows TYP file text code for that symbol; changes in the graphic editor show up automatically in the code section, and vice versa.
  • You can also save graphics from the editor as bitmap files, for use as custom POI icons or custom waypoints on compatible Garmin units. Note that these are saved in 24-bit BMP format; older units require 8-bit BMP files with 96-dpi resolution.
  • Short but very clear program manual.

You should also poke around the main OSM Tools site, home of TypWiz, as there are a bunch of additional utilities worth checking out:

  • MapSource Uploader – A program to help install OSM-based Garmin maps into MapSource/BaseCamp.
  • Route Editor – GUI to create custom Garmin routing styles
  • mp2osm – GUI for converting Garmin mp files into OSM format (only works for non-copy-protected files).
  • img2typ – Takes a compiled Garmin map in .img file, extracts all POI/line/polygons types, and creates an editable TYP file that lets you customize that map.
  • … and more

LightSquared And The FCC – Still Doing Their Best To Destroy GPS

Back in February, I had a long post about the FCC’s conditional approval of LightSquared’s wireless broadband proposal. This waiver was vigorously opposed by the GPS industry because tests by Garmin showed that it would seriously disrupt GPS in areas where it was implemented. Read the post for a full rundown, but briefly LightSquared’s plan requires high-power transmissions in frequencies immediately adjacent to the GPS band, which drown out the GPS signal entirely. LightSquared dismissed these Garmin results, stating in a comment to my post:

… the Garmin tests that you refer to were not made under appropriate circumstances so the results are not accurate indications of how our network will perform. To get a real examination of the situation, tests must be conducted in the proper band and with the right filters. We’re now engaging in testing supported by the government and being done with the cooperation of many in the GPS community. We believe that this process will produce the most reliable results and will show that our network and GPS can coexist.

The FCC’s conditional waiver required LightSquared to form a study group with the GPS community to measure and analyze the potential effects of their broadband transmissions on GPS, and report back to the FCC by June 15th, 2011. Concurrently, the government’s National Executive Committee for Space-Based PNT (Position Navigation and Timing) asked a governmental interagency committee (National Space-Based PNT Systems Engineering Forum (NPEF)) to do its own separate, independent measurements to analyze LightSquared’s proposal, and also report their results in June of 2011.

Well, both reports are officially in, but enough results leaked out earlier to make their conclusions no surprise – the LightSquared system as originally described would completely disable the GPS system everywhere in the vicinity of a LightSquared transmitter, including applications for aviation, transportation, high-precision surveying, space, and consumer uses. This was the conclusion of both the LightSquared report, and the NPEF report. While the GPS industry and LightSquared were unable to agree on common wording for most of their conclusions, even LightSquared acknowledged that they were completely wrong in their original conclusion that “our network and GPS can coexist”.

End of story, right? Not quite. The original due date for the LightSquared report was June 15th, but they got a two-week extension from the FCC, apparently to give them time to come up with an alternative proposal that they claim fixes all relevant problems. It essentially consists of two major modifications to their original proposal:

1. Cut the maximum power transmission levels by 50%.

2. Not using 10 MHz of bandwidth closest to the GPS bands, and accelerating plans to use an additional 10 MHz further away, originally intended for service expansion in the future. LightSquared claims that 99.5% of GPS receivers would be free of interference from their transmissions.

The GPS community calls this a “Hail Mary” plan, and with good reason:

Cutting the maximum power transmission level by 50% is no cut at all (Source)

The FCC gave LightSquared approval to transmit at a maximum power of 15,850 watts, but LightSquared stated that its maximum operating power would be 1600 watts, 10% of the maximum. Cutting the “maximum power transmission level” drops that number to 8,000 watts, but unless the operating power is also cut by half, that will make no difference for GPS interference. LightSquared is unlikely to cut that power level in half, as that would require them to construct 4x as many transmitters as originally planned, increasing costs substantially.

“Giving up” 10 MHz of bandwidth may still incapacitate all GPS receivers, and definitely incapacitates all high-precision receivers.

As the GPS community’s rebuttal points out, LightSquared’s conclusion that their revised proposal will eliminate interference for 99.5% of current GPS units isn’t supported by the report they submitted to the FCC. Since LightSquared sprang their proposal at the last minute, without consulting with the GPS industry, most of the tests did not incorporate LightSquared’s new operating conditions. But those that did indicated substantial “harmful interference” to about two-thirds of GPS receivers in the general navigation category (meaning automotive receivers). In order for LightSquared to prove that their revised proposal wouldn’t have harmful effects to the vast majority of GPS devices, the tests would have to be repeated using the conditions of their revised proposal.

What’s more, the NPEF report indicates that several aspects of test conditions used in the LightSquared report tests may have resulted in underestimating the negative effects of LightSquared’s transmissions:

  • The broadcast power level for the LightSquared transmitters was actually lower than that planned for operational use. While the interference results were supposedly compensated for this based on simple distance/power calculations, the NPEF report stated that some interference effects could not be adequately compensated for using such a simple compensation.
  • Tests were done using just a single transmitter, but heavily-populated urban areas would require multiple transmitters, each of which could interfere with a GPS receiver. While modeling could be done to simulate these effects, accurate assessment of these effects would require testing with multiple transmitters.
  • Finally, the LightSquared receivers also broadcast in a frequency range adjacent to the GPS band, albeit a different frequency and lower power than their main towers. It’s possible that these receiver units might also interfere with the GPS signal, but since LightSquared still doesn’t have any of these receivers available for testing, it wasn’t possible to assess what harmful interference they might generate.

As an additional “bonus”, this 10 MHz “surrender” by LightSquared is only temporary – they plan to use that frequency space in the future for service expansion, which would once again, by their own admission, disable GPS receivers completely anywhere within the vicinity of a transmitter.

What’s more, LightSquared freely admits that the vast majority of high-precision GPS units, those used for “agriculture, aviation, construction, engineering, surveying, marine navigation and disaster monitoring as well as federal, state and local government uses”, would be rendered unusable even under their revised proposal. Their solution? Make the GPS industry, and users of those high-precision GPS units, pay to fix the problem themselves. Why and how? Simple:

Paint the GPS industry as mooching off the government

LightSquared commissioned a report from the Brattle Group concluding that GPS satellite transmissions from the government-run GPS program amounted to an implicit $18 billion dollar subsidy of the GPS industry, and that the GPS industry should therefore pick up the tab for any equipment modifications required to co-exist with LightSquared. Seriously? Don’t you know anything about the history and rationale behind GPS?

