Lat Long image ?

Aug 4, 2006 at 4:56 PM
Hi,

I'm new to sharpmap (found it great so far) and would like to display some WGS84 lat/long data using wms. However the image I get is projected (Plate Carrée projection ?).

Is there a way to get a non-projected image ?

Thanks.

Benjamin.
Developer
Aug 4, 2006 at 7:14 PM
How would you avoid getting something that is on a round surface to be displayed on a flat surface without using a projection?
In other words... as long as you only have 2D available the earth will always display projected from 3D to 2D.
Aug 7, 2006 at 9:56 AM
Not sure if I explained well my problem ...

Lat/Long are figures as well as X/Y projected cartesian coordinates. I don't know why I could not draw a shape using lat/long as "projected coordinates".

For example, I use Mapserver (WMS) to display data from a shape file (lat/long). The image I get is not projected -> It's a bit flattened (larger as it should) but I get an unprojected image.

Actually, I post the exact same WMS query to sharpmap and the image I get back is different (!!).

Watch the differences :

http://simon.benjamin.free.fr/mapserv.png
http://simon.benjamin.free.fr/sharpMap.png

data is in GWS84 and my WMs query is :
REQUEST=GetMap&SERVICE=WMS&VERSION=1.3.0&BGCOLOR=0xAAAAAA&LAYERS=cr_trafic&STYLES=&FORMAT=image/png&CRS=EPSG:4326&BBOX=2.2,48.7,2.45,49&WIDTH=256&HEIGHT=256&reaspect=false


Thanks for your help.
Benjamin.
Developer
Aug 7, 2006 at 10:48 AM
I think this relates to the fact that you request an image of size 256x256 (ratio 1:1) but your boundingbox is 0.25:0.3 (ratio 1:1.2).
Mapserver stretches the image to fit the ratio - SharpMap fits the boundingbox to a ratio corresponding to image size.
Note: Both Mapserver and SharpMap projects your data to Pseudo-Plate Carrée, so you get your data projected either way.
Developer
Aug 7, 2006 at 10:50 AM
This discussion has been copied to Work Item 1677. You may wish to continue further discussion there.
Developer
Aug 19, 2006 at 9:56 AM
This issue is now resolved. Please check with the newest source-release that this also resolves your problem.