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Archive for January, 2010

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.




Merging Raster Imagery With MicroDEM

I use to recommend the TatukGIS Viewer as a good free program for merging raster imagery and export it in georeferenced full resolution, but as last week’s post indicated, the latest version of it drops this functionality. Someone asked me for a recommended free alternative, and for now I’d pick MicroDEM for that. It does have some limitations:

Continue reading ‘Merging Raster Imagery With MicroDEM’




New At HeyWhatsThat: Solar Eclipse Simulator, WebApp For iPhone And Android

I first posted about HeyWhatsThat 2+ years ago; its initial functions included:

  • A panorama of what’s visible from that location, marking the position of peak geographic landmarks
  • A list of the peaks, and the ability to show their position relative to your location on Google Maps
  • Terrain profiles (elevation versus distance from the location to any point on the map).
  • A plot all the areas visible from that location in red on Google Maps (aka the “viewshed” or “weapons fan”).
  • Contour lines.
  • Google Earth export of position, viewshed, horizon line and horizon extent.
  • Mike Kosowsky has been adding functions to HeyWhatsThat since then, and writes to announce two more:

    1. A simulator of Friday’s annular solar eclipse:

    eclipse

    2.  A web app to let you find out what you’re looking at using your iPhone or Android; point your phone’s browser to m.heywt.com.




    Watch Out If You Upgrade To TatukGIS Viewer 2.0

    A few years ago, I had several posts on the TatukGIS Viewer, a free program for viewing vector and raster GIS data. IMO the most valuable feature of this program was the ability to export georeferenced raster imagery of the view, with a great deal of flexibility in the resolution of the final output. Recently, TatukGIS announced a major upgrade to version 2.0 of the Viewer, the main improvement being on-the-fly reprojection of raster/vector data; previously, all the data had to be in the same coordinate system. Unfortunately, after trying it out, I discovered that they have removed the raster export function completely; it’s only available in their GIS editor, which costs $350. It’s still not a bad GIS viewer, but with the loss of this export function, I’d have to say you’d be better off learning how to use one of the free GIS viewers/editors that offer either on-the-fly reprojection, raster export, or both (e.g. gvSIG, qGIS, MapWindow, and many more – check my Big List Of Free GIS Programs posts for more). Plus, with these free/open-source options, you won’t have to worry about features being removed arbitrarily.

    If you still want to try the new version of TatukGIS Viewer, make sure not to select the option that uninstalls the old version, like I did. Fortunately I had an older installer archived, as TatukGIS has removed all links to older versions.




    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.




    Multiple Embeddable Web Maps With Switch Maps

    New from MapChannels is Switch Maps, an easy way to embed multiple web maps in a single frame. A simple web interface lets you set the geographic extents, size of the map frame, and which maps to include:

    Continue reading ‘Multiple Embeddable Web Maps With Switch Maps’




    Topographic Maps For The US And Canada In A Google Maps Interface

    Joseph Elfelt writes to announce his Gmap4 website, which displays the MyTopo version of USGS topographic maps (down to 1:24K scale) and Canadian topo maps (to 1:50K) in a Google Maps interface; standard Google Maps layers are available as well. The initial map window view is pretty small; for a better view, select “Full Screen” from the action menu.  The US topo maps are very high-quality terrain shaded maps, better than Terraserver, and substitute the updated US Forest Service topos where available:

    usfstoposhaded

    The Canadian maps generally look good as well, though they sometimes have issues with border mismatch between tiles, and differences in map lightness:

    canadatopo

    You can also display GPX and KML files on top of the topo maps, like this KML file:

    kmlsample

    The help file, available as a PDF from the “Action” drop-down menu in the upper-right corner, explains how to do this three ways:

    The site is non-commercial and ad-free, to conform to the licensing limitations of the MyTopo API.