  • It was originally intended for military use, a function it still fulfills today. The incremental cost for consumer/industry use is trivial in comparison to the total costs.
  • After KAL Flight 007 was shot down by the Russians in 1983, President Reagan issued a policy directive that required the low-precision (Selective Availability) GPS signal to be made freely available for civilian use.
  • In 1996, President Clinton issued a policy directive that GPS officially be declared a dual-use (civilian and military system), and in 2000 that Selective Availability be turned off, making moderate to high-precision GPS signals available to everyone.
  • In 2004, President Bush issued an policy directive that no direct user fees be charged for GPS signals.

But now LightSquared, a commercial initiative that played no part in the development of GPS, feels it has the right to imply that the GPS community needs to shoulder the costs of their proposal? Please.

Accuse the GPS industry of being aware of this possibility, and not designing their equipment to be ready.

LightSquared claims that the GPS industry has known for years that terrestrial transmissions in adjacent frequency bands were coming, but did nothing to either fight them, or re-design their equipment to handle interference from these transmissions. Putting it mildly, this is a total crock. As Trimble’s response to these statements makes clear, these terrestrial transmissions were supposed to be “ancillary”, auxiliary low-power transmissions in limited areas where terrain or foliage blocked reception of the primary low-power satellite transmissions; the GPS industry acknowledged that it could live with such limited low-power terrestrial transmissions. The waiver granted by the FCC to LightSquared flipped this around completely, making the terrestrial component the primary one, and jacking up the transmissions power level by orders of magnitude. Unless the GPS industry had Nostradamus on the payroll, and he could have foretold that the FCC would completely reverse its position on broadcast power levels in these bands, it’s ridiculous to imply that the GPS industry knew this was coming.

Claim that fixing the issue is easy and cheap

LightSquared claims that cost of fixing a GPS receiver was trivially low, on the order of 5 cents for a basic filter, but that the GPS industry wasn’t willing to implement this fix. First off, LightSquared’s technical competence to make such statements is highly suspect, in light of their original position that their system would have no detrimental effect on GPS. Secondly, they are unable (or unwilling) to provide a demonstration GPS unit that incorporates these filters, merely relying on a chip manufacturer’s assertion that they could provide such filters; if it’s so easy and cheap, why can’t they prove it? The GPS industry, with far more experience, doesn’t think such a solution is trivial. The NPEF government report goes even further:

… add-on filtering solutions are not viable for a significant fraction of fielded equipment due to considerations such as performance (signal attenuation, increased thermal noise floor, phase and group delay variations with temperature and between frequencies, loss of narrow correlator benefits), cost, size, and weight.

For a new product, many additional degrees of freedom are opened for mitigation techniques… Unfortunately, redesign is not likely to result in the same level of performance provided by current receivers, especially those employing wide RF front-end passbands… High-precision equipment is among the most difficult to protect against the LightSquared emissions since these receivers typically process wideband GPS signals that require a wideband receiver passband and such equipment usually also has severe differential group delay requirements. For these types of receivers, filtering can typically significantly degrade or even destroy the very information required for the most demanding scientific and precision applications.

In its report, the NPEF concludes that the problems with the LightSquared proposal are so serious and intractable that they recommend:

  • The FCC immediately rescind the conditional waiver granted to LightSquared in January 2011, which would effectively put LightSquared’s planned system on hold
  • Six months of more rigorous tests of the possible effects of the LightSquared system on GPS, and make future decisions based on those results
  • The FCC determine whether any broadband system that relies on frequency bands adjacent to GPS could be implemented without interfering with GPS, and adjust their regulations accordingly if the answer is “no”.

In a sane and rational world, the FCC would adopt these recommendations immediately. But in a sane and rational world, they would never have granted LightSquared a waiver in the first place, even a conditional one. They’ve been tasked by the Obama Administration with freeing up frequency space for broadband, and they seem committed to that goal regardless of the facts. They’ve already shown their bias toward LightSquared (and against the GPS community) a number of ways:


A 30-day comment period now runs through the end of July, with a final decision due August 15th. Based on their past history, I would assume that the FCC will extend their conditional waiver, with possibly a requirement for a few more months of testing. And if the results of  testing shows that the main impact is on high-precision GPS receivers, my gut feeling is that they will grant final approval to LightSquared, and dump the responsibility and cost for “fixing” high-precision GPS receivers on the manufacturers and users. LightSquared apparently feels the same way, as they’ve announced that they’re going to start construction of their network right away, even before the final FCC decision is made.

But it’s my hope that other government bodies will step in to stop this process, and I have to believe they will. Since the waiver was granted in January, this issue has gotten more and more attention from affected industries, elected government officials, and the press. An amendment has already been attached by the House Appropriations Committee to a budget bill, prohibiting the FCC from spending any money or resources on the LightSquared proposal until they prove that it won’t interfere with the GPS system. If the FCC actually approves LightSquared’s plan, I think it’s likely that legislation will be passed quickly to override their decision. Apart from the FCC (and possibly the White House), there isn’t a single government agency that thinks this is a good idea. The Save Our GPS coalition has a growing list of GPS-dependent companies, from a wide variety of industries with substantial political influence, joined in opposition to the LightSquared proposal . In particular, I expect that any Senator or Representative from a farm state is a solid vote in opposition to LightSquared, given how important GPS is in modern industrial farmin. The powerful telecom lobby is aslo in full opposition, partially because of the potential for competition, and partially because LightSquared used loopholes and political influence to gain access to wireless bandwidth for far less than what the telecoms had to pay in open auction. LightSquared has very few friends in Washington, and a lot of opponents; ultimately, I’m optimistic that GPS will be saved.

Free Books From The National Academies Press

SlashGeo posts on the June 2nd announcement by National Academies Press that all their PDF book titles are now freely available for download, or for online reading. National Academies Press is the publishing arm of the National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council. A search using geography-related terms (e.g. GIS, GPS, geography, maps, cartography, etc.) will bring up long lists of titles. They’re a bit of a mixed bag, though – most of them are more along the lines of committee reports, executive summaries, available resources and project planning than they are of more practical applications. Still, worth a look, especially at the price ;-). For many of them, you can also buy hard copies, and even embed a widget for them onto your website to allow people direct access to the book.

Here’s a few potentially interesting titles I picked out with random searching (assuming WordPress doesn’t trash the embed code, the way it sometimes does):

Free Marine Chart Views, Plus An Online Waypoint/Route Editor With GPS Export

The Marine GeoGarage site offers free online views of marine charts from the following countries:

  • USA
  • Bahamas
  • Argentina
  • Brazil
  • Netherlands

A  10-euro monthly subscription (free 14-day trial) gets rid of the ads, and adds charts for the following countries:

  • UK and vicinity
  • Canada
  • Australia

Choose the country from the list at upper-right:


The slider controls the transparency of the marine chart overlay in Google Maps; slide it all the way to the right, and the map disappears completely (more on this shortly). Map detail level scales with the zoom, so if you start zoomed out:


And then zoom in :


Map detail scales accordingly, if maps are available at different scales.

