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Archive for the 'GPS' Category Page 6 of 25



A Review Of The Garmin Oregon 450t GPS For Field Work: Part II – The Touch Screen Interface

See this post for Part I of this review.

Starting with their Colorado GPS unit, which had a click-wheel-like “Rock N Roller” controller, and moving on to their Oregon and Dakota units, which rely exclusively on a touch screen interface, Garmin has moved away from having multiple physical buttons on their units to access functions and different screens. There’s nothing inherently wrong with that; replacing physical buttons with a touch screen lets you make a smaller unit, with less parts that can break. And it can give you greater flexibility in designing an optimal user interface.  But separate buttons also allow you immediate access to unit functions regardless of what’s currently being displayed on the screen; you have to be careful and clever in designing a touch screen interface that works in a similar manner. Unfortunately, the touch interface for Garmin’s Oregon GPS units (and the Dakota series as well) fails in that respect; operations that were simple and easy on older units are now a chore on the newer ones.

Let’s take one of the basic procedures you’re likely to do on a regular basis with your GPS: record your current position as a waypoint. I’ve been using handheld GPS units for 17 years now, starting with the Motorola Traxar, the first “consumer-grade” GPS unit. With every one of those units up until the Oregon, if I wanted to bring up a screen to record and edit all of the parameters of my current position, regardless of where I was in the menu/interface, I could push a single button and bring up the waypoint recording screen. Fast, simple, easy.

Not so on the Oregon/Dakota. If you’re in the map display, which is where you’re likely to be most of the time, you’ll see something like this:

map

There’s no single button to push to record your position (the “x” in the lower left takes you back to the main menu screen); instead, you have to:

1. Exit from the map screen.

2. On the menu screen, press the “Mark Waypoint” button.

3. Choose either the “Save” option (to save it with the default name and icon), or press the “Save and Edit” button to bring up another screen to let me modify various parameters.

4. If I choose to edit, I have to scroll down a screen of various parameter buttons (Name, Photo, Symbol, Comment, Depth, Elevation, etc.), press a button to change that single parameter, exit that screen, press another parameter to change that one, and so on.

You have more parameters to choose from, I suppose, and the touch screen makes entering data a bit easier. But why isn’t there a simple way to reach a single screen that lets you see and modify all the parameters at once, instead of this “one-at-a-time” piecemeal approach? What should be the simplest operation you do on a regular basis becomes a chore. Why isn’t there the option for one or two user-selectable buttons that can access common functions with a single press from any screen? Or, for that matter, a few more physical buttons on the outside of the unit that the user can assign functions to?

The more time I spent with the Oregon, the more frustrated I became with the interface choices Garmin made; everything seems to be organized to take far more time than necessary. Take, for example, the main menu where you access functions. There are about 20-odd functions that can be included in this main menu, but Garmin made the function buttons so large that only six can appear on the screen at one time, two columns by three rows:

menu

To access additional functions, you have to use the scroll buttons at the bottom; if you leave all the function buttons enabled, that’s four screens to scroll back and forth across. Shrink the buttons just a bit, and they could fit 3 x 4 = 12 buttons on a single screen, and all the buttons on two screens.

A few more annoyances:

– Garmin is in love with scrolling/expanding/shrinking display changes, when a function screen appears or disappears. It’s clever the first few times, but rapidly becomes a pain, especially as you have to dive through five or six of these screen changes to reach a desired function. It wastes time, and processor power; just let the screen pop up instantly, OK?

– With the old GPSMap and eTrex interface, track management and control was consolidated in a single screen. I could turn tracking on, record a track, turn the tracking off, and then save the track under its own name with minimal effort. Not any more. While there is a Track Manager function, you can only turn tracking on here. If you want to turn it off, you have to exit the Track Manager, go to the Setup Screen, choose Tracks, go to the Track Log button, and turn off track recording. Same thing for changing the track recording method and intervals. Why is all this functionality not available from a single screen, as it used to be?

– On older units, if you were looking at the map display and wanted to change the map data you were looking at, or map parameters, those screens were a few quick button pushes away. Not any more; once again, you have to exit the Map Screen, go to Setup, go to Select Map, scroll (slowly) through the list of available maps, click the button for the map you want to display, then press the Enable button. The ability to change the map data being displayed is one of the most commonly-used functions on such a GPS unit; why is there no option to make this accessible via a single button push?

