Friday, February 17, 2006

Spot, OGC & WMS

Spot is a GPS-enabled software developed by SkyLab originally designed for phones including the Blackberry 7250 model which has an integrated GPS receiver.

I couldn't get Spot, the GPS enabled version to work with the IBM VM J9 in the PocketPC only Spot Viewer, the non-GPS version worked. It wasn't that exciting. SkyLab also has an unsupported midlet called WMSClient that worked just fine with the Motorola i415.

WMSClient is a MIDP 2.0 midlet that can be used as a browser to OGC compliant WMS services, which translated to plain english refers to Open Geospatial Consortium compliant Web Map Servers.

The maps provided (free) by these servers include several layers describing a given area in the world layered one on top of another like those used by GIS applications.


After having the midlet installed to your phone start the app and select Key Setup. This will let you choose the corresponding key values for panning a map with your phone and switching between pan and zoom. Select then new OGC-WMS and type the URL of one of the servers listed on this page.

This will take a while. And you will need to do this everytime because the bookmarks only keep two entries: one for Nasa and another for the USGS server. After you have a sucessful connection to a server you will be presented with a multiple list of checkboxes with options to choose from. Those are the layers available at this particular server.

GPS Simulator

The screen of the i415 isn't that great so if you want to have a better idea about the kinds of data you can get from WMS, check another app developed by SkyLab: GPS Simulator 2 which you can run on a Windows box. You will need Java version 1.4.1 or newer to run it.

If you want to simulate GPS receivers, that is what you get from this app in several different possibilities. But my idea was to use it as a full blown WMS viewer on a PC screen.

Launch the demo version and select the Map Input tab. Hit the WMS Map box and the WMS Config button. This will cause a little dialog to get displayed, select one of the URL's from the drop-down list at the top and hit the Get Capabilities button.

That will ping the server and ask for its capabilities which means something like: "Tell me which layers you have available". Click the ones you want holding the Shift key and when you are done hit "apply". Close the dialog and wait for the download to complete. It might take a while depending on the amount of choices you made.

And you might end up getting a map that is not that useful but which looks kinda cool.

The full version of GPS Simulator costs US$99. Intergraph distributes the source code of a free WMS Viewer that you can run with IIS. You can also run it from a browser (IE 5.0 or Netscape 7.0 or higher). Other choices include the deegreeWMS viewer available at SourceForge and a standalone WMS viewer named Gaia.

No comments: