Latest Contributions by DuncanHornby

What you are describing is sub-types which is closely linked to domains. Have a look at this walk through, it will guide you through the process. Duncan ... View more

The reason why your equation is failing is that you are using the syntax that grass uses. dem[4,0] means nothing in ArcMap and is an invalid syntax. Reading the web page you linked to it seems that this syntax is all to do with calculating some off-set. I'm not sure if this is a red herring as my raster processing skills is not as good as my vector skills but I know you can shift a grid using the Shift tool. Or maybe someone can suggest some whizzy way of using focal stats? Duncan ... View more

What was your solution? It would be good if you share it with the community... I finally find a solution to my problem. Thanks to all ... View more

Aniket, Why don't you call the existing geo-processing tool Multiple Ring Buffer (Analysis)? There are many examples of how to call a geo-processing tool in Help and on this forum. In ArcObjects consider using the IGeoProcessor interface. Duncan ... View more

The info directory is an important part of an ESRI raster, you will not be able to prevent its generation. With regards to #2 just had an idea, if several processes connecting to the same data is the problem why not duplicate that data but with different names? It looks like you are attempting to use 4 cores so have 4 flow direction grids? Just an idea? ... View more

Mark, Having created a field of type double, you right click on field header run field calculator and complete as shown below. [ATTACH=CONFIG]31854[/ATTACH] Duncan ... View more

Rickey, The VBA code shows you how to extract the display expression for every feature in the layer and prints it to debug window. You can easily adapt this to c# Public Sub PrintDisplayExpressions()     ' Get layer, assumed first in TOC and has a display expression set     Dim pMXD As IMxDocument     Set pMXD = ThisDocument     Dim pMap As IMap     Set pMap = pMXD.FocusMap     Dim pLayer As ILayer     Set pLayer = pMap.Layer(0)     Dim pFeaturelayer As IFeatureLayer     Set pFeaturelayer = pLayer     Dim pDisplayString As IDisplayString     Set pDisplayString = pFeaturelayer         ' Print display string     Dim pFeatureCursor As IFeatureCursor     Set pFeatureCursor = pFeaturelayer.Search(Nothing, True)     Dim pFeature As IFeature     Set pFeature = pFeatureCursor.NextFeature     Do While Not pFeature Is Nothing         Debug.Print pDisplayString.FindDisplayString(pFeature)         Set pFeature = pFeatureCursor.NextFeature     Loop End Sub Duncan ... View more

This sounds like a precision issue. Although you have supplied a sample of your data as Shapefiles is this in fact the storage format you are using? Are you actually using a geodatabase and the XY resolution of the datasets are different? If they are Shapefiles try importing them into a geodatabase with a default XY resolution, then try your code? Duncan ... View more

Mark, You can compute the straight line distance of any polyline with the following python field calculate. First create a field of type double then run a calculate with the python expression getSLDist(!shape!) and the pre-logic script code is: import arcpy def getSLDist(geom):   # Get the end points of the polyline   fp = geom.firstPoint   tp = geom.lastPoint   # Create an Array object and add points to it   array = arcpy.Array()   array.add(fp)   array.add(tp)   # Create a polyline from array, as it only has 2 points in it   # it must be a straight line, then return its length   line = arcpy.Polyline(array)   dist = line.length   return dist Duncan ... View more

Robert, Your error message refers to CopyRaster tool. If you read the Help page Loading raster data into a raster catalog it talks about accessing the raster catalog from ArcCatalog or using the Raster to GeoDatabase tool to load rasters into a raster catalog. Duncan ... View more

Just a comment, how are you running this script? I have never been able to get multiprocessing to work in pyscripter (my IDE of choice). A collegue of mine did use multiprocessing successfully but ran it in IDLE. ... View more

I spoofed up some raster data, mask was an ESRI grid and the false grid was an img format. I filled in the SetNull tool and it worked for me. The only difference I can tell is the expression I used: "VALUE" is null In your question you said you are using: "VALUE IS NULL" Note where the quotes are. Duncan ... View more

Tony, One comment I can make is that you start with the new faster da.cursor then swap back to the slower old style cursor after the ####... line I would recommend as a first stab at improving the speed to change your cursor types. Duncan ... View more

Mark, Have you considered the Linear Direction Mean tool? You can wrap this up in a very simple model. May not be the most speedy way of doing this but will generate a direction line for every segment. See the model below, knocked this up in 2 minutes... You could run this on a subset of your data if you select some lines. Duncan [ATTACH=CONFIG]31729[/ATTACH] ... View more

Philip, What size are your pixels with respect to your zonal data? Are you trying to compare for example a 1Km grid with a polygon that are a few hundred meters wide? I'm guessing some sort of re-sampling error is occurring. Ideally you want to ensure that your zonal data has the same cell size as your raster. May be you should create a raster version of this first and make sure its correct. You'll also want to ensure the snap to raster environment setting has been set. Duncan ... View more