[OpenLayers-Users] Calculating Resolutions
Linda Rawson
linda.rawson at gmail.com
Sun Oct 28 21:10:08 EDT 2007
I think I need to do something similar to what this guy has been doing ->
http://trac.openlayers.org/ticket/889 but I am unsure.
What is boils down to is I need the user to see a 600px X 600px map.
The map should be projected in 4326.
The "lat/lon viewport" should be able to be converted to UTM. When
converted to UTM the image should relate to 1200 meters X 1200 meters.
I have these lat/lon coordinates.
ullon = -90.0685495;
ullat = 38.6246312;
lrlon = -90.0552241;
lrlat = 38.6134851;
If I convert to UTM using the formulas here ->
http://www.koders.com/javascript/fid1D029A7E5070579F0F6B6CF3A9115FB82E0AFD69.aspx
zone = Math.floor(((lon + 180) / 6) + 1);
I get the following in UTM
ul 755199.9576653754,4279199.867093539 lr 756400.339594843,4278000.552061474
ULLatUTM - LRLatUTM = 1200
ULLonUTM = LRLonUTM = 1200
But I can never get the map to display this box in the "viewport". I can
never seem to get the resolution right. The closest I can come is 1200 X
1000 meters per pixel. What can I do to return a "square" image?
Thanks,
Linda Rawson
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