– While I’m on the topic of maps; take a look at the list of available maps that I loaded on my review unit:

maplist

It’s bad enough that the buttons are huge, requiring you to often scroll down through even a small number of maps to reach the mapset you want. But you see that button at the bottom for the Arizona Geological Formations mapset? You’d think I’d be able to tap that to select it, but noooooo – it’s not completely on the screen. So I have to scroll down again until the button is completely on the screen before I can select it.

– There are occasions when you need to scroll through a long list. If you’re at the top of the list, you’d think it would make sense that if you hit the scroll button to go up, it would wrap around and show the bottom of the list right away; same thing if you’re at the bottom and want to jump to the top. Nope; have to scroll all the way through the list to reach top or bottom, regardless of where you are.

– The position indicator (the blue triangle on the map image above) is far larger than it has to be; it’s about 3-4 times larger than the comparable indicator on the 60Cx. Not a big deal with vector maps, but now that you can put raster imagery on an Oregon, it can block out too much of the image, especially if you have an aerial/satellite photo displayed.

… and I could go on and on. Organization of basic functions is scattered all over the place; accessing them takes way too much time and effort; the interface is poorly designed and laid out; more thought seems to have been given to making the interface look “cool” than actually making it functional and easy to use. I’ve been a huge Garmin fanboy for about a dozen years, starting with the 12XL, then the eMap, and then finally my most recent Garmin, the GPSMap 60Cx. The Oregon 450t isn’t a bad GPS unit, and I’ll be a bit sorry to send it back, but it’s a huge disappointment. Without a serious re-working of the whole interface, I’d have a tough time recommending the Oregon/Dakota series to anyone. Given the choice between the 2010-vintage 450t model and the 4-year-old 60Cx model, there is no choice – the 60Cx, for all its limitations, is a better GPS unit for field work.




A Review Of The Garmin Oregon 450t GPS For Field Work: Part I

A few weeks ago, I did a post called “In Search Of The Perfect Fieldwork GPS”, a list of the features I’d like to see in a handheld GPS unit designed for serious fieldwork and mapping. The Magellan Triton 2000 GPS unit, which I reviewed last year, had some but not all of these features, and while it’s a decent GPS it’s just not good enough for fieldwork. Recently, Garmin was nice enough to send me one of the latest models in their Oregon line of GPS units, the Oregon 450t, for review:

This post will look at the basic hardware and GPS performance of this unit, comparing it with the Magellan Triton 2000 and my old-school Garmin 60Cx. Tomorrow’s post will be a review (rant?) of the Oregon’s touchscreen interface.

The Oregon 450 series, another touchscreen model, is a follow-on to the Oregon 550 models introduced in mid-2009, and the successor to the Oregon 400 series. The biggest difference between the 400 and 450 series is the tri-axial compass on the 450, which works at any angle; the compass on the 400 requires you to hold the unit horizontally. Comparing the 450 to the higher-end 550 units, the 450 models don’t have the built-in 3 MP digital camera found in the 550s. I think a camera is a useful add-on for a fieldwork GPS; while the 3 megapixel sensor is a bit small, I’ve heard that you can focus from two inches to infinity with this camera, making it useful for both closeup and distance shots. A “t” at the end of a model number indicates that it has a 1:100K-equivalent US topographic map dataset pre-loaded into the unit; non-“t” models have a simple basemap installed, plus an elevation database that lets them display shaded terrain relief and 3-D views.

At 2.25” x 4.25”, the Oregon is substantially smaller than either the Triton or 60Cx, and fits comfortably in my hand. I think I would have liked to have seen a bit more texturing on the outer surface to help with the grip, since the unit only has the power button to break the surface continuity. Still, the “rubbery” edge of the unit shouldn’t make hanging on to it too difficult, even in wet conditions. There’s a lanyard hole at the bottom of the unit, but no lanyard is included; instead, a carabineer clip can be slid onto the back, letting you clip it onto your belt or pack. I’d personally prefer a lanyard, and buy a separate belt case/clip. While the unit is small, it weighs just slightly less than the Triton or 60Cx, so it actually feels heavier than those units even though it’s not (weight vs. density).

