Talk:Orthographic projection (cartography)

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[edit] Removing the C++ example

Would there be any objections to scrapping the C++ section? It's a bit off topic, and makes sense to <1% of the audience (myself included, and I understand code and GIS). I thought I'd add it here before doing it myself.+mwtoews 05:53, 11 January 2007 (UTC)

Okay, I've removed the example. Here it is for the very few who would care:

  The following [[source code]] fragment demonstrates this algorithm in [[C++]]:

 // Loop through rows and columns of output image f_xy
 // obtaining longitude and latitude at each (x, y) point.
 for (i = 0; i < rows; ++i)                                                                                        
 {
     for (j = 0; j < cols; ++j)
     {
         // Here, (LON, LAT) is a grid of longitudes
         // and latitudes defined at each (x[i], y[j])
         // in the projection plane.  Determined using
         // the inverse orthographic projection.
         lon_pt = LON(i, j);
         lat_pt = LAT(i, j);
         //
         // Interpolate inside image(LON, LAT)
         bool in_domain = DOM(i, j);
         if (in_domain)
         {
             //////////////////////////////
             // Longitudinal periodicity //
             //////////////////////////////
             double test_lon_pt = lon_pt;
             while (test_lon_pt > lon_max)
                 test_lon_pt -= 2*pi;
             while (test_lon_pt < lon_min)
                 test_lon_pt += 2*pi;
             // In case of while loop overshoot
             if (test_lon_pt > lon_max)
                 test_lon_pt = lon_max;
             if (test_lon_pt < lon_min)
                 test_lon_pt = lon_min;
             lon_pt = test_lon_pt;
             //
             // Pole points might not be defined, so just go to the
             // highest +/- latitutude values available.
             if (lat_pt > lat_max)
                 lat_pt = lat_max;                                                                                 
             if (lat_pt < lat_min)
                 lat_pt = lat_min;
             //
             // Invoke, for example, bilinear interpolation to obtain f(x,y)
             f_xy_pt = bilinear(image, lat, lon, image_rows, image_cols, lat_pt, lon_pt);
             f_xy(i, j) = f_xy_pt;
         }
     }
 }