COMPOSITE CURVE NUMBER CALCULATION

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COMPOSITE CURVE NUMBER CALCULATION

Postby bpierce » Tue Apr 29, 2008 6:17 pm

I have a drawing with defined runoff layers with specified land uses (using closed polylines on specific layers) and a subcatchment boundary. I have no tin surface, nor do I want to generate one for the site. Is there a quick way to have Carlson generate a subcatchment report for me that tells me the area of each land use is within my predefined subcatchment?

It seems that the watershed commands want me to have a site with a tin so that it can create the watershed boundaries for me automatically. I dont always have topo data to make a tin with but I would like the program to be able to quickly summarize land use within a specified area.

Is there an easy way to do this?

Let me know.

Brian
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Postby TerryS » Thu May 08, 2008 3:30 pm

While it may not be the ideal solution, I would create one big flat fake TIN just so that the function will run.
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Re: COMPOSITE CURVE NUMBER CALCULATION

Postby kcrawford » Tue May 13, 2008 8:34 am

bpierce wrote:I have a drawing with defined runoff layers with specified land uses (using closed polylines on specific layers) and a subcatchment boundary. I have no tin surface, nor do I want to generate one for the site. Is there a quick way to have Carlson generate a subcatchment report for me that tells me the area of each land use is within my predefined subcatchment?

It seems that the watershed commands want me to have a site with a tin so that it can create the watershed boundaries for me automatically. I dont always have topo data to make a tin with but I would like the program to be able to quickly summarize land use within a specified area.

Is there an easy way to do this?

Let me know.

Brian


Not necessarily a "quick" or "easy" method, but . . .

If you have Civil or Survey, you can use the Area/Layout menu to report Area by Closed Polyline (the PLAREA command). Choose multiple areas, standard or formatted report, and choose whether to label the areas in the drawing. (You can prebuild selection sets using the EDIT/SELECTION SETS menu if you want to select all polylines on a given layer).

Alternately, you can simply do an AutoCAD LIST command and select each polyline which should summarize the areas for you as well. These are in square drawing units, however, and you must convert to acres if that is your intent. Or, do a PROPERTIES on each selected polyline individually. One of the fields in the bottom of the list is the area, again in square drawing units.

And if you plan to move to the 2009 version, the drawing inspector (show polylines) will report area in both sq ft and acres if the polyline you are hovering over is closed. Again, you have to point to each one individually and write down the areas or enter into a spreadsheet as you go along, but the numbers are there.

Best answer is to just compute a quick TIN and have it compute for you. It would, however, be a nice addition to the Define Runoff Layers dialog, just a simple report of areas.
------------------------------------------
Kenneth A. Crawford, PE, QCM
Carlson Software, Training Division
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