JiGLE with Terraserver

Suggestions for WiGLE/JiGLE/DiGLE

5 posts • Page 1 of 1

Postby mentat » Thu Feb 21, 2002 12:17 am

I'm trying to build a JiGLE mappack generator for terraserver (arial photos and topo maps). I've figured out the terraserver cgi system, but I need a couple things more to make it work. One is a way to convert UTM to Lat Lon as an equation perferably in a perl script. The other is a way to join large jpegs. I'm been using montage from imagemagick but it doesn't seem to use memory intelligently in windows (in other words it runs out on a machine with over a GB of RAM), I'm going to try it on linux but if that doesn't work does anyone have suggestions for a hardcore jpeg joiner? (Talking in the range of 20000x20000 pixels+ for final picture).

Postby mentat » Fri Feb 22, 2002 4:04 am

I figured out how to put together very large JPEG files and shortly thereafter found that they were impractical to load and view. What are the chances of making a region of one mappack point to another mappack? Ie if you zoom into one part of the map it actually loads another mappack (or image). So then in order to cover 10km at 1 meter per pixel resolution I can spilt the file into 2500x2500 pixel images and only have one or two loaded at a time (which might still be too much (probably 800x600 tiles would work)). Ideally (and yes, this is out there) I'd like to download all 10000 sq km of San Diego County at 1 meter per pixel resolution. (Yes, that would take about 20 GB and I don't really need all of it, just the parts that I have WAPs found in) I can do the same sort of thing just by making a whole bunch of mappacks, but it would be cooler if there was a way to have a large map that overlaid several mappacks. The other thing that I'd like would be to be able to set the dimensions of a mappack in UTM. Especially for the terraserver stuff at 1 meter per pixel it makes things much easier. One corner of an image is at Northing 3,645,200.0 Easting 495,600.0 Zone 11. I then know if the image is 800x600 that the next tile image to the east is at Easting 495,600 + 800 and the next image to the south is at Northing 3645200.0 - 600. Of course if I knew an easy way to convert UTM to Lat Lon I'd be fine too. Just some ideas, this program rocks anyways.

Postby bobzilla » Mon Feb 25, 2002 2:30 am

We will have to do something like this in the future. Once the RiGLE map generator starts reading out of a database instead of flatfiles then it can do state-wide and nation-wide maps. It would be nice if a user could load up a national map and zoom in continually down the county level (providing they had all the necessary mappacks).

Everything in the *iGLE stuff uses lat/long, so if we did have UTM support it would just convert it to lat/long before doing anything with it. I'll put it on the todo list, but if you find the equations send them our way and it should be an easy addition.
-bobzilla - WiGLE.net just a little bit
Image

Postby mentat » Thu Feb 28, 2002 5:48 am

I found something very interesting which doing this whole TerraServer investigation. Check out http://terraservice.net/. There is a .Net / SOAP backend to the TerraServer data. They have topo maps and aerial photos. I don't know enough about SOAP to do anything cool with it yet, but it looks like the functionality is there to put together maps on the fly with zooming and stuff like that.
Looks like the URLs used in the tile script (as downloaded from wigle.net) are no longer valid. Microsoft has a document listing the 'official' URLs for getting tiles from the server:

http://terraservice.net/about.aspx?n=AboutLinktoHtml

Also, the script calls ImageMagick's "convert" with an option "-resize", this is not a valid option in my version of the software, I changed this to "-scale" and it seems to work?

I had similar trouble with "montage" to the memory issue you mention. It works fine (and fast) on a Sparc with lots of RAM, but freezes on a PC running BSD with 64Mb.

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