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Seeing Russia From Alaska

Published at October 12, 2008 in Google Maps and cartography. 0 Comments

Vice-presidential candidate Sarah Palin has cited the proximity and visibility of Russia from Alaska as evidence of her foreign policy experience:

The HeyWhatsThat website, which lets you determine what areas and peaks are visible from any point on the globe, has a new subpage that spotlights the visibility of Russia from Alaska. 8 placemarks are plotted in a zoomable Google Maps interface, five from the western tip of Alaska and three notable points from the rest of the state: Juneau, the state capital; Wasilla, the town Palin was mayor of; and Denali (aka Mt. McKinley), the highest spot in the United States. Click on any placemark, and the areas visible from this point are highlighted in red (Denali in the example below):

Map of Russia visibility from Alaska



Updates On The Garmin 1:24K US Topographic Map Front

Published at October 7, 2008 in GPS and Garmin. 1 Comment

Garmin continues to slowly add more and more states to their vector-based 1:24K US topographic map coverage. The latest release covers the central mountain West, Colorado and Utah, joining sets for Washington and Oregon as well as California and Nevada . These are in addition to their previous sets for US National Parks in the East, Central and West US; their websites says that maps for the rest of the US are “Coming Soon”. These Garmin 1:24K topo mapsets have some useful features, like elevation profiles, points of interest, routing on trails and dirt roads, and overlays for USGS topo quad and Township-Range-Section information. But at $100 list price ($80 street) for each set, it’s going to get pretty expensive to own even a small number of these. And since they’re being issued on microSD cards, they can only be used on one Garmin GPS unit at a time.

Fortunately, Dan Blomberg at the GPS File Depot, the MiscJunk website, and others continue to release their own versions of 1:24K topographic maps. While they don’t have all the fancy features of the Garmin sets, they’re free, based on the same US Government data as the Garmin maps, and can be uploaded to as many Garmin units as you like. Since my last update, Dan has released new 1:24K topo mapsets for New Mexico and Hawaii, and Idaho is coming soon; there’s also a new transparent overlay for Wyoming land usage/ownership. From the forum on his website, others following the process laid out in his tutorial on making Garmin topo maps are working on similar mapsets for Washington, Missouri and Florida as well. Dan has a list of links to all currently available free 1:24K Garmin topo mapsets at this link; currently, mapset links are listed for AZ, NM, CA, UT, CO, WY, MT, HI, MA, and MS. Maine is also available, but a link to that mapset is missing for now on Dan’s list.

And if you want actual USGS topo maps on your Garmin GPS unit, as well as other raster imagery, there are options …



A Basic Raster Image GeoMetaData Extractor/Viewer

Published at October 6, 2008 in GIS, coordinate conversion and software. 1 Comment

Many raster image formats commonly used in GIS applications have metadata embedded in them that georeferences the pixels (assigns them a coordinate location), and often includes other information like the coordinate system, origin, and datum. Some GIS programs will let you view some or all of this metadata, others won’t. I’ve written a simple GUI front-end program for the GDALInfo utility that will extract the metadata from a compatible image file, display it, and save it in a text file. Download the program folder here, and unzip it to your desired location; keep the executable and the GDAL subfolder in the same folder, otherwise the program won’t work. No installation required, just run the program. Choose the raster image file you want with the “Open File And Read MetaData” button:

Continue reading ‘A Basic Raster Image GeoMetaData Extractor/Viewer’



Displaying Datasets In The Google Earth Plugin With Earth Atlas

Published at October 3, 2008 in Google Earth and KML. 0 Comments

Bjorn Sandvik, creator of the Thematic Mapping Engine for generating thematic prism/choropleth/bar/proportional symbol KMZ files, has just announced the first version of his Earth Atlas, an augmented viewer for the Google Earth plugin (Windows only for now). A tile on the right lets you choose one of 6 internal thematic demographic datasets to display in the globe, or two external ones (icecover and recent earthquakes). But you also have the option to enter the URL for multiple external KML or KMZ file, and have them added to the display as well. Here’s an external KML file from the Google LatLong blog showing photo overlays of flooding in the Kosi River region in India:

Google Earth plugin display with Earth Atlas

Note: you may have to manually scroll to the area covered by an overlay to see it.

In his announcement, Bjorn says “…to be continued!”, and based on his improvements to the Thematic Mapping Engine since its original release, that probably means a lot more capabilities will be available soon.



Another US Demographic Data Site

Published at October 2, 2008 in data. 0 Comments

Mineful.com offers web survey, forms and marketing analytics software and services, but they’ve also just added a new section with free demographic data tabulation and visualization for the United States, broken down by state, county, zip code, and many demographic parameters (age, education, ethnicity, employment, marital status, etc.).

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Unfortunately, the data isn’t downloadable. But for a quick overview of basic demographic data, it does the job. Jaime Brugueras of Mineful, who sent me the link, says that they’re working on additional capabilities for the site like search, radius profile, and more geography types.



Update To Google Earth Position Application

Published at October 1, 2008 in Google Earth. 0 Comments

Last week, I posted on David Tryse’s Google Earth Position application for Windows, which can capture and save the geographic position in the center of the Google Earth view window. The biggest issue with the application is that it was difficult to figure out how to place a geographical object exactly at the center of the Google Earth window, since there’s no crosshair or marker in the application to indicate where it is. I linked to a KMZ file that places a crosshair at the Google Earth screen center, but that’s no longer necessary. The latest version of Google Earth Position now has the option to add such a crosshair to the screen. After starting the program, just right-click on it, and select the Show Crosshair option:

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This will open up a crosshair screen overlay in Google Earth, at the center of the screen; this is the position displayed/captured in the Google Earth Position app:

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Non-Windows users can use the KML link described in this post, or this one suggested by Maarten in comments (though I’ve had problems getting  it to work).