There are three checkboxes in the control section:

  • photos – shows geotagged panoramio photos. There’s usually so many of them near coastal areas that this feature is pretty useless.
  • fullscreen – Blows up the map interface to full size (but doesn’t get rid of ads in the free version).
  • coverage – Shows the coverage areas for all marine charts available at different scales, useful for seeing whether you can zoom in for more information:



There’s a scalebar at lower left, with the option to set the distance units used, and view the cursor coordinates (though the latter is a bit slow to update):


So far, useful mainly for mariners. But the site also has editing tools that let you create GPS waypoints and routes; while these are useful for marine navigators, setting the map transparency to 100% lets you create terrestrial GPS waypoints and routes anywhere in the world. For example, by using the waypoints and routes toolbar:


Plus setting the marine charts invisible, and setting Google Maps to Terrain view, I can create/edit waypoints and routes:


And then export them to a GPX file for use on my GPS:


If you own a Garmin GPS unit, and you have the free Garmin Communicator plugin installed on your browser, you can even export the data directly from the website to a connected Garmin GPS.  Logging in with either free registration, OpenID, Google login, or other credentials, lets you save this data online for future editing and use.

A Review Of The Garmin 62s GPS, Part III – Waypoints And Tracks, Plus Conclusions

This is part 3 of my review of the Garmin 62s GPS; part 1 is here, and part 2 here. Today I’ll look at the Garmin 62s’s worst functionality – the way it handles waypoints and tracks. And I’ll sum up with my final thoughts and conclusions, both on the 62s, and on proprietary GPS units in general.


The ability to mark and save a location, or use a saved location for navigation, is an essential function for any handheld GPS unit. My older Garmin 60Cx does a great job at this, and using it as a model should have made the 62s comparable if not better. But Garmin made some bizarre choices with the 62s that make its waypoint functionality markedly inferior to the 60Cx.

Let’s start with the most basic function: marking a point. For both the 60Cx and 62s, you can do this just by pushing the “Mark” button from any screen. This is a huge improvement from the Oregon series, which often required you to exit your current screen and go to new one to mark your location. Here are the waypoint creation screens for both models:

Garmin 60Cx
Garmin 62s

Pretty much the same, except that the 60Cx has a button that lets you average the position measurement to improve accuracy, while the 62s doesn’t. Why not? There’s plenty of room, and there actually is a waypoint averaging function on the 62s. If you check the 62s manual, there’s no mention of this option anywhere on the page that describes creating a waypoint. But if you push the “Menu” button on the 62s ..


Bang – there’s the Averaging option, along with many other options, none of which are mentioned anywhere in the manual. How exactly is a normal user supposed to find this out? And why is the averaging option only accessible from this screen, instead of being a separate button? Basic functionality has been removed for no good reason that I can see.

You might notice that the waypoint icon in the 62s screen is an odd non-standard shape. The 62s, like the 60Cx before it, supports custom waypoint icons, up to 56 on the 62s versus 20 on the 60Cx; this is a really useful function for mapping. Want to use this function? Good luck …

  • It’s not discussed anywhere in the manual; I found out about it at the Oregon wiki site
  • Naming conventions for custom waypoint graphic files are different for the 62s than for the 60Cx
  • The 62s requires BMP files in 24-bit color, and won’t accept the 8-bit color BMP files required by the 60Cx. So if you have both models, you have to maintain different graphic files for each unit. Bizarrely, though, Custom Garmin POI files with 8-bit graphics will work fine on the 62s, so it will support 8-bit graphics; Garmin just decided not to, presumably to make everyone’s life more difficult.

There’s another way to create waypoints on a 60Cx – use the cursor pad to move a cursor to a different location on the map, and press the Enter button; you’ll get a screen with options to Save that location as a waypoint, show it on the Map, or automatically generate a navigation reference waypoint and “Go” to it. Try something similar on the 62s, and only the “Go” option shows up:

Garmin 60Cx
Garmin 62s

Huh? So I can’t create waypoints on the map by selecting a map location on the 62s? Well, actually you can, though it’s not documented in the manual; pressing the “Menu” button on the unit brings up that option:


Except that if you push this button, unlike the 60Cx, you won’t get the option to set the waypoint name and icon, or other parameters; instead, it will create a waypoint automatically with a number ID, and the waypoint icon set to the last used icon. If you want to change the name, you’ll have to go to the waypoint manager, select that waypoint, and change its parameters manually. And on the 60Cx, if you move the cursor, the geographic coordinates at the cursor point show up, along with bearing and distance; on the 62s, you get no coordinates, only bearing and distance, even though there’s more than enough room to display them.

So, on to waypoint management. On the 60Cx, you push the “Find” button, then select “Waypoints” to get a list of waypoints on the unit. You can do the same thing on the 62s as well:

Garmin 60Cx
Garmin 62s

Now select a waypoint from that list:

Garmin 60Cx
Garmin 62s

On the 60Cx, you get a standard waypoint info/edit screen; pressing “Map” will show the waypoint on the map. On the 62s, though, you get the mapped waypoint, and only the option to “Go” to that point. WTF? If you try pressing the “Menu” button, to get more options, you do get some:


But they’re pretty useless. “Review Point” brings up an info screen, and that’s all (location blacked out on purpose):


Turns out that if you want to edit an existing waypoint on the 62s,or delete that single waypoint, you have to go to an entirely different screen, the Waypoint Manager, which is accessed via the main menu. Why you can’t access it through the Find => Waypoints option, the same way you can with the 60Cx, I have no idea – makes no sense.

Garmin 60Cx
Garmin 62s

On the 60Cx waypoint list, if you press the Menu button, you can screen waypoints by distance, name, the current map reference unit, or the icon symbol, the last of which is really convenient. And under the “Delete” option, you can choose to delete all the symbols, or just the ones with a specific icon symbol, handy for deleting temporary waypoints you don’t need anymore. On the 62s, for some bizarre reason, Garmin decided to leave most of this functionality out. The default is nearest waypoints, with Spell Search required for searching by name. And the only option for deleting waypoints is to delete all of them; no filtering by waypoint icon. This is a huge pain.


So is the 62s’s Waypoint Manager any better than Find => Waypoints for handling waypoints? Nope. First screen looks identical:


Select a waypoint, and you’ll finally get the option to edit a waypoint:


But where’s the option to Delete it, which shows up clearly in the 60Cx waypoint info screen? Once again, you have to press the Menu button to bring up that option.


