DEM Reconditioning >> Empty AgreeDEM

RyanLondeen

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Mám problém se zpracováním terénu pomocí ArcHydro.<\/P>

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Verze ArcGIS: 10.2.2<\/P>

Verze ArcHydro: 10.2<\/P>

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Problém: Kdykoli spustím nástroj DEM Reconditioning, dostanu jako výstup prázdný Agree DEM.<\/P>

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Moje kroky:<\/P>

1. Vytvořit projekt ve složce umístěné na mé ploše (bez mezer a relativně krátká cesta k souboru)<\/P>

2. Importovat master DEM raster pro okres<\/P>

3. Importovat síť potoků pro okres (FEMA)<\/P>

4. Vytvořit polygon pro nastavení masky hranice umístění projektu.<\/P>

5. Extrahovat podle masky DEM do hranice<\/P>

6. Oříznout wtr do hranice.<\/P>

7. Vytvořit file geodatabase<\/P>

8. Nastavit rozsahy na vrstvu hranice<\/P>

9. Nastavit cílová umístění na složku úkolu a geodatabase<\/P>

10. Spustit DEM Reconditioning<\/P>

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Dělám v procesu něco špatně?<\/P><\/BODY><\/HTML>

GaneshchandraMallya

Hi Mark:

I was able to successfully obtain the AgreeDEM when I tried it again today.

Here is what I did (mostly following your tips in this thread as well as your popular ArcHydro thread):

1. Use Windows 7 utility Disk Cleanup to empty the Temp folder.
2. Open a new ArcMap document and add the DEM raster and the stream network shapefile.
3. Ensure that both these files (from step 2) have the same projection. In my case it was UTM 15N.
4. Create a folder for the project e.g. C:\MyProject
5. Save the ArcMap document as C:\MyProject\MyProject.mxd. This step generally sets the target locations correctly.
6. Double-check the target locations before running any ArcHydro functions using ArcHydro toolbar -> ApUtilities -> Set Target Locations -> HydroConfig. When you double click the HydroConfig
   • Raster Data should be pointing to C:\MyProject\
   • Vector Data should be pointing to C:\MyProject\MyProject.gdb
   • Map Name = Layers (Layers is the default name of the dataframe in the ArcMap document)
7. Check the processing extent using Geoprocessing -> Environments -> Processing Extent
   • I set the extent as Union of Inputs
8. Clear Temp folder again using ArcHydro toolbar -> ApUtilities -> Addition Utilities -> Clean User's Temp Folder
9. Run DEM Reconditioning to obtain AgreeDEM.

For the sake of any future GIS enthusiasts who encounter a similar error, I thought I will complete the discussion:

In my opinion, the original issue was not likely due to incorrect processing extents because the AgreeDEM (see attached figure from my initial post) did burn the stream network for the entire study area (burnt streams represented as black pixels spread over the study area- figure is at maximum zoom-out level). However, the entire left half (you can observe a vertical demarcation in the AgreeDEM - showing white region with black pixels on the LHS and a shaded region on the RHS of the AgreeDEM) of the study area (except the pixels burnt as stream) had pixels with value=No_Data. You rightly recommended me to check this again as the legend in the figure was showing white areas to be of high elevations (272-592). Though not shown in the legend, I have confirmed that most of the left half of the AgreeDEM had No_Data.

The values in the AgreeDEM appear to be strange at first look because by default the Symbology (or legend) for AgreeDEM was set to be Classified with inverted color coding compared to the input DEM. Further the AgreeDEM was run with the following parameters: Smooth drop in Z units = 100, and Sharp drop in Z units = 1000 to exaggerate the burning of pixels representing the stream. Same parameters were eventually used in the solution.

I am not able to pinpoint the exact cause for this error, except to agree that one needs to be careful while setting up the project and follow the best practices recommended by experts like you. Finally, if everything fails remember not to give up. Seek help. Start fresh.

I want to thank you again for your insights and detailed explanations for probable causes for this error. It was very helpful.

Best.

Ganesh