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Creating a depressionless raster (Sinks and Fill)

WesKing

I have run through determining an appropriate z limit for the Fill tool according to the help section..."Creating a depressionless DEM".

Following the steps outlined in the above help section, my output raster for the area I'm analyzing has a range of 6.10352e-005 to 0.680298

The help section seems to stop short of explaining how an appropriate z limit can be derived from the above process.

From the results I obtained above, what is an appropriate z limit? Is it the max or the mean of the range, or maybe something totally different?

Thank you in advance,
Wes

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bump

I currently am having the exact same problem.

curtvprice

Letting the z_limit default is probably what you want to do, unless you are working in unusual terrain or are trying to do something specialized like identifying non-contributing areas (say, playas) based on topography.

The z-limit is used to allow removal of shallow sinks and preservation ones that are deeper than the z-limit. What an appropriate value is would depend on what exactly you are trying to accomplish with the fill operation.

LindaJohansson

Hi everyone!

Has this problem been solved? I am trying to identify natuaral sinks in the terrain. Using ArcGIS 9.3 I am able to fill some of the sinks, by specifying a Z limit. It doesn't work in ArcGIS 10.0.

Thanks in advance!

/Linda

WesKing

Hi Linda,
You may want to take a look at this other post on Z limit problems in Arc 10

http://forums.arcgis.com/threads/31888-Hydrology-Flow-Direction-tool-output-quot-incorrect-quot-when-setting-z-limit

I never got a direct answer to my question in the post you replied to, but maybe you're having issues I posted in the link I provided.

Hope this helps,
Wes

curtvprice

I never got a direct answer to my question in the post you replied to, but maybe you're having issues I posted in the link I provided

Linda, have you updated to SP4 or SP5?

NIM069368 (reportedly fixed in 10.0 SP 4)
When running the Spatial Analyst > Hydrology > Fill tool and specifying a Z limit,
ArcGIS Version 10 SP2 fills less sinks than ArcGIS Version 9.3.1 SP2.

LindaJohansson

Dear all

I have now installed sp4 and it works! Thanks to all of you for your valuable help!

I still have some problems with the lakes. Due to errors in the DEM I get a lot of smalls sinks here. When filling up these sinks I get larger sinks (like the lakes) and their watersheds are very large. However, I just want to get small natural sinks where the water can accululate and where the stormwater network needs to be improved.

Do you use to remove lake areas before the analysis or give the cells in the lake the same elevation?

/Linda

AliAmeli

Dear All
The fill tool is not working for my case (ARCGIS 10.1) Even when I let the default value of Z-limit. No sinks have been filled since the number of sinks before and after applying fill are the same. Not that I have a sloppy domain (13%).
Any suggestions?
Thanks
Ali,

PaulLohr

Curtis,

If it is the case that normally we shouldn't need to determine the Z limit, perhaps it would help to have this added to the help page linked below?

ArcGIS Help (10.2, 10.2.1, and 10.2.2)

curtvprice

the way to get that added is to suggest it by visiting the help page by selecting the feedback link. This feedback goes directly to the Esri help article author -- I've seen them respond to many of my suggestions...

curtvprice

Make sure you aren't resampling your data (for example, make sure the extent, snap raster, cell size, and coordinate system are not set (or at least not set to something different than the input raster.

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