SRTM3 data (.img format w/index) for a basemap is slow, so to speed up our draw times I'm using a script to make smaller tiles of this data. My script writes the images to .tif format and works, but I also need to generate tiff world files to maintain spatial reference. The definition I found for the .tfw format is:
<br><br>First row is x-pixel resolution<br>
                Second and third rows are "rotational components"
                but are set to zero in the case of an unrotated map.<br>
                The fourth row is the y-pixel resolution. The negative sign
                indicates that the image y-axis is positive down which is the
                opposite from real world coordinates.<br>
                The 5th and 6th rows are the Easting and Northing of the upper left pixel (0,0 in image coordinates)<br><br>So for SRTM3 data which is 90m resolution I am creating a .tfw file like:<br><br>90.00<br>0.00<br>0.00<br>-90.00
<br>???<br>???<br><br>The last two rows are confusing me. Do I need to calculate the pixel position of the upper left corner of each new tile with respect to the pixels of ALL SRTM3 files? That calculation could be problematic.
<br><br>Also if there is another tiling solution that maintains spatial reference I'm all ears. Thank you.<br>