Why is exported DEM so much smaller than OrthoMosaic?

[nickponline]

I'm exporting my DEM and Ortho using:

blockw, blockh = 4096, 4096

chunk.exportOrthophoto('ortho.tif', blockw=blockw, blockh=blockh, color_correction=False, blending='mosaic', write_kml=True, write_world=True, projection=chunk.projection)

chunk.exportDem('dem.tif', blockw=blockw, blockh=blockh, write_kml=True, write_world=True, projection=chunk.projection)

I get many ortho-x-x.tif images each 4096x4096 but only a single dem.tif which is 4096x4096 and the DEM uses only the top left of this image?

[Alexey Pasumansky]

Hello nickponline,

You can specify the same resolution using the corresponding argument. However, the effective resolution of DEM depends on the reconstruction quality used. While for orthophoto it is usually close to original resolution of photos.

[nickponline]

If you look at my code above you will see that I did specify the same resolution. What settings during the process would effect the resolution of the final DEM.

[Alexey Pasumansky]

Hello nickponline,

You've specified only block size and there's nothing about export resolution (similar to m/pix field in export orthophoto/DEM dialog in GUI).

[nickponline]

Hi Alexey,

Thanks for the reply. Won't it default to the GSD like exportOrthophoto does?

[Alexey Pasumansky]

Hello nickponline,

Default export resolution is different for orthophoto and DEM export (you can check it in the corresponding export dialog). Effective orthophoto resolution is close to the effective resolution of the original images, whereas default DEM export resolution depend on the model reconstruction quality.