int mapCRS2MINI(const vtProjection &proj)
{
const char *crsname=proj.GetAttrValue("PROJECTION");
if (proj.IsGeographic()) return(1);
else if (proj.GetUTMZone()!=0) return(2);
else if (EQUAL(crsname,SRS_PT_MERCATOR_1SP)) return(3);
return(0);
}
bool WriteTilesetHeader(const char *filename, int cols, int rows, int lod0size,
const DRECT &area, const vtProjection &proj,
float minheight, float maxheight,
LODMap *lodmap, bool bJPEG)
{
FILE *fp = vtFileOpen(filename, "wb");
if (!fp)
return false;
fprintf(fp, "[TilesetDescription]\n");
fprintf(fp, "Columns=%d\n", cols);
fprintf(fp, "Rows=%d\n", rows);
fprintf(fp, "LOD0_Size=%d\n", lod0size);
fprintf(fp, "Extent_Left=%.16lg\n", area.left);
fprintf(fp, "Extent_Right=%.16lg\n", area.right);
fprintf(fp, "Extent_Bottom=%.16lg\n", area.bottom);
fprintf(fp, "Extent_Top=%.16lg\n", area.top);
// write CRS, but pretty it up a bit
OGRSpatialReference *poSimpleClone = proj.Clone();
poSimpleClone->GetRoot()->StripNodes( "AXIS" );
poSimpleClone->GetRoot()->StripNodes( "AUTHORITY" );
char *wkt;
poSimpleClone->exportToWkt(&wkt);
fprintf(fp, "CRS=%s\n", wkt);
OGRFree(wkt); // Free CRS
delete poSimpleClone;
// For elevation tilesets, also write vertical extents
if (minheight != INVALID_ELEVATION)
{
fprintf(fp, "Elevation_Min=%.f\n", minheight);
fprintf(fp, "Elevation_Max=%.f\n", maxheight);
}
if (lodmap != NULL)
{
int mmin, mmax;
for (int i = 0; i < rows; i++)
{
fprintf(fp, "RowLODs %2d:", i);
for (int j = 0; j < cols; j++)
{
lodmap->get(j, i, mmin, mmax);
fprintf(fp, " %d/%d", mmin, mmax);
}
fprintf(fp, "\n");
}
}
// create a transformation that will map from the current projection to Lat/Lon WGS84
vtProjection proj_llwgs84;
proj_llwgs84.SetWellKnownGeogCS("WGS84");
OCT *LLWGS84transform=CreateCoordTransform(&proj,&proj_llwgs84);
// write center point of the tileset in Lat/Lon WGS84
// this is helpful for libMini to compute an approximate translation
double cx=(area.left+area.right)/2;
double cy=(area.bottom+area.top)/2;
if (LLWGS84transform->Transform(1,&cx,&cy)==1)
fprintf(fp, "CenterPoint_LLWGS84=(%.16lg,%.16lg)\n",cx,cy);
// write north point of the tileset in Lat/Lon WGS84
// this is helpful for libMini to compute an approximate rotation
double nx=(area.left+area.right)/2;
double ny=area.top;
if (LLWGS84transform->Transform(1,&nx,&ny)==1)
fprintf(fp, "NorthPoint_LLWGS84=(%.16lg,%.16lg)\n",nx,ny);
// delete Lat/Lon WGS84 transformation
delete LLWGS84transform;
// write CRS info
// this is helpful for libMini to easily identify the coordinate reference system
// supported CRS are: Geographic, UTM, Mercator
const int crs=mapCRS2MINI(proj);
const int datum=mapEPSG2MINI(proj.GetDatum());
const int utmzone=proj.GetUTMZone();
fprintf(fp, "CoordSys=(%d,%d,%d)\n",crs,datum,utmzone);
if (bJPEG)
fprintf(fp, "Format=JPEG\n");
else
fprintf(fp, "Format=DB\n");
fclose(fp);
return true;
}