Documentation: Only a quick-start guide was included in the package. You can download a PDF user manual from the Garmin website, but even it is seriously lacking in basic information about the unit. I can’t recommend the Garmin Oregon GPS Wiki enough as a far more complete documentation source for the Oregon line than anything Garmin puts out.

Software: None included.  Unlike the 60Cx model, the Oregon does not come with Garmin’s MapSource program, which allows you to manage and upload vector mapsets to your Garmin unit; you have to either pay for a Garmin mapset that includes this program, or beg/borrow/steal a copy from someone else. A recent update to Garmin’s Basecamp software added the ability to upload mapset data, but I find this program far inferior to MapSource for this purpose. This is nickel-and-dime stuff; for the price you’re paying for this unit, a copy of MapSource should be included.

Computer interface: Mini USB plug, and thank God it’s USB 2.0; older Garmins had USB 1.0, which made large map transfers painfully slow. One annoying feature is that the only way to use USB for power only is to have the USB interface set to Garmin Spanner; in other interface modes, the GPS unit display is turned off automatically. On the flip side, you have the option of an NMEA serial interface through the USB connection, which is useful for those programs that only work with NMEA connections.

Battery life: I got a respectable 15-20 hours out in the field from the recommended NiMH rechargeable batteries, far better than the Triton, slightly worse than the 60Cx.

Display: The 3” diagonal, 65K-color 240 x 400 display is gorgeous when viewed under the right lighting conditions and angle. When the first Oregon units were released, many people complained about display visibility, especially in sunlight conditions. I don’t have an older model for comparison, but I can say that this Oregon’s display is very usable in sunlight conditions, far better than the Triton. Outdoors under reduced light (cloud or shade), the display is less than ideal unless you turn the backlight on at full intensity; even then, it’s not great. Terrain shading on maps looks great in screenshots, but in the field, you’ll get better results by turning it off. Oddly enough, the Triton display is better under those conditions when the backlight is turned on. The Garmin 60Cx is far better than either of those in all lighting conditions, at the cost of reduced color depth and resolution; still, a low-color display you can see is better than a high-color one you can’t.

One final problem with the display: since it’s a touchscreen, it’s going to get covered with fingerprints pretty quickly, and these can degrade screen visibility, especially in sunlit conditions.

GPS Satellite Reception: The Oregon units have small ceramic path antennas, which require you to hold the unit horizontally for optimal reception. I wish Garmin had stuck with the larger, omni-directional quad helix stub antennas found on their 60Cx and Colorado units; while they might break up the “clean” look of the unit, you’d get better reception at all angles. And there’s no connector on the Oregon for an external GPS antenna that might improve reception. I consistently acquired more GPS satellites on my old Garmin 60Cx than on the newer Oregon model. Still, outdoor reception with the Oregon for the regular GPS constellation is acceptable under most usage conditions, even holding the unit at an angle, and is superior to the Magellan Triton. I also liked the unit’s ability to store GPS satellite data to increase acquisition speed the next time you turned it on. WAAS reception was very problematical; even under wide open skies, with no terrain blockage and two WAAS satellites high in the sky, picking up a WAAS signal could take as long as half an hour, and the WAAS signal frequently dropped out. Even when a WAAS signal was received, not every GPS satellite signal had the “D” indicator showing that the GPS position was being properly corrected. Not a huge problem now while the sun is currently in a quiet phase, but that will change as the sun moves towards a more active phase over the next few years; Garmin needs to fix this issue ASAP. Neither the Garmin 60Cx or Magellan Triton had similar WAAS signal problems.

Positional accuracy: For a quick qualitative analysis of positional accuracy, I loaded high-resolution calibrated aerial imagery onto both the Garmin Oregon and Magellan Triton, and tested them under fully open skies (no terrain or tree blockage). Both were equally excellent in positional accuracy; while the displayed error estimates were on the order of 5 meters for both units, the actual error based on the aerial imagery was on the order of 1-2 meters.

