topic Re: Hydrology Flow Direction tool output "incorrect" when setting z limit in ArcGIS Spatial Analyst Questions

Hydrology Flow Direction tool output "incorrect" when setting z limit

Anonymous User — Fri, 03 Jun 2011 13:58:03 GMT

Original User: wesley.king

ArcGIS v10 sp1, 64 bit Vista:
I've never seen this happen before, but I haven't done a hydrology analysis since installing v10. When running the Fill tool and not setting the z limit (defaulting to fill all), then running flow direction the output is as expected...values of; 1,2,4,8,16,32,64,128. Then running flow accumulation with with directional raster works as expected (see attachment).
BUT
When running the Fill tool and setting the z limit (trying about 8 different values), then running flow direction the output is NOT as expected...cells with values ranging 1-255. Then running flow accumulation with this directional raster results in output that is obviously wrong (see attachment).

Anyone have any idea what's happening?

Thanks in advance,
Wes

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

Anonymous User — Fri, 03 Jun 2011 18:46:36 GMT

Original User: wesley.king

I ran the same tools with the same input (same elevation raster and z limit of .1) in both v10 and v9.3.1 and the resulting flow accumulation is horribly different. See the attachments named according to which Arc version used. The extent for the screen shot is the same, but one is shifted slightly.

The tool order is; Fill > Flow Direction > Flow Accumulation

I'm not sure what to think about this...anyone come across anything similar, or have any ideas?

Thanks,
Wes

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

WesKing — Fri, 03 Jun 2011 18:50:26 GMT

Helps to add the attachments 🙂

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

Anonymous User — Fri, 03 Jun 2011 21:07:50 GMT

Original User: pyadav1

We would like to work with you to understand the problem and troubleshoot it. Could you please contact Technical Support so we can work with you to get a reproducible case? If it is a software defect, our analyst will report it our development team for further investigation. To contact Esri Support, you can either:

1. Go to Support.esri.com > Scroll down > Choose Support Request Form and submit a new request online; or

2. Call 888-377-4575 and have a new call logged with an analyst.

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

WesKing — Fri, 03 Jun 2011 21:47:01 GMT

Thanks Pavan, I just submitted and hope to hear from you soon.

Wes

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

Anonymous User — Wed, 28 Sep 2011 19:42:56 GMT

Original User: rhbricky

Was this ever resolved?

The output from Fill is distinctly different in 10SP2 than in 9.3 (and incorrect)
If I use a layer filled in 9.3, it works just fine. Filling using 10 or 100 gives me the original unfilled DEM as a result.

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

WesKing — Wed, 26 Oct 2011 20:00:23 GMT

Hi Richard,
This issue has not been resolved yet. ESRI was able to reproduce exactly as occurred with my analysis. A software bug report has been sent in by ESRI support services and I haven't heard anything since it was sent in. The reference number for this bug is NIM069368 just so you know.

I searched the fixes in SP3 and didn't see it was included so I'm assuming it will be a while before the fix occurs.

Wes

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

Anonymous User — Wed, 08 Feb 2012 15:55:13 GMT

Original User: pyadav1

Hi Richard,
This issue has not been resolved yet. ESRI was able to reproduce exactly as occurred with my analysis. A software bug report has been sent in by ESRI support services and I haven't heard anything since it was sent in. The reference number for this bug is NIM069368 just so you know.

I searched the fixes in SP3 and didn't see it was included so I'm assuming it will be a while before the fix occurs.

Wes

Hi Wes,
I would like to let you know NIM069368 is in our ArcGIS 10 Service Pack 4 target list. SP 4 is planned to be available next month (March, 2012). I greatly appreciate your efforts to bring this issue to our attention.

Thanks
Pavan Yadav

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

RickThalacker — Wed, 19 Jun 2013 19:36:08 GMT

Has this issue been corrected for 10.1? I am experiencing the same issues using fill tool with z limit set to 1. I am using 1m LiDAR dataset, conversion las to raster, cell size 3m.

I can run the fill tool with z limit default-flow direction-flow accumulation with no problem. If I set z limit to 1, I have the same troubles described in this blog.

Rick Thalacker

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

Anonymous User — Wed, 19 Jun 2013 21:56:00 GMT

Original User: curtvprice

Has this issue been corrected for 10.1?

The bug report says it was indeed resolved in 10.0 SP4 and 10.1. I would take this to support with a small test dataset so they can fix it!

NIM-069368 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.

Status: Resolved
Version Fixed: 10.1
SP Fixed: 10.0SP4

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

RickThalacker — Thu, 20 Jun 2013 16:58:48 GMT

The trouble I am having refers directly to the trouble in the top post.

"When running the Fill tool and not setting the z limit (defaulting to fill all), then running flow direction the output is as expected...values of; 1,2,4,8,16,32,64,128. Then running flow accumulation with with directional raster works as expected (see attachment).
BUT
When running the Fill tool and setting the z limit (trying about 8 different values), then running flow direction the output is NOT as expected...cells with values ranging 1-255."

I not sure this relates to filling fewer cells than previous version of ArcMap.

Rick

ver.10.1 with SP1 installed on machine.

Re: Hydrology Flow Direction tool output "incorrect" when setting z limit

Anonymous User — Sun, 12 Dec 2021 02:36:04 GMT

Original User: curtvprice

When running the Fill tool and setting the z limit (trying about 8 different values), then running flow direction the output is NOT as expected...cells with values ranging 1-255."

This is what I'd expect... if you set a Z limit, some areas are not filled, so there will be sinks remaining when you calculate flow direction. As described in the FlowDirection tool reference, sinks will be coded with values between 1 and 255 (ie non-powers of two) that code which cells flow into the sink. You can easily identify those sink cells using the extract By Attributes tool:

ExtractByAttributes("flowgrid", "flowgrid",
    "VALUE NOT IN (1,2,4,8,16,32,64,128)")

UPDATE: stackoverflow is awesome. Here's an arcpy map algebra way to do it that is just too cool, using the "bitwise and" operator &:

SetNull("flowgrid" != 0 and "flowgrid" < 256 and
    (("flowgrid" & ("flowgrid" - 1)) == 0, "flowgrid")