When creating a raster I set the lower-left x/y values, and asc file has
the following "header":
ncols 1731
nrows 1863
xllcorner 17548488.944545675069
yllcorner -8069349.376163828187
dx 500.162987955558
dy 500.081943659035
Note that the raster data is going from bottom to top.
However, now it seems that I need to reorder the raster data so that my
raster data will appear from top to bottom, instead of bottom to top. In
the above case, I want the dy to assume negative value.
What is the best way to do it?
Of course I can do the thing in a manual, hard way, ie:
using (var ds = Gdal.Open(demInputTiff, Access.GA_Update))
{
var nCol = ds.RasterXSize;
var nRow = ds.RasterYSize;
double[] geoTransform = new double[6];
ds.GetGeoTransform(geoTransform);
if (geoTransform[5] < 0)
return; //no need transformation
geoTransform[3] += geoTransform[5] * (nRow -1);
geoTransform[5] *= -1;
ds.SetGeoTransform(geoTransform);
Band band = ds.GetRasterBand(1);
var allValues = new int[nCol * nRow];
var noData = band.NoDataValue();
band.ReadRaster(0, 0, nCol, nRow, allValues, nCol, nRow, 0, 0);
//manual reordering, crude way of iterating through the array
var allValues2 = new int[nCol * nRow];
for (int i = 0; i < nRow; i++)
{
for (int j = 0; j < nCol; j++)
{
allValues2[(nRow - i - 1) * nCol + j] = allValues[i * nCol + j];
}
}
band.WriteRaster(0, 0, nCol, nRow, allValues2, nCol, nRow, 0, 0);
ds.FlushCache();
}
But is there a built-in function for this? Will converting to other formats
like AAIGRID and back and forth correct for the orientation?
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