Latest Contributions by ChrisSnyder

This should theoretically do it: undefinedSr = arcpy.SpatialReference() #Note this DOES NOT make a 'Unknown' SR obj, see below mxd = r"C:\temp\my_mxd.mxd" for df in arcpy.mapping.ListDataFrames(mxd):    df.spatialReference = undefinedSr mxd.save() del mxd   However, I found this is actually a bit more difficult.... The trick is to get a SR object to be of a "Unknown" coordinate system. The only way I could do this was to run the DefineProjection tool, and manually clear out the 'Coordinate System' parameter - which makes its value then default to a magic value called Unknown (note this is NOT a string value of "Unknown", but something else). Once I had a FC defined with an Unknown SR, then: undefinedSr = arcpy.Describe(unknownSrFC).spatialReference mxd = r"C:\temp\my_mxd.mxd" for df in arcpy.mapping.ListDataFrames(mxd):    df.spatialReference = undefinedSr mxd.save() del mxd Which worked... Anyone know a better way to create an Unknown spatial reference object? Tried all these, which do not work: undefinedSr = arcpy.SpatialReference(None) undefinedSr = arcpy