Lorsque j'exécute le reconditionnement DEM, certaines cellules deviennent NoData.

Question

<\/HEAD>J'ai d'abord nivelé les plans d'eau, sans problème apparent. Mais lorsque j'ai ensuite exécuté le reconditionnement DEM, certaines cellules deviennent NoData. Pourquoi ? C'est un gros problème. Y a-t-il un moyen d'obtenir le code source du processus afin que je puisse l'examiner et le recoder si nécessaire ? <\/P><\/BODY><\/HTML>

KirstenHazler · Answer

Glad to know it's not just me having the issue.  I have since abandoned the DEM Reconditioning tool and wrote my own algorithm in Python, which runs a modified AGREE procedure.  If anyone wants it, feel free to contact me.

BenjaminJackson · Answer

Hi,

I also encountered this problem and I too noticed that it only changed values of 0 to nodata. So I used a workaround that you might find useful: I ran raster calculator on my DEM and added 0.0000001 to all cells in the raster, this in effect removes 0s whilst effectively retaining them. Then I ran reconditioning on the result successfully.

In effect what I actually achieved was simply to convert the raster, since the precision required to add 0.0000001 is not available. I was using an Integer DEM and the resulting layer is Double precision 64bit. So I would suggest trying to convert the raster first and if that does not work, apply raster calculator with a very small number. Hopefully this will be fixed soon.

KirstenHazler · Answer

Update:  I have figured out that anywhere the input DEM is exactly 0, the reconditioning process returns NoData.  Clearly something is wrong with the algorithm.