One thing the Oregon has that is sorely lacking on the Triton is waypoint averaging; for good waypoint accuracy for serious field work, this is essential. Garmin suggests returning to a specific point several times to do waypoint averaging that takes into account errors due to satellite geometry; I’d suggest to Garmin that they include Dilution of Precision (DOP) in the display, letting people know how good the current satellite geometry is.

average

Compass: I’ve used GPS units with built-in compasses before, and always wound up turning them off. Accuracy was always questionable; direction readings tended to be “jerky”, jumping around continuously; the need to hold the unit horizontally limited the utility. The compass on the Oregon 450t has none of these problems; it’s the best GPS compass I’ve ever used, by far. Accuracy is outstanding when you follow the simple calibration procedure; readings are smooth and solid; the “tri-axis” functionality lets you hold the unit at any angle and get an accurate reading. It’s not a complete substitute for a good handheld compass, but it’s not that far off, either. A+ for Garmin on this one. If they could only add a feature that would let you measure the angle from level at which you hold your unit, it would be fantastic for combined angle/direction measurements like slope and dip/strike.

Compass screen:

compass

Maps: Every standard vector map I tried on the Oregon unit worked perfectly, including custom maps with standard feature types. I tested some custom maps with custom feature types, and they worked as well, but there’s no guarantee with those that all of them will work. As I mentioned above, terrain shading looks great with some of these maps when you do screenshots, but doesn’t work that well in real-life, and I turned it off right away. In terms of map variety and availability, Garmin blows Magellan away completely; in addition to Garmin’s own proprietary maps, a search on this website and others like GPSTracklog will bring up many sources of free Garmin maps (e.g. the GPSFileDepot).

Last year, Garmin added the capability to display raster maps on the Colorado/Oregon/Dakota series, and included the capability for you to create your own maps for free. I give Garmin major props for that, as no other GPS maker has done that. deLorme requires you to pay $200 for a copy of xMap in order to put your own raster data on their GPS units. Magellan has never released any official way to put your own raster maps on their Triton units, limiting your official choices to maps sold by them (though there are now free unofficial options for generating Magellan Triton raster maps, like TritonRMP Maker, RMP Creator and Mobile Atlas Creator).

Having said that, though, there are currently too many limitations on raster map functionality on the Oregon for it to be fully useful right now. No map segment can be larger than one megapixel in size (1024 x 1024 pixels square), requiring either downscaling or tiling of larger raster images. Garmin hasn’t issued any tools for creating, managing or uploading such raster maps; you have to use either Google Earth or one of the many 3rd-party tools that have popped up to aid in creating raster imagery (like G-Raster or Mobile Atlas Creator). You’re limited to 100 active map segments in total on your unit; since you can’t turn raster image files on and off, that means a total of 100 map segments is all you can have. And you can’t have different types of raster imagery, say aerial photos and topo maps, for the same area; since you can’t turn one type off while leaving another on, only one type can be displayed. The Magellan Triton is far superior in this respect; raster images can be up to 18000 x 18000 pixels in size, you can put as many into your unit as you have memory for, and you can turn raster image mapsets on and off at will. In order for this capability to be fully functional, Garmin needs to:

– Increase the total number of map segments that can be active

– Give you the ability to turn raster mapsets on and off.

Sample raster map (USGS topo in this case):

raster

Memory: The 450t comes with 1 GB of built-in memory, and the ability to add 4 GB of additional memory with a microSD card that fits into a slot behind the batteries. With the current limitations on raster maps, 5 GB is more than enough space; if Garmin fixes those issues, then I can see where this might not be enough storage space. However, memory cards are cheap and easy to swap out, so that’s not a big problem.

3D View: With a built-in elevation basemap for the US, the Oregon 450t can give you a 3D view of the terrain; with the built-in compass, it changes the view to match the direction you’re facing in. Initially a very cool feature, but IMO it has limitations that limit its usefulness:

– While it will overlay vector map features on top of the terrain view, they’re not labeled. So, for example, if there’s a hill/mountain in the 3D view, its name won’t be displayed.

– Waypoints and tracks are not displayed in 3D view; without that, 3D View’s utility in navigation is limited (although it will display a navigation track).

