Unity code snippet to save terrain splatmap as texture asset

        data = terrain.terrainData;
        int w = data.alphamapWidth;

        float[,,] splatmapData = data.GetAlphamaps(0, 0, w, w);
        Color[] mapColors = targetTexture.GetPixels();

        int numSplatMaps = splatmapData.GetLength(2);

        for (int z=0; z<numSplatMaps; ++z)
        {
            for (int y=0; y<w; ++y)
            {
                for (int x=0; x<w; ++x)
                {
                    mapColors[x*w + y][z] = splatmapData[x,y,z];
                }
            }
        }

        targetTexture.SetPixels( mapColors );
        var bytes = targetTexture.EncodeToPNG();
        File.WriteAllBytes(Application.dataPath + "/"+targetTexture.name+".png", bytes);