Uploading .img Map Files to A Garmin GPS Unit With IMG2GPS

Published at September 30, 2008 in GPS and Garmin. 1 Comment

An earlier post covered MapUpload, a free program for uploading .img files to a Garmin GPS; another option for this operation is IMG2GPS. This is actually a limited front-end to the command-line program SendMap (included in the IMG2GPS install package), but it supports most of SendMap’s upload features you would normally use.

img2gps

You don’t select .img files for loading into the selection list individually; instead, you specify a folder using the “Load Folder” button, and all .img files in that folder are automatically added to the list. Selecting another folder will add those .img files, while not erasing the ones already there. To erase all the files in the list, click the “Clear” button at the bottom; this clears all the files in the list, regardless of whether they’re selected using the check box. You can save a list of selected files with the “Save” button, and load that list with the “Load” button; it also supports the .gdb format created by MapSource. Finally, you can search through the list of files for a text string in either the filename or the map name using the “Search” function at the top.

To upload one or map files to your GPS, select them with the check box, make sure your GPS unit is turned on, and click “Upload to GPS”. In “Auto” mode, the program should automatically detect a connected GPS, running through all the options (USB and all COM ports). If the program has difficulty recognizing that you have a GPS connected, you can use the “Test Connection” function at the top to help diagnose the problem; you can also manually specify the I/O port your GPS is hooked up to. You can also set a mapset name label for all the maps being uploaded by checking the box below, and entering the desired label.

Unlike MapUpload, IMG2GPS supports uploading to a data card (like a microSD card) in a card reader, which can be faster if the card reader is USB 2.0 (most Garmin GPS units are USB 1.1). Oddly, it doesn’t seem that you can do it directly using the “Folder/Card” option for I/O Port. Instead, you have to combine all of the selected maps into a single “gmapsupp.img” file, and then upload that file to the “Garmin” folder on the data card (see this post for more info on the “gmapsupp.img” file). To do this, check the box at the bottom marked “Create File instead of Upload”; this will change the button below to “Create File”. Press the button, and then select the “Garmin” folder on the data card to save the “gmapsupp.img” file in (create the folder if it’s not already there). When you put the card back into the GPS, the “gmapsupp.img” file will be recognized and read as a map file.

There’s another front-end for Sendmap called GPS Send Map, but it’s obsolete, doesn’t appear to be in development anymore, and doesn’t have the features that IMG2GPS  has.



GISVM - A Virtual Ubuntu Linux GIS Workstation

Published at September 29, 2008 in GIS and software. 6 Comments

GISVM is a Ubuntu 8.04 Linux distribution packaged as a virtual machine, an OS that can be run in a window inside of another OS like Windows, Mac OS X, or even another Linux distribution. It contains a number of open-source GIS packages already installed, including:

  • uDig
  • gvSIG
  • Kosmo
  • FWTools / OpenEV
  • MapServer
  • PostGIS

It’s a big 1 GB RAR file download that decompresses into 3 GB; if you don’t have a program that handles RAR compression, try the free program 7-Zip. To run the virtual machine, you’ll need to install either the VMWare Player or VirtualBox; I’d recommend the latter since it’s been released as open source by Sun, and also doesn’t require registration for the download. Players are available for Windows XP/Vista, Mac OS X and Linux for both platforms. Since you’ll be running two operating systems simultaneously, the demands on your computer can be significant. I wouldn’t run it in less that 1 GB of RAM for Windows XP or Linux, and 1.5 GB for Vista or Mac OS X.

From VirtualBox, use the Virtual Disk Manager in the File menu to Add the decompressed vmdk file to your list of hard disks:

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Then create a New Virtual Machine using Virtual Box’s wizard. Choose Ubuntu as the OS:

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In subsequent dialog windows, give it as much RAM memory as you can spare, and select the vmdk hard disk image as the Existing hard drive. Once you’re done, click on the Start button and the GISVM will open up in its own window, like the one below running on my Windows Vista system:

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One thing you’ll discover quickly is that as soon as you click or type anywhere in the virtual machine window, all mouse/keyboard input is confined to the virtual window, and you won’t even be able to move the mouse cursor out of that window. Pressing the right Ctrl key on your keyboard will release this control, so that you can access your regular OS with the mouse/keyboard again. The infoGISVM*.txt file in the upper corner is worth a look, since it contains basic information about the installed programs, and the basic user passwords.

On my computer system (2.4 GHz Quad Core, 3 GB of RAM, 1 GB assigned to GISVM), the virtual OS machine is very responsive, and programs open up almost as quickly as they do running natively. Here’s qQIS in the virtual machine window:

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I would have liked to play around with it a bit more, but I ran into a major issue: the largest screen resolution you can get in this virtual machine is 800 x 600, and it seems to be impossible to add additional resolutions. This might be a hardware-related issue, but I don’t think so, since the screenshots on the GISVM website also appear to be in this resolution. I haven’t run in 800 x 600 in 12 years, and I’m not about to go back to that now.

I’ve run into this problem before with Ubuntu 6 and 7, where you’re limited in your selection of screen resolutions if you’re running it as a virtual machine or on a remote machine using VNC with no monitor attached. It’s pretty retarded that this is still a problem in Ubuntu 8.04, and IMO another sign that Ubuntu isn’t ready yet for real people. Don’t tell me it can be fixed in the xorg.conf file; A, it can’t (I’ve tried), and B, regular non-techie users shouldn’t have to try to sudo fix this problem in an arcane text file.

If you can live with an 800 x 600 screen resolution, and want to try out Linux apps from Windows or Mac, GISVM is worth a look. If not, I’d wait until a version comes out that supports larger virtual screen resolutions.



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