Latest Contributions by curtvprice

Markus, I am have never done an implementation of USLE analysis in ArcGIS. I see you found an expert to help you on gis.stackexchange.com - I will quote his answer here for the local USLE fan club: Jeffrey Evans: How to calculate changes in slope angle between cells/areas? The original USLE assumed little slope curvature and no deposition. To account for flow convergence in complex terrain, modifications were made to the LS factor with an equation that incorporates flow accumulation. Because they are now used interchangeably, when you see reference to slope-length most likely it is in reference to the LS factor, as calculated below. To calculate the LS factor for the RUSLE equation, first calculate flow accumulation (facc) and slope in degrees (slp). Then a bit of map algebra in the raster calculator yields LS. Power(facc * cell resolution / 22.1, 0.4) *      Power(Sin(slp * 0.01745) / 0.09, 1.4) * 1.4 One downside of the stack exchange is they do not promote discussion - they just want the answers! So may I ask you, Markus, to follow up the post when you have figured out how to do this. I am especially interested in whether the Curvature tool (which is designed to capture this deposition/erosion factor for modeling) was any use to you in parameterizing USLE. I'm sure the Spatial Analyst team would love to hear what you think, especially if you have a idea on how to improve or complement that tool. ... View more

The geoprocessing extent is set to the extent of your IDW tool inputs by default. If you want the IDW interpolation to cover a larger extent, you need to set the GP extent to include the entire state. After you generate your surface, you can clip your surface to the state boundary using another tool such as Clip_management. ... View more

However, often when I use EQUAL_AREA I also get empty classes.  Can anyone shed light on why this would happen?  Stacie - the problem you are running into here is probably having to do with the distribution of your data. Your data probably has a lot of tied values. For example, consider a small 1 x 10 raster with just these cell values: 10 10 10 10 10 20 20 20 20 20 An equal area slice into two levels would look like this: 1  1  1  1  1  2  2  2  2  2 But what if we asked for three? We can't "split" these groups. So you will probably still get: 1  1  1  1  1 2  2  2  2  2 because of the ties. ... View more

I think you're missing something. The Calculate Value tool I wrote for you takes the output of the Merge (the precondition connect just makes the merge happens first) and modifies that table. The CV output should then go to the your export tool (make sure it is set to type TABLE  so it will be accepted by the tool!)  The merge output should not be connected to your export tool. ... View more

Douglas - I suspect a path name issue. What's in the variable tmpGrid? What is the current and scratch workspace set to? (See [thread=48475]How to post Python code[/thread]) ... View more

I'm trying to create a script tool but when I run the tool I keep getting and error message: I'm not sure what the problem is with the  df = arcpy.mapping.ListDataFrames(mxd)[0] Your mxd variable wasn't successfully set to a map document object, it's a unicode string (ie the path to the mxd as a text string). Try changing this mxd = arcpy.mapping.MapDocument = arcpy.GetParameterAsText(0) to this mxd = arcpy.mapping.MapDocument(arcpy.GetParameterAsText(0)) ps Please follow [thread=48475]these instructions[/thread] to post/edit Python code in the forum. ... View more

You need to use preconditions to control the order of processing. Your merge must run first before the Calculate Value so the "Output Table" dbf will have been created before the CV starts. The output of your Calculate Value is a table -- which you then want to provide as input to your export to Excel function. Hope this helps. [ATTACH=CONFIG]23043[/ATTACH] ... View more