This is actually mentioned in the manual (!), but all the other options listed above aren’t. And you can’t delete all waypoints with a common icon; you either have to delete all of them, or delete them one at a time on the unit. Awesome.

One final idiocy. If you select “Go” to navigate to a waypoint, there’s no “Stop Navigation” option available from the menu on the map page, as there is on the 60Cx. You have to press the “Find” button to stop navigation. But if you do that, go back to the map page, and press the menu button, you will see a “Resume Navigation” option. Help me out, Garmin – why can’t you “Stop Navigation” from the map page, but you can “Resume Navigation” from the map page?



I was going to go through a similar look at the idiotic way that Garmin has implemented track management on the 62s, but after writing about the idiocies with waypoint management, I don’t really have the heart. But here are some bullet points:

  • There are actually some real improvements with track data storage on the 62s compared to the older 60Cx. The 60Cx had a maximum track point capacity for all tracks of 10,000 points, and a maximum of 20 stored tracks, each with no more than 500 points. The 62s allows up to 200 named stored tracks, each with up to 10,000 points. And it will actively archive the active track, so that you can have every point permanently recorded, up to the free memory available.
  • Unlike the 60Cx, tracks saved on the 62s include the date/timestamp for every point and the altitude.
  • However, turning track recording on and off is a pain on the 62s. On the 60Cx, there was a simple page that let you turn tracking on, save the active track to memory, then turn tracking off and clear the active track. This made recording linear or areal features easy. On the 62s, you can turn tracking on in the Track Manager, but you have to dive back into the Setup menu to turn it back off. And you can clear the current track out, but that’s at the bottom of the options list, and easy to miss.
  • Options for changing track color/name, reversing it, showing/hiding it on the map, displaying track length/area used to be centralized on a single screen on the 60Cx; now on the 62s you have to go to multiple screensfor the same options.
  • Sometimes a saved track simply refuses to show up on the regular map display, even if you’ve specified that it show up on the map.


Conclusions and Final Thoughts

I guess I’ll start with a Pros/Cons list for the Garmin 62s.


  • Solid hardware
  • Excellent screen visibility in all conditions
  • Improved interface
  • Improved map styling for better visibility
  • Support for raster imagery (super-awesome)
  • Terrific digital compass


  • Expensive
  • Appallingly bad documentation
  • WAAS performance slightly improved from Oregon 450t, but still pretty bad
  • Limitations on size of Custom Maps raster imagery
  • Incredibly lame waypoint and track management

If the Garmin 62s had come out three years ago as the first model with the new Garmin OS, I probably would have recommended it; the hardware is solid, and given my many positive experiences with past Garmin units, I would have anticipated that most of the negatives would quickly be fixed. But Garmin’s been releasing models with this new OS for over three years now, and the fact that these issues still exist gives one pause. If someone told me that I could only take one GPS unit out in the field with me, and I had to choose between my old trusty Garmin 60Cx and my newer 62s, the choice would be very easy. If I absolutely had to have aerial imagery in the field, the 62s would be my choice by default, since the 60Cx doesn’t really do aerial imagery well. But in every other situation, I’d take the 60Cx, hands down. If I’m recording position location, or navigating in the field, I don’t feel like wrestling with my GPS unit’s idiosyncrasies, and that’s what I’d be doing with the 62s.

Looks like there’s a lot of people that apparently feel the same way; at, the Garmin 60CSx (same as the 60Cx but with a compass and altimeter) is the top-selling handheld GPS with a color display, five years after it was first introduced. And there are two other older Garmin GPS units (the eTrex Venture HC and eTrex Vista HCx), and the Magellan Explorist GC, on the bestseller list before you get to the top-selling new Garmin model – the Garmin 62s. When five-year-old technology outsells a newer model from the same company, you know it has issues. I think an open OS like Android is the future for portable navigation systems of all kinds, and that proprietary GPS OSes are going to have a tough time competing. If a manufacturer is going to stick with its own proprietary OS on expensive GPS units, it’s going to have to supply a lot of added value with that unit. Frankly, I just don’t see that with the newer Garmin models, including this one. There’s finally been a ruggedized Android phone announced, the Casio Commando, and I expect more models will be along soon; if Garmin doesn’t get its act together quickly, it’s not going to be a major force in this market in a few years.

A Review Of The Garmin 62s GPS, Part II – Interface and Maps

Continuing on from Part I yesterday, today I’ll look at the interface on the Garmin 62s, and how it displays and handles maps.


I absolutely hated the touchscreen interface on the Oregon 450t I reviewed last year; doing even simple operations like creating a waypoint took multiple screen presses and changes. With the hardware buttons on the 62s, most of my objections no longer apply. A single button press can create a waypoint, and you can switch between different information screens (satellites, map, compass, trip info, waypoints, tracks) with just a few button pushes. Info screen order can be customized to show only a few screens, or all 24 available ones. You’re giving the option of flipping through full info screens sequentially, the default on my older Garmin 60Cx model, or using Garmin’s new Page Ribbon interface, which pops up a scrollable horizontal list of the info screens available, so you can jump immediately to the one you want:


And you can set up multiple profiles with different sets of info screens and  other configurations (tones, interface, units, etc.). This is a big step up from my old Garmin 60Cx, with only one profile configuration, and makes using the unit far more flexible.

The one downside to the 62s’s interface compared to the Oregon series is that inputting letters/numbers is easier with the Oregon’s touchscreen interface; with the 62s, you have to use the cursor pad to scroll across a keyboard to select individual characters. Even so, they’ve improved the keyboard dramatically from the old 60Cx and eTrex version, by expanding it and making separate keyboards for letters, numbers and symbols:


Garmin 60Cx keyboard
Garmin 62s keyboard

You can switch between different keyboards on the 62s with the buttons at lower left/right, or use the In/Out zoom buttons. While it’s not as easy as a touchscreen, it’s still not bad. Overall, the 62s interface is a substantial improvement from that on the 60Cx; two thumbs up.


Newer Garmin models, like the 62s and Oregon/Dakota/Colorado series, support both vector and raster map data.


There’s no denying that the Garmin vector map ecosystem is bigger and better than for either of its main competitors, DeLorme and Magellan. There’s a wide variety of map types available for purchase from Garmin, and any old mapsets you currently have will also work on this system. I have an old Garmin Roads and Recreation mapset from 1999 that still works fine on this new model; comparable Magellan mapsets from the same era either don’t work, or require complete reformatting. What’s more, they’ve modified the map styles on some maps to make them much easier to view. Compare these screenshots of the same topo map view from an old Garmin 60Cx and the new 62s; the maps on the 62s are much easier to view, especially in daylight conditions:

Garmin 60Cx
Garmin 62s

Having said that, the base 62s comes only with a very rudimentary basemap installed, and you’ll really need to get additional maps to get full use out of it. Compare that with DeLorme PN-60 model, which comes with a full US road and topo mapset (1:100K equivalent); or the newer Magellans, available with a full 1:24K-equivalent topographic map covering the entire US. Garmin really needs to start including better map data with their base units, if they want to stay competitive.

