sepideh

09-15-2013, 11:46 AM

Anyone interested in rendering geographic data with opengl! please help me

As you know we have two kinds of coordinate systems in GIS : Geographic coordinate systems and projected coordinate systems

consider these situations:

I have a shapefile that has projected coordinate system, I mean the coordinates of the vertexes are in PCS, so there's no problem I can extract vertices with GDAL/OGR library and then show them in OpenGL with orthographic projection. since the coordinates are in meters and they're projected on a 2D plane, there will be no problem I think.

The datasource has a geographic coordinate system and I just want to render it in a projected coordinate system, so I have to do the transformation with PROJ.4 library and then render the transformed coordinates in OpenGL. Again I think there will be no problem, since the coordinates I want to show areb projected on a 2D plane.

The datasource has a geographic coordinate system and I want to render them in the the same GCS on an OpenGL window. So I extract coordinates with GDAL/OGR in geographic coordinate system and without any transformations, I'll render them in OpenGL. How can I achieve this? I mean how can I set up an ellipsoidal plane in an OpenGL window just like ArcGIS does renders data in geographic coordinate system?

As you know we have two kinds of coordinate systems in GIS : Geographic coordinate systems and projected coordinate systems

consider these situations:

I have a shapefile that has projected coordinate system, I mean the coordinates of the vertexes are in PCS, so there's no problem I can extract vertices with GDAL/OGR library and then show them in OpenGL with orthographic projection. since the coordinates are in meters and they're projected on a 2D plane, there will be no problem I think.

The datasource has a geographic coordinate system and I just want to render it in a projected coordinate system, so I have to do the transformation with PROJ.4 library and then render the transformed coordinates in OpenGL. Again I think there will be no problem, since the coordinates I want to show areb projected on a 2D plane.

The datasource has a geographic coordinate system and I want to render them in the the same GCS on an OpenGL window. So I extract coordinates with GDAL/OGR in geographic coordinate system and without any transformations, I'll render them in OpenGL. How can I achieve this? I mean how can I set up an ellipsoidal plane in an OpenGL window just like ArcGIS does renders data in geographic coordinate system?