– Raster maps are not overlaid

3dview

Waypoints: Maximum of 1000 waypoints, the same as older units. But I think you’d have to work hard to come up with a scenario that requires that many waypoints; you can always download and archive waypoints on your computer for future uploads. The touchscreen interface makes entering the waypoint name a lot faster than with rocker switches.

I was going to complain about the lack of custom waypoint symbols, but Garmin recently added that as a beta feature; now they only need to add support for that in their MapSource and Basecamp software.

Tracks: Far better support for track data than earlier Garmin units. Up to 200 tracks can be saved on a unit, and tracks you save now include time data, useful for geotagging photos. Up to 10,000 points in a track, and if you run over that limit on your current track, the Oregon automatically saves the first part of the track in GPX format, and then truncates the current track to free up room for subsquent track points. See the Oregon Wiki track section for full details.

Custom POIs: I’ve posted about these before; they’re a useful way to store points and related data on your unit without having to use up waypoint space. The Oregon units support these, though they annoyingly hide them in the Where To => Extras folder; what’s up with that name, Garmin? Older Garmin units limited POI names to 40 characters, and associated data to 80 characters; Oregon units increase those to 1023 characters, and add some extra data fields (Oregon Wiki has full details). Using the techniques in this post, and taking advantage of the extra data space, you could associate several hundred words of data with each POI; this could be very handy for field work.

There are a host of other features that I’ll skip, like geocaching support, calendar, stopwatch, alarm, etc., since these aren’t really relevant to what I’d want to use this unit for: navigation and data collection. Except for the WAAS issues, which I really hope they fix soon, I found a lot to like in the feature set and basic functions of the Garmin Oregon 450t unit. What I didn’t like, in fact actively dislike, is much of the touchscreen interface; I’ll deal with that in Part II of this review.




Raster Maps For Garmin And Magellan GPS Units, And Mobile Phone Apps, With Mobile Atlas Creator

Mobile Atlas Creator (formerly TrekBuddy Atlas Creator) is an open-source program that downloads map tiles from a variety of sources, and converts them into a large number of formats compatible with mobile phone mapping apps, some Garmin and Magellan GPS units, and OziExplorer. Written in Java, it comes with a Windows executable and Linux shell script to start up the program; I don’t have a Mac, but I’d guess there’s some way to get it to work with Macintosh computers as well. Map sources currently built into the program include:

Continue reading ‘Raster Maps For Garmin And Magellan GPS Units, And Mobile Phone Apps, With Mobile Atlas Creator’




Choosing A Laptop For A Cheap GeoPad

A GeoPad is a field-capable portable PC workstation configured for use with geographic applications (GPS/GIS); see yesterday’s post for more details. The GeoPad website has a full page on what to consider when selecting hardware, and is definitely worth a look. Much of that site is oriented around the purchase of standard field-ready laptops, none of which you could really call cheap. To put together a budget GeoPad, I concentrated on finding one that would meet as many of the following requirements as possible:

1. Relatively inexpensive; less than  $1000, preferably much less.

2. Durable. For standard laptops, 1-year laptop failure rates due to manufacturing defects run at about 10-15%, and 3-year at 15-25% under normal use (up to 31% overall after you factor in “user clumsiness”).  It’s likely that these failure rates would be greater for a laptop that gets jostled in a backpack, or used on a bumpy road. A mil-spec “rugged” PC would be the optimal choice, as it meets US military requirements for shock resistance, temperature, dust, etc.., but these are way too expensive.  A Panasonic Toughbook would be a great choice, but it’s $3000+ for even the most basic configuration. And you have to be careful about the word “rugged”, as there’s no standard definition. For example, the HP Elite 2730P calls itself rugged because it passes the military tests for temperature, dust and altitude, but not the impact/drop tests that reflect the kind of abuse it could see in the field.

3. Touch screen convertible PC. The GeoPad website emphasizes the utility of a touch screen interface for use in the field, and I totally agree. I’ve tried using my Acer Aspire One netbook in the field, with a clamshell configuration, and it just doesn’t cut it. To use it, you have to open it up, and enter data with the keyboard and mouse, something you can’t do standing up unless you have 3+ hands. A touch screen allows two-handed use at a minimum; combine it with a good working tablet case, and you can easily use it without dropping it.

