Mislukt om Generate CNGrid uit te voeren

Question

<\/HEAD>Hallo! <\/P> Ik ben fouten tegengekomen tijdens het genereren van de CN-grid zoals Mislukt om uit te voeren (Generate CNGrid)<\/STRONG>. Maar toen ik de attributentabel van de samengevoegde landgebruik- en bodemgegevens opende om te controleren of ik iets had gemist, is er een toegevoegde kolom voor CN met een waarde erin. Kan iemand alstublieft uitleggen wat dit betekent? Kan ik dit resultaat vertrouwen en gebruiken? <\/P>Hartelijk dank.<\/P><\/P>Met vriendelijke groet, <\/P>Florence<\/P><\/BODY><\/HTML>

renzsamonte · Answer

Ok thank you very much.

On Friday, 9 November 2018, 12:19:08 AM GMT+8, Kurtis Baron <geonet@esri.com> wrote:

#yiv4709837889 * #yiv4709837889 a #yiv4709837889 body {font-family:Helvetica, Arial, sans-serif;}#yiv4709837889 #yiv4709837889 h1, #yiv4709837889 h2, #yiv4709837889 h3, #yiv4709837889 h4, #yiv4709837889 h5, #yiv4709837889 h6, #yiv4709837889 p, #yiv4709837889 hr {}#yiv4709837889 .yiv4709837889button td {}

|

GeoNet

|

Re: Failed to execute Generate CNGrid

reply from Kurtis Baron in Hydro - View the full discussion

It's OK to manually encode the CN values where necessary.

I don't know what the Longest flowpath error issue is.  Could be an issue with different versions of ArcGIS, Arc Hydro, Python, or something in the registry.  You might have to digitize your own flowpaths based on contours, but then you might get hydro ID messages or other errors.  Maybe someone from Esri's Arc Hydro group will chime in...

Reply to this message by replying to this email, or go to the message on GeoNet

Start a new discussion in Hydro by email or at GeoNet

Following Re: Failed to execute Generate CNGrid  in these streams: Inbox

This email was sent by GeoNet because you are a registered user.

You may unsubscribe instantly from GeoNet, or adjust email frequency in your email preferences

KurtisBaron · Answer

It's OK to manually encode the CN values where necessary.

I don't know what the Longest flowpath error issue is.  Could be an issue with different versions of ArcGIS, Arc Hydro, Python, or something in the registry.  You might have to digitize your own flowpaths based on contours, but then you might get hydro ID messages or other errors.  Maybe someone from Esri's Arc Hydro group will chime in...

renzsamonte · Answer

Mr. Kurtis,

Thank you very much Mr. Kurtis for your clear explanation. I appreciate it very much. I attached here is the result of the CN generation. In the first figure, there is no CN grid in the Table of Contents but there is value when I click the "Identify" icon on the merged polygon of soil and land use. The figure below the attachment is the attribute table of the merged polygons showing the added column for CN. Is it alright if I manually encode the CN values wherever it is necessary?

Sir, I hope you don't mind if I share with you another concern and it is about the Longest Flowpath. I always get errors even if I followed carefully the procedures. Thank you very much.

Florence

On Thursday, 8 November 2018, 12:13:52 AM GMT+8, Kurtis Baron <geonet@esri.com> wrote:

#yiv3292065671 * #yiv3292065671 a #yiv3292065671 body {font-family:Helvetica, Arial, sans-serif;}#yiv3292065671 #yiv3292065671 h1, #yiv3292065671 h2, #yiv3292065671 h3, #yiv3292065671 h4, #yiv3292065671 h5, #yiv3292065671 h6, #yiv3292065671 p, #yiv3292065671 hr {}#yiv3292065671 .yiv3292065671button td {}

|

GeoNet

|

Re: Failed to execute Generate CNGrid

reply from Kurtis Baron in Hydro - View the full discussion

Florence,

The way we’ve made curve number grids is to make a lookup table that has a column for land use and a column for hydrologic soil group (A, B, C, or D), and CN.  So, for a particular land use and a particular soil group you decide on a curve number based on the literature.  When you generate a curve number grid the software looks at the land use grid, and looks at the soil group, and finds the curve number associated with those two variables in the lookup table and assigns the value it finds to the output CN grid for all cells in the grid extent.

You could therefore use the Identify tool to click on cells in your watershed and look at the values for all layers: land use grid, soil group grid, and the output CN grid, and see if the lookup table value for that land use and soil group matches the value in the output CN grid.

I noticed there’s some videos online when I searched for how to make a curve number grid.

Kurt

Reply to this message by replying to this email, or go to the message on GeoNet

Start a new discussion in Hydro by email or at GeoNet

Following Re: Failed to execute Generate CNGrid  in these streams: Inbox

This email was sent by GeoNet because you are a registered user.

You may unsubscribe instantly from GeoNet, or adjust email frequency in your email preferences

cn grid results.docx

longest flow path error.png