The 62s is also fully compatible with most custom vector mapsets created by hobbyists over the years using free or cheap tools; see my series on Garmin vector map tools for more info. These include all the 1:24K-equivalent US topo maps at the GPS File Depot site, which are completely free and of comparable quality to Garmin’s paid (and expensive) equivalents. Getting vector map data on a DeLorme requires their xMap software, which I believe is available for new purchasers of PN-series models like the PN-40 and PN-60 at a discounted price of $150. Magellan really doesn’t have any comparable legitimate capability; there are some people creating custom vector maps for Magellan units, but you have to use pirated software and a convoluted process to create them.

Also supported are custom map types, where you can redefine symbol sets for points, lines and areas to whatever you want. Excellent examples of what can be done with this capability are available in the New Jersey section of the GPS File Depot maps; Boyd has used this custom styling to create vector maps that look very similar to USGS raster topos. One exception to custom map type support are the vectorized raster maps generated by my Moagu utility; these take advantage of hardware quirks specific to the older 60Cx/60CSx models, as well as some eTrex models, and these quirks have been removed from the newer Garmin models. However, vectorized raster maps created by programs like MapWel or BMap2MP work quite well on the 62s (as well as Oregon/Dakota/Colorado models). My Moagu utility has a GUI front-end for BMap2MP with settings optimized for USGS topographic maps; these maps display almost as quickly as raster Custom Maps versions (more on this below), without Custom Maps’ restrictions on map size. Using this approach, you could get several dozen USGS topo maps at full resolution on a 62s or comparable newer Garmin unit, versus 6-8 using Custom Maps. Below is a screenshot from a 62s showing a USGS topo map creating using BMap2MP with the Moagu GUI and optimizations:




The newer Garmin models can support raster imagery, like scanned maps and aerial photography, directly. There are two ways to get this kind of imagery on a Garmin unit.

1. Garmin has a subscription service for world aerial imagery, called BirdsEye Imagery. For $30 a year, you get a subscription for unlimited downloads of aerial imagery (and nothing else); Garmin claims sub-meter resolution, but my local maps appear to be at about 1-meter resolution, and I’ve heard people in countries outside the US complain about poor data for their area. Download map data requires that you have Garmin’s BaseCamp software installed on your system, and a compatible Garmin unit connected to your computer. You can download sample data in BaseCamp, covering about one square kilometer, even without a subscription, so that you can check it out before buying it. Map data expires when the subscription expires. At least for my area, the aerial imagery is pretty good:


However, Garmin’s subscription service falls well short of what you can get from DeLorme’s comparable subscription service. DeLorme offers not only aerial imagery, but also USGS topographic maps and marine charts, for the same $30 subscription price. They also offer a separate subscription to Digital Globe satellite imagery, which offers 30-cm resolution across the world. You can also get Garmin BirdsEye topographic maps for some European countries, but it’s a la carte instead of subscription; $30 buys you up to 600 sq. km of topographic maps like OS maps for the United Kingdom; sounds like a lot, but it’s only an area of roughly 25 km x 25 km on a side, which really isn’t that big. On the other hand, Magellan has no comparable subscription service.

2. In October 2009, Garmin added a new feature to the Colorado/Oregon/Dakota/62/78 series called “Custom Maps”. You can take a scanned map or aerial photograph, calibrate it in Google Earth, then export it as a KMZ file for viewing on your GPS unit; here’s an example:


It’s a nice feature, and it’s great that Garmin added it for free, but there are issues:

a. The maximum image size you can create is about one megapixel; larger images will have their quality automatically degraded. You can get around this limitation using programs like G-Raster, mapc2mapc or OKMap, which can chop a larger image into smaller subtiles that meet this size restriction.

b.  A bigger problem is that there’s a maximum limit of 100 raster image tiles that can be viewed on a Garmin unit. Many people have asked Garmin to increase this limit, but so far Garmin hasn’t done so. They claim that it’s due to performance issues, but I have to believe that’s nonsense. It should be trivially easy to modify the unit’s software so that only maps in your current location were active, or to give people the option to disable/enable Custom Map files using the unit’s map manager, but Garmin hasn’t implemented either of those. I suspect they’re afraid that people will use Custom Maps instead of their BirdsEye subscription series, but given the extra steps required for Custom Maps, and convenience of BirdsEye imagery, I don’t really see this as a valid reason, especially on a unit as expensive as this one.

And BirdsEye imagery currently only includes aerial photography for the US, and not other commonly-desired raster imagery like topographic maps; if they’re not going to expand the range of imagery offered by that service, why not give users the ability to add as much of their own imagery as they want? As someone who was using my Moagu software to vectorize raster maps for Canada told me, Garmin’s BirdsEye service does them no good if it doesn’t offer the maps he needs, and Custom Maps doesn’t help if the total number of maps he wants on his unit exceeds their limits. There are people out there trying to reverse-engineer Garmin’s BirdsEye format so that you can create your own maps using that format, without the limitations of Custom Maps. But since this requires modifying your GPS unit’s firmware, and possible violations of the DMCA, I’m steering clear of that option.

By contrast, DeLorme’s xMap software lets you put any raster imagery you want on their PN GPS models (as well as GIS vector data like shapefiles). While it’s expensive at $150 (with a PN purchase), the combined cost of the most expensive PN model (PN-60) plus xMap software is comparable to the price of the 62s alone. So if the ability to put any maps you want onto your GPS is a requirement, you might want to give the DeLorme units a serious look. There are ways to put custom raster imagery on newer Magellan units, but they’re not exactly user-friendly yet.


Map management

You can install maps onto the 62s and similar models using Garmin’s old warhorse software, MapSource. However, Garmin seems to be slowly de-emphasizing that software in favor of their free BaseCamp program and its map installation utility MapInstall. I think MapSource is far easier to use for managing maps, but BaseCamp is better for managing tracks and waypoints, and is the only option for download BirdsEye imagery. However, MapInstall doesn’t let you save mapsets the same way MapSource did; every time you want to upload certain maps, you’ll have to select them manually.

The newer Garmin models do offer some major feature upgrades from older models in the way they handle maps:

1. Older models could only hold up to 2025 total map tiles; the new models can handle up to 4000 map tiles. This is, of course, not mentioned in the manual.

