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Topic: Orthorectification went wrong

Hi there,

I'm using ASTER L1A imagery as a raw file, Landsat ETM+ imagery that is already georeferenced and an ASTER GDEM at 30m resolution, patched together so it matches the whole area of the pictures. I had problems before which where due to the DEM having holes, so the picture came out blurred. i have now succeeded in producing a focused, orthorectified image following the instructions. Or have I? Upon linking the displays i find that the new image is completely out of place. The blurry picture was in the right place. The only thing i changed was taking the Map Grid from the georeferenced picture for blurry result to using the raw images map grid for the good looking but misplaced picture. My instructions however tell me to take the map grid from the raw image, so how can this be?

Any ideas?
Alex

2 (edited by EriolAB 2012-06-11 04:18:46)

Re: Orthorectification went wrong

edit: changing the map grid source back to georeferenced image didn't change anything, except for the image being a bit blurrier again - but still out of place, although elswhere (??)

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Re: Orthorectification went wrong

Hi Alex,

I don't understand what you've done. If the georeferencing of the blurry image was correct, you simply have to orthorectify again you L1A image using the DEM with no hole, and that should work. The georeferencing is only affected by the mapping matrices and the blur is due to the resampling, so mis-registration should not occur. Maybe you changed the georeferencing of your DEM when filling the holes?

Sebastien