[Xastir] manually generated tiger map problem

[Jason Winningham]

I'm trying to generate some tiger maps to use when an internet  
connection is not available.  I fired up the sniffer, extracted the  
tiger URL that xastir generates, and wrote a little perl script to  
generate the URLs and (I think) matching .geo files.  Here is a sample  
URL and .geo file:

/usr/local/bin/wget --output-document=t_00.gif  
"http://tiger.census.gov/cgi-bin/mapper/map.gif? 
&on=GRID&on=counties&on=CITIES&on=places&on=majroads&on=railroad&off=sta 
tes&on=interstate&on=ushwy&on=statehwy&on=water&on=shorelin&on=miscell&l 
at=34.05&lon=-86.95&wid=0.1&ht=0.1&iwd=1000&iht=1000"

FILENAME t_00.gif
TIEPOINT 0 0 -87.0 34.1
TIEPOINT 999 999 -86.9 34.0
IMAGESIZE 1000 1000

My problem is that the vertical edges of the maps are off by quite a  
bit.  For the maps that are 0.1 degree square, points that should be on  
the left and right edges are 0.01 (10%) toward the center of the map.   
I have tried square maps from 7.5 minutes to 1 degree square with the  
same results.

The horizontal edges match perfectly.

Is there some mapping magic I don't understand here, or is my .geo file  
wrong, or what?

The tiger maps that xastir generates are, of course, pretty much  
perfect.  The reason I'm not using snapshots as someone suggested  
yesterday is that I need hundreds of them to get the detail I want, and  
copying that many snapshot files is too much effort.

thanks,
Jason
kg4wsv
----------------------------------------
Jason Winningham
Computer Systems Engineer
College of Engineering
The University of Alabama in Huntsville
http://support.eng.uah.edu/	http://www.eng.uah.edu/~jdw