2. With older maps, there was a single map file generated that had to be called “gmapsupp.img”, otherwise the unit wouldn’t recognize it. And uploading a new set of maps erased the old set. If you upload maps to the newer Garmins, the same gmapsupp.img file is created. However, if you put the unit in mass storage mode and then rename the map file with a different name (but the same .img extension). the unit will still recognize it. This has some major advantages for map management. For example:

a. Upload all the topo maps for a state to your Garmin unit; the map file will be named gmapsupp.img.

b. Rename that gmapsupp.img file to something descriptive, e.g. az_24k.img.

You can now upload another mapset to the GPS without erasing the first one, something impossible on older Garmin units. You can also copy this map file from your GPS to your computer to archive it, and then delete it on your GPS unit to free up memory space. If you need these maps again,you don’t have to go through BaseCamp or MapSource to install it again– just copy the file back onto your GPS in mass storage mode,and the unit will automatically recognize it. This is an incredibly useful feature that is not mentioned in the manual.

3. Older Garmin units could only use microSD cards for storage up to 2 GB. Garmin says that the new limit is now 4 GB, but that’s a bit misleading. The maximum .img file size that can be created is 4 GB, but you can have multiple 4 GB .img files on a single card; people have reported using a 16 GB microSD card without problems. I’ve only used 2 GB, so I can’t confirm this. This is, of course, not mentioned in the manual.

4. Finally, thankfully, the new models use USB 2.0, up to 480 Mbps; older models used USB 1.1, painfully slow with large mapsets at 12 Mbps.

The map manager list is also somewhat improved from the older units; you now get full mapsets better defined, and easier to select:


From this list, select a mapset to enable or disable it; this includes not just vector maps, but also BirdsEye imagery and Custom Maps. There is one serious annoyance with this process, though. If you select a mapset by scrolling and pressing enter, that doesn’t enable/disable it directly; instead, you get a screen asking you if you want to Enable/Disable that mapset:


Attention, Garmin – a mapset is either enabled or disabled; there are no other options. So why not just enable/disable mapsets by selecting them and pressing enter; why do you require people to go through an extra screen with Enable/Disable options?


So far, for the topics I’ve covered in parts one and two (hardware, interface, maps, GPS reception), there have been pluses and minuses to the 62s, but on balance, I’ve had a pretty positive view of the 62s; the only major exceptions have been the expensive price, pathetic manual/documentation, and unreasonable restrictions on Custom Maps. But in Part 3, I’ll look at the way the 62s handles waypoints and tracks, which is a huge disappointment. Plus, I’ll wrap things up with my conclusions and recommendations.

Still Looking For A Good Fieldwork Handheld GPS: A Review Of The Garmin 62s Part I

A little over a year ago, I posted my wish list of features for a GPS that would be useful for navigating and recording information for field work. A few months later, I reviewed the Garmin Oregon 450t, and while there were things I liked about it, overall I found it less than ideal for that purpose. About half-a-year ago, I posted on why I thought that Android represented  the future of handheld GPS units, over those with custom proprietary interfaces. Since then, I’ve been hoping that a rugged Android-based GPS would come out.

But late last year, I needed a rugged handheld GPS receiver capable of displaying aerial imagery and raster topographic maps. While my Android phone has that basic functionality I needed, it wasn’t rugged enough to handle the abuse it was likely to see,and no rugged Android GPS units had yet come out. I’d seen a number of reviews of the new Garmin 62 series of handheld GPS units, which supposedly address some of the shortcomings of models in the Colorado, Oregon, and Dakota series. I’ve been a Garmin fanboy for over 10 years now, love my Garmin 60Cx (same as the bestselling Garmin 60CSx minus the compass and altimeter), and am deeply immersed in the Garmin ecosystem. So, I decided to stick with Garmin and pick up a Garmin 62s, instead of switching to a model from deLorme or Magellan. Having had it for three months now,I’m now ready to pass judgment on it, both in comparison with my tried and trusted 60Cx, and with the potential I see in Android models.

Available Models

The Garmin 62 series currently comes in three different models. The fundamental GPS capabilities are the same on all three, but there are some distinctions:

Garmin 62 – $305 at – The base model; has 1.7 GB of built-in memory, which can’t be expanded. I dismissed this model because of the lack of memory expandability, but turns out that 1.7 GB is more than adequate for most applications, and I could have easily lived with it.

Garmin 62s – $390 at – Adds a digital magnetic compass, barometer, wireless ANT radio, also 1.7 GB of memory, and you can expand the memory capacity with microSD cards up to an additional 16 GB. This is the model I got.

Garmin 62st – $470 at – Like the 62s, but has the Garmin Topo 2008 mapset for the entire US installed (equivalent to 1:100K USGS topos); this leaves you with only 400 MB of free base memory, but you can expand that using microSD cards. I don’t recommend this model under any circumstances; you can get better topo maps for free from the GPS File Depot site, and upload only those that you plan to use. Even if you want the Garmin Topo 2008 maps, you can get them in DVD format for about $70, which makes the combined total for the 62s and topo mapset less than the 62st.

I have to say, the prices of high-end handheld GPS units are getting to be very unreasonable. For $400, you could buy two netbooks, one semi-decent laptop, or an Android tablet; what is is about these units that makes them that expensive, comparatively? In other areas of consumer electronics, prices have plunged dramatically over the years, while the feature set has expanded greatly; not so with Garmin’s GPS models.

Note: The Garmin 78 series has the same basic electronics as the 62 series, but is designed for marine use, so they float and have map options more appropriate for marine navigation.


Basic unit

After 2.5 years of Garmin releasing model after model with touchscreen interfaces and patch antennas, with limited commercial and technical success, the 62s is a return to the classic front-panel pushbutton and helical antenna design made famous by the 60 series. In fact, from a distance you’d have a tough time telling them apart:


Left: Garmin 60Cx; Right: Garmin 62s

But if you hold them in your hand, you can quickly see and feel the differences, most of which are in the 62s’s favor:

  • The 62s is thicker in the upper part, but tapers down to thinner at the bottom, which makes it easier to hold.
  • The buttons and cursor pad have been enlarged and angled on the 62s, which makes them easier to identify by touch, and easier to use, especially the cursor pad.
  • Most of the 62s is covered by a rubberized coating, which makes your grip more secure, especially when wet. Both models are IPX7 water-resistant. One downside of this is that it moves the lanyard attachment loop to the bottom of the unit, less convenient than the side loop on the 60Cx.
  • 62s is about a half-ounce heavier than the 60Cx (8 oz with batteries vs. 7.5 oz), but that’s barely noticeable.

Overall, I’d call the 62s a big step up ergonomically from the 60Cx (which was pretty good to begin with). And I’m glad that Garmin finally realized that touchscreens aren’t always the best solution for everyone. Early units apparently had a “creaking” problem, where they would make noises when you pushed the on/off button; my model was apparently a later production run, as I didn’t hear that problem.