Convertible means that you can use it either in standard clamshell mode, or rotate the screen and fold it down to use it in tablet mode. I wanted the option to use it in standard mode as well as tablet for added flexibility in data entry. You can get “slates”, tablets with no built-in keyboard, and then attach a keyboard via the USB connector; IMO, too clumsy and inconvenient in the field.

4. Good screen visibility in outdoor conditions. Most laptop screens don’t do well in outdoor conditions, especially in direct sunlight; the contrast gets washed out. Some rugged PCs come with special transmissive or transflective screens that will work well in outdoor conditions, but they can be very expensive. To reach my price range, I expected to have to compromise somewhat on this, but still wanted to find one that could be used under some outdoor lighting conditions.

5. Windows OS, because of the larger selection of free software available under this platform.

6. Respectable battery life; at least 4 hours under normal use.

7. Decent memory; 1 GB RAM, plus at least 30 GB storage space for software and data.

8. Light weight and compact size.

9. Plus as many typical notebook features as possible (USB ports, VGA output, wireless, Bluetooth, webcam, memory card slot, etc.)

The cost restriction narrowed down the field immediately; I couldn’t find a single “rugged” laptop available below $1000. Some standard touch screen laptops are available in that price range, in particular some of  the HP tx2 models which are just under $1000. But HP has the worst record for 1-year and 3-year failure rates in the industry (15% and 25%), and reviews have complained about the mediocre battery life. I was hopeful that some netbook touch screen convertibles might do the job, like the Asus T91 or Gigabyte 1028 series. While not “rugged” laptops, they offer a touch screen, 5-hour battery life, low weight, and fairly low cost ($500-700). But while they’re “touch screen” PCs, they have a drawback that would make them hard to work with in the field. A touch anywhere on the screen of these netbooks, even if it’s an accidental brush by your finger or palm, is registered as an input; if you’re trying to enter data on-screen, this can result in a lot of mistakes and frustration. More advanced tablet PCs get around this problem in one of two ways:

– A “digitizer” mode, where the only input recognized is that from a special stylus pen.

– “Palm rejection”, where the touch screen driver can recognize and reject minor contact from your palm or finger touches, but recognize firm contact.

So these cheap netbooks might not be a good choice because of this touch screen issue. The Hp tx2 models offer the option of being used in either basic touch screen or digitizer mode, but are much more expensive and might not be durable enough; at $1000, it seemed risky to go for this model. I almost gave up on the idea of a cheap GeoPad until, by accident, I found a fairly inexpensive laptop that seemed to meet most of my requirements. But that’s the next post in this series  …




A Cheap “GeoPad” – Putting Together An Affordable Field-Capable GIS/GPS Workstation

Last week, I posted my feature “wish list” for a handheld GPS unit designed for advanced fieldwork by scientists, mappers, technicians, etc.. One step up from that “dream” GPS unit are the mini PDA-like GPS devices / handheld computers already on the market from companies like Trimble, Ashtech, Leica Geosystems and many others. These typically have somewhat larger display screens, usually touch-enabled, and often run Windows Mobile. These can be a good choice for field data acquisition, but also have some drawbacks:

  • The screen size is fine for data acquisition, but can be too small for actual mapping work (both viewing and creating maps)
  • Even the cheapest units will start at over $600; more expensive units can easily run into thousands of dollars
  • The software for data acquisition and mapping is limited by the OS; there’s a lot less available for Windows Mobile than for standard versions of Windows (XP/Vista/7)
  • Windows Mobile isn’t the greatest OS in the world, and development of it has been very slow
  • The software that is available is often expensive
  • Processor speeds tend to be slow
  • Input is often by stylus only, which can be slow
  • Storage space for datasets can be severely limited

One step up (or maybe sideways) from these PDA devices is the concept of a GeoPad, a field-capable full PC running a desktop operating system like Windows XP. I’ve been keeping my eye on these for a while now, as this isn’t a new concept. The University of Michigan’s GeoPad website talks about developing the concept since 2003; they define a GeoPad as:

a rugged Tablet PC equipped with wireless networking, a portable GPS receiver, digital camera, microphone-headset, voice-recognition software, GIS software, and supporting, digital, geo-referenced data-sets.