I got this command line to run.  But the .tifs failed to load into the SDE Raster Catalog.  Without error messages, I wouldn't have a clue. Note that Workspace to New Raster catalog assumes the catalog does not exist yet.  If you're running into trouble, I recommend going back to the help and following the instructions carefully so you are certain you are making the right flavor of raster catalog for your needs. You also may want to test with a small number of rasters loading to a file geodatabase. I am not an expert on the ArcSDE side, but I have heard that a good approach is to get an unmanaged raster catalog up and working with a file geodatabase and your tif files. Once that's working, then you can convert the whole package to a true ArcSDE raster dataset (that process can take days, but in the end you have a very high-performance image service). There are a lot of tweaks on how this is setup so I recommend piloting a lot with small subsets before you load gigabytes of data into ArcSDE.  This is not a simple point and click deal, there is research, database design, testing, and tuning involved to get what you need. You may have noticed: I moved this thread over to the Imagery and Raster Data forum in the hope that some experts in this area may chime in. ... View more

I currently have over 4000 .tif raster data that have to be loaded into a SDE Raster Catalog in ArcGIS 9.3.1.  I had been manually uploading 1800 in batches using the Raster to Geodatabase (multiple) tools. Have you considered creating a file-based raster catalog instead? If you do this you can access all tifs as one seamless raster, and if you set it up as "unmanaged", you will not have to convert them -- they will be accessed as they are by reference. (You are working in 9.3.1; in 10.x you should use mosaic datasets, which are similar but better.) ArcGIS 9.3 Help: Creating raster catalogs in the geodatabase The Workspace To Raster Catalog tool will batch-load a whole folder of .tif files into your raster catalog. If what you truly want to make a single ArcSDE raster dataset, it is fairly straightforward to convert the entire raster catalog to a geodatabase raster -- a lot easier than trying to individually load thousands of rasters. ... View more

... when I run the zone statistics to table tool, it is ignoring the no data values and not recording them in the output table. Is there a way to get some sort of value for all of the polygon cells I am extracting values to even if the underlying raster value is no data? I think you want to fill in data so you will have a row for each model grid polygon, even if there were no data cells for that polygon, right? If you want to "fill in" missing value codes (say, -9999) for the cells that have no stats results (because there is no data to calculate stats for those cells) your only solution I can think of is to select the polygons with no matching statistic, export those rows to a table, and append those rows to your Zonal Stats As Table output. If you append with the NO_TEST option, only fields that match (same name) will be copied. You could then select those "dummy" rows and populate a missing value code for the stats using the Calculate Field tool. Hope this helps... ... View more

    arcpy.CalculateField_management(CbuffersFL,AvgGrpField,(GrpFieldJoinNew/SelectedCount),"PYTHON") The above calculate expression is not properly formed. The divide symbol must be inside the expression string. (This is the same solution you posted earlier today -- in fact I merged the threads here.) Here's a way to approach building the expression using Python string formatting -- generally far easier to debug than adding strings together the way you've been doing it: SelectedCount=int(arcpy.GetCount_management(CbuffersFL).getOutput(0)) # the name is used to prefix the field name prefix = arcpy.Describe(CbuffersFL).name expr = "!{0}.{1}! / float({2})".format(prefix, TotalGrpField, SelectedCount) arcpy.CalculateField_management(CbuffersFL, AvgGrpField, expr, "PYTHON_9.3") Here's how using the python formatting simplifies your field addition calculation: GrpField1= "Nest_All.GrpSz08" GrpField2= "Nest_All.GrpSz09" GrpField3= "Nest_All.GrpSz10" GrpField4= "Nest_All.GrpSz11" GrpField5= "Nest_All.GrpSz12" fmt = "!{0}! + !{1}! + !{2}! + !{3}! + !{4}! + !{5}!" Grpexpression = fmt.format(GrpField1New, GrpField2New, \                    GrpField3New, GrpField4New, GrpField5New) Python also has a sum function for lists, so you could have done this too: fmt = "sum([!{0}!, !{1}!, !{2}!, !{3}!, !{4}!, !{5}!])" Grpexpression = fmt.format(GrpField1New, GrpField2New, \                    GrpField3New, GrpField4New, GrpField5New) Hope this helps you out. ... View more

Thanks, Dale -- appreciate the guidance. If you do plan to change the default, please recommend that the online help for Calculate Field starts to warn us now! 🙂 ... View more