Screen display

One of the biggest problems I had with the Oregon 450t was screen visibility in sunlight; while not horrible, making out map details could be a chore, even with the high 240 x 400 pixel resolution screen. The 60Cx’s 160 x 240 256-color transflective screen had lower resolution and color depth, but you could actually use it outdoors, which is a good thing. I’m happy to say that the 62s’s 65K-color transflective 160 x 240  display is a huge improvement over the Oregon 450t. I’d go so far as to call it equal, maybe even slightly superior, to the screen on the 60Cx. As an added bonus, the LED backlight is much brighter on the 62s than the 60Cx (or Oregon 450t), which helps with visibility in shaded or dark conditions. Full props to Garmin.

Having said that, though, Garmin’s use of the screen space and capability leaves something to be desired. For example, some Garmin mapsets support shaded terrain display on maps, and this is set as the default view. Looks great in a screenshot, but in daylight use it renders some maps virtually unreadable. Fortunately, you can turn this off, and I recommend that as one of your first things you do with a new unit. A bigger problem is that the 62s is running an OS originally designed for use on units with higher screen resolution, and usually a larger screen size as well. When it runs on the 62s, with a smaller screen and lower resolution, there can be issues. Text rendering, especially for small fonts, can show aliasing issues. And there’s a whole lot of extraneous detail on many screens that uses up valuable screen real estate. Compare these two satellite screens from the 60Cx and the 62s:

Garmin 60Cx
Garmin 62s

The first time I made this comparison, I had to pull out my ruler to check the screen sizes of the two; it almost seemed as though the 62s had a smaller screen. Turns out that they both have the same screen size, it’s just all that extra “box framing” on the 62s, which uses up so much screen space that they had to reduce the actual data display size; this problem crops up over and over again on the 62s. On the Oregon series, with a larger screen and higher pixel pitch, this isn’t an issue, but for models with smaller screens and lower resolutions, I think Garmin needs to customize the screen displays a bit better. I also have to say that I find the fonts on the 60Cx superior as well; they look better, and are more easily readable.

Battery life

Not quite as good on the 62s as the 60Cx, but still solid; I got 15-20 hours on hybrid NiMH rechargeables, about 3 hours less than on the 60Cx. The improved screen visibility helps with this, as you don’t need to use the backlight as often. The 62s comes with a “Battery Save” mode that supposedly turns the screen off after a few minutes while leaving the GPS receiver on; touching any key brings the screen back. I tried using this feature, but couldn’t get it to work for me.

GPS Reception

Overall, pretty good on the Garmin 62s, but my subjective opinion is that the 60Cx picks up more satellites more quickly, and in tougher conditions (e.g. indoors). WAAS performance on the 62s is a big step up from the Oregon 450t, but still isn’t perfect; both the 62s and Oregon use the same Cartesio chipset, and Garmin has been struggling for almost three years now to fix WAAS reception problems with that chipset. There are three WAAS satellites high in the sky where I live, and sometimes the 62s will cycle through signals from all three without locking in; other times, it will lock in immediately on a signal, and not drop it the way the Oregon 450t would. My 60Cx never has a problem getting a WAAS signal, even indoors; I find it difficult to understand why a newer model is so inferior in performance. Once a WAAS signal was acquired, the positions of both the 60Cx and 62s were identical to within a meter or two.

4/9/2011: After a week in the field, I’m far more disappointed and disgusted with WAAS on the 62s. I was out in an open area, no topography to speak of, and all three WAAS satellites fully visible, and more often than not the 62s couldn’t pick up a single WAAS satellite. That’s just pathetic.

Some people have noted issues with distance tracking at low speeds using the 62s’s built-in odometer; I tried to check that, but discovered that the odometer settings was frozen and couldn’t be reset. I am using the latest beta version of the firmware, so that might be responsible for this issue. Given that I’ve owned it for 3 months and only discovered this today, it tells you how often I use that feature; but if it’s important to you., you probably should check it immediately after buying the unit, and/or avoid beta firmware.


One thing I really did like on the Oregon 450t was the three-axis compass, and the 62s doesn’t disappoint on this score; these digital compasses on the newer Garmin models are the best I’ve ever used. I wasn’t terribly impressed with the performance or utility of the compass on the Garmin 60CSx, but the 62s compass has changed my mind. A digital compass lets you rotate the map to match the direction you’re pointing, or rotates the map location cursor to point in your direction when you’re standing still. Garmin’s new Sight N Go feature is also a terrific use of the compass; if you need to move in the same compass direction over a long distance, just point your GPS in the desired direction, push a button, and the Garmin will guide you to maintain that direction.


The 62s and 62st come with built-in ANT low-power wireless capability; you can use it to send waypoints to another compatible unit, interface with heartbeat/cadence sensors, and receive signals from Garmin Chirp beacons. I didn’t experiment with this since I didn’t have any compatible equipment, but naturally I still have an opinion. I think having wireless is a good idea, but I have to wonder why Garmin chose the ANT standard instead of the more common Bluetooth standard. Bluetooth would have opened up the ability to wirelessly communicate position with computers and phones, which would have been incredibly useful.



The 62s only comes with a quick start manual, no full guide. I understand this; paper manuals are expensive, and can’t be kept up to date the same way electronic documentation can. So I went to the Garmin website and downloaded the PDF of the latest manual. To call it bad is to praise it; it’s horrible, execrable, totally inadequate. These GPS handheld units do not have intuitive interfaces and obvious functionality; they absolutely need a full, complete manual that clearly documents all their features. The Garmin manual is hopelessly insufficient for that task; it barely covers the basic functionality adequately, much less the full feature set. This is a very expensive consumer hardware product, and for it to have only this lame excuse for a manual as the only official documentation is a disgrace. Garmin should first be ashamed of themselves, and then fix this problem.

I’ll bring up several examples of critical/important features that aren’t in the manual further on, but let me just highlight one an egregious example that affected me. If you go to the section in the manual that talks about the USB computer interface, you get this:


Looks like this unit supports the serial NMEA interface for position data that many programs require, right? Except …

  • You need a special USB to DB9 cable, or a custom cable to hardwire a connection; that’s an extra $20. Not mentioned in the manual
  • You also need a serial port to hook the cable up to; most computers these days don’t have one, so you’ll need to buy a USB-to-serial adapter for an extra $30. Not mentioned.
  • If you set the Garmin to any of the interfaces listed above, and connect a USB cable, the unit will automatically go into Mass Storage mode; there’s no obvious way to keep the unit in standard GPS mode while externally powering it from a USB cable.
  • The manual doesn’t list or describe any option to transmit GPS position data from the unit to a computer, for use with compatible programs like Google Earth that take the Garmin USB connection format.
  • But if you go to the actual unit screen described by the manual, you discover an additional interface option not mentioned in the manual called Garmin Spanner…


Using this option lets you power the unit off a USB cable connection, and also transmits position information to a computer via the standard Garmin USB protocol. This isn’t mentioned anywhere in the manual!