The advantages of a GeoPad over a PDA-based solution (which the GeoPad site calls a GeoPocket) include:

  • Larger screen area, better suited for mapping, and easier for multiple people to view
  • Full Windows OS, which opens access to all Windows-compatible applications
  • Greater storage space (hard drive or SSD), for more datasets
  • More input options: full keyboard, stylus, mouse/trackpad

But it has disadvantages compared to PDA-based solutions as well:

  • Larger and heavier
  • Shorter battery life
  • Less rugged

But the biggest obstacle to GeoPad adoption might be cost. The GeoPad website lists a number of hardware/software combinations, with costs of about $4000-$5000; while the models are a bit out of data (circa 2007), costs of hardware and software comparable to the ones they list indicate that prices haven’t dropped as much as they have for other computer hardware.

About six months ago, I was asked to figure out whether it might be possible to find a combination of cheap hardware, and free/inexpensive GIS/GPS software, that would let you put together a GeoPad-type system for significantly less than the $4000-$5000 range without sacrificing too much in features. Over the next few months, I’ll be writing a series of posts on how I put together a usable GeoPad system for under $700 in hardware and software costs. It’s not a perfect system;  I’ll point out where it’s deficient, and how to work around some of those deficiencies. But you’ll find some of those deficiencies on expensive systems as well. Overall, my cheap GeoPad does most of what the more expensive systems do, at less than a fifth the cost. And even if you don’t go the cheapest route, hopefully you’ll find some of my experiences useful in putting together a GeoPad system of your own.

PS If you have no interest in this topic, don’t worry; I won’t be focusing exclusively on this. Posts on standard blog topics will continue.




In Search Of The Perfect Fieldwork GPS

So I’ve been following GPS Tracklog’s coverage of the Consumer Electronics Show last week in Las Vegas, and been underwhelmed by the handheld GPS announcements:

  • Magellan announced nothing new.
  • deLorme announced their PN-60 model; while it adds an interface with a Spot Satellite Communicator, the GPS capabilities are essentially the same as with the earlier PN-20/30/40 models.
  • And Garmin announced the Oregon 450 and 450T, which join the Oregon 200, 300, 400, 400T, 400i, 400c, 550, 550T. They all pretty much offer the same GPS functionality with minor option tweaks (electronic compass, barometer, camera, built-in map sets).

At the same time, I keep getting asked by field professionals what the best handheld GPS is for serious field work. I have to tell them that there isn’t a single model currently available that does everything I’d like to see in such a unit, so they have to make some compromises. While professional-grade units are available from Trimble and Ashtech (formerly Magellan Pro), they tend to be much more expensive than consumer units, less rugged, have shorter battery lives, and run Windows Mobile (aack). And while they’re good at data recording, they’re nowhere near as good as standard consumer GPS models when it comes to navigation and map display.

There must be tens of thousands of field workers out there who would be a ready market for a reasonably-priced GPS that met their needs, like geologists, biologists, archaeologists, etc.. I’ve put together a list of what I’d like to see in such a unit; feel free to add your own suggestions in the comments. And it’s not like the requirements are all that difficult to meet; in one form or another, you can find most of the following features already present in at least one commercially-available consumer-grade model.

  1. High-sensitivity, high-speed, high-accuracy GPS chipset.
  2. Galileo/GLONASS support for higher accuracy.
  3. Readout of the Dilution Of Precision, plus a graph that shows you the DOP for the rest of the day so that you can choose times of lowest DOP to get the highest accuracy with your GPS measurements.
  4. A high-gain, omni-directional antenna. Many units these days come with just a small ceramic patch antenna, and tend to have less signal gain and be more orientation-sensitive than the “stubby” quad-helix antennas found on models like the Garmin 60CSx and the Garmin Colorado series.
  5. A decent-sized screen that’s easily visible in direct sunlight. 2.6” diagonal is a bare minimum, 3” is even better. Many recent models have higher resolutions and greater color depth than older models, but sacrifice daylight visibility as a result. I’d rather have a unit with fewer colors and lower resolution that you could use in daylight than a sexy high-tech screen where you can’t see anything on it unless you hold it in the shade with the backlight on.
  6. An easy interface for adding text. If it doesn’t detract from screen visibility, a touch screen is fine, but a slide-out keyboard would work as well.
  7. Buttons with programmable functions. One of the big problems with touch screens is that you sometimes have to dive multiple menu levels into the interface to access a needed function; the ability to call up such a function with a single button push would make life a lot easier.
  8. Decent battery life, at least 15-20 hours.
  9. Rugged and waterproof.
  10. More waypoints, tracks and trackpoints. Some models currently sold allow only 1000 waypoints, and 10,000 trackpoints, to be saved. I’ve never had to have more than several hundred waypoints myself, but I’ve hit my unit’s limit of 20 tracks and 10,000 waypoints many times.
  11. The ability to add your own GIS map data, like point/line/area shapefiles, for display on the unit, preferably with at least some attribute data.
  12. Loadable vector maps, from the manufacturer and/or custom maps created by the user or others.
  13. Raster imagery like topographic maps or aerial imagery, both standard mapsets (like USGS topos) and your own custom imagery.
  14. A tri-axial electronic compass that works regardless of how you hold the GPS.
  15. If you have a tri-axial compass, you have the electronics necessary to determine the angle of orientation of the GPS with respect to the ground. This would be useful for geologists (dip and strike), archaeologists (site maps), geomorphologists (ground slopes), botanists (calculations of tree height using angle), and presumably others as well.
  16. Some means for recording additional data associated with a waypoint. Standard waypoints are limited to about 30 characters in the note field, and expanding that to a larger size to add more info would be helpful; another option would be audio recording capability that’s linked to the waypoing.
  17. A built-in camera with both automatic geotagging, and automatic tagging of the direction the picture was taken in. 5-megapixel minimum, with autofocus and a macro mode for closeups.
  18. Bluetooth NMEA serial output so you can use it with a laptop or PDA.

It’s unlikely that any of the current manufacturers of consumer-grade GPS models will someday decide to create a “prosumer” model with a reasonable subset of the features above. But a guy can dream ….

… and he can also try to put together an affordable field-ready PC with GPS and GIS functionality. More on that soon.




Free Routable Street Maps For Compatible Garmin GPS Units

For many Garmin GPS units, including most handheld models, the only mapsets that currently supports turn-by-turn routing are the City Navigator products, like the $75 City Navigator North America. These are available in two formats, both of which tie the maps to a single GPS unit. In the microSD card format, you install the card into the GPS unit, which means you can only use it in one unit at a time, and you can’t use it in conjunction with other mapsets; in fact, if you upload more maps to the card, you’ll erase the City Navigator maps! In DVD format, you can upload the City Navigator maps along with those from other mapsets, but the DVD maps are tied to a single GPS unit based on its serial number and a registration code – you can’t use them on any other unit, nor can you transfer them to a new unit you might buy to replace the old one.

mkgmap is a program that converts Open Street Map (OSM) data into Garmin-compatible maps, and it has recently added support for turn-by-turn routing. The Free routable maps website offers a convenient way to obtain these routable maps in several different formats.

Continue reading ‘Free Routable Street Maps For Compatible Garmin GPS Units’




G-Raster Updated: Raster Imagery In Garmin Handheld GPS Units

I’ve just released version 1.6 of G-Raster (alternate link if that one doesn’t work), my utility for creating raster KMZ overlays for use in some Garmin handheld GPS units (the Colorado, Oregon and Dakota series). Previous versions only worked with georeferenced imagery, like GeoTiffs,BSB, MRSID and raster imagery with worldfiles. For scanned maps without georeferencing, it’s possible to use free georeferencing software, but some might find that too technical. Starting with the latest version of G-Raster, you can use a scanned map that’s been georeferenced using Google Earth, a less complicated procedure:

  • Load the map image into Google Earth (Add => Image Overlay)
  • Use the map controls to move, stretch and rotate the map image until it lines up with the underlying imagery
  • Save it as a KMZ file
  • Load this KMZ file into G-Raster, which tiles the image and creates a Garmin-compatible KMZ file