  • Furthermore, Garmin has a program called Spanner, which converts the standard Garmin USB protocol to the serial NMEA protocol that many programs require; it even lets you split the signal into multiple virtual NMEA connections so that you can use it with multiple programs at the same time. I assume this is why Garmin labeled this connection as “Spanner”. The problem is, the Spanner software only works with Windows XP; Garmin has specifically stated that it will not update it to work with Vista or Windows 7. This is retarded!

Magellan did it right with the Triton series; if you set those units to NMEA and connected them to a computer with the USB cable, a virtual serial port was created through which the unit could send data to programs that require NMEA. Why Garmin couldn’t figure out how to do that, I have no idea.

While some might consider this an obscure technical detail,  there are dozens of important 62s features that get no mention at all in the manual (I’ll highlight a few later on). The only place I know of to learn of many of them is the Oregon Wiki site; while not all Oregon features have a counterpart in the 62s, many do, and this wiki does a good job at explaining many of them.

Tomorrow: The OS interface and maps on the 62s -  the good and the not-so-good.

Cheap GeoPDF To GeoTiff Converter For Garmin Custom Map Imagery

The USGS is well on its way to having updated all its 1:24,000 scale topographic maps (the classic 7.5-minute series) to digital format. As of today, the coverage map looks like this:


Areas covered in red are full topographic maps in in digital format; areas in yellow are “Digital Maps”, which have transportation features, boundaries, geographic names and aerial imagery, but no topographic contours or hydrographic features. According to the current schedule, most of the US will have either full topos or “Digital Maps” by the end of 2011, with Digital Maps scheduled for upgrade to full topographic maps starting in 2012:


On one hand, the maps are very nice – they have multiple data layers, each with a separate kind of data, whose view can be turned on and off. Most data layers are vector, which means no more scaling/pixelization issues. On the other hand, the maps are currently only available in GeoPDF format, which limits their usability, particularly in GIS-related software. This was a conscious decision by the USGS:

The US Topo was not intended to be a GIS product. It was designed to serve users who need medium-scale topographic and orthoimage maps, but who are not GIS users.

US Topos are derived from GIS data. Almost all these data are from USGS and other government sources, and most are available for free through web services or file download sites. The US Topo represents a repackaging of these data, not new data creation. The primary design objective was to provide these data in a convenient and familiar form to people who need maps but who are not professional cartographers. The traditional 7.5-minute quadrangle layout and PDF format were selected as the best way to accomplish this objective; the GeoPDF extensions were adopted because they added some cartographic value at no cost to the end user.

Which is fine, but it still leaves some serious drawbacks with the format:

- As mentioned, not supported by most GIS programs, and I know that USGS topos are often used as the background base layer for maps. The USGS FAQ page mentions ArcGIS ($1500) and GlobalMapper ($350) as two options for converting GeoPDFs to GeoTiffs, but the price puts those out of reach of many.

- Printing the maps is a pain if you don’t have a large-format print, especially if you’re only interested in printing a subsection. The USGS Quickstart guide describes how to do it with Adobe Reader, and it’s not exactly a one-step process; what’s more, it’s virtually impossible to print to scale using their recommended procedure.

- Feature contrast isn’t always optimal, especially if you have the aerial imagery background turned on, and there’s no way to adjust that on a GeoPDF (unlike a GeoTiff).

- Newer Garmin GPS units support the Custom Map format, which lets you view custom raster imagery on the display screen; however, GeoPDFs aren’t in a raster imagery format that can be converted to this Custom Map format.

I’ve written a Garmin Custom Map utility called G-Raster, which converts GeoTiffs and other raster imagery types (KMZ overlays, MRSID, ECW, OziExplorer, graphics with worldfiles, BSB) into a Garmin-compatible Gustom Map format. Most features are free, but a few are unlocked with a $5 registration fee. The latest version (4.0) adds a new feature: a GeoPDF Tool GUI which can convert many (albeit not all) GeoPDFs into GeoTiff format. Interface is pretty bareboned – just specify the desired DPI of the final image, choose the GeoPDF filename, and a GeoTiff with the same name (but with “_gt” appended to the filename) will be created in the same directory as the original file:


Also generated with the “listgeo” utility will be a “.gtf” file with that GeoTiff’s metadata; this file can be used to re-embed the metadata into a GeoTiff file that has been enhanced by a graphics editor that does not preserve geographic metadata.

For example

1.  I converted the Fruita, UT next-generation PDF into a GeoTiff:


2. Garmin GPS units can have contrast issues when used in sunlight. So I loaded the GeoTiff into Photoshop to enhance contrast, and saved it under a different name; this process improved visibility, but also stripped out the geo metadata:


3. I embedded the “.gtf” metadata back into the enhanced Tiff file using another tool included with G-Raster, and then converted it into a Garmin Custom Map (screenshot from my Garmin 62s):



Other features and limitations of the tool:

- The unregistered version limits you to a maximum size of 2000 x 2000 pixels; images larger than these limits will be cropped. Registering the program removes these limitations. This way, you can test the tool to make sure it works for you.

- Works fine with all next-generation USGS topo maps and Digital Maps in GeoPDF, as well as older maps in the UTM coordinate format. Some older GeoPDF topo maps that are in the Lambert Conformal Conic projection don’t reproject correctly; the GeoPDF Tool will identify those problematic files, to let you know they may not be correct.

- The USGS 1:24K input option in G-Raster will crop the collar of these next-gen topographic maps; another new option in G-Raster will let you export this collared topographic map in GeoTiff format (geographic projection, WGS84).

- Not all datums are currently supported; unrecognized datums are assumed to be WGS84. This is a good assumption for newer maps, a poor assumption for older ones. I do know that it does support NAD27 and NAD83 datums.

- There’s currently no way to turn off data layers in the GeoPDF when exporting it to GeoTiff format; all data layers are included. The help file includes a mildly-convoluted work-around hack that will let you create GeoPDFs with data layers turned off.

- Once in GeoTiff format, the next-gen topo maps can be opened in any compatible GIS program or graphics editor; you can then enhance/crop them, and easily print a smaller subsection. You can also print them to scale, or use poster printing to create maps larger than your printer’s maximum paper size.

More information about G-Raster, and a link where you can download it, can be found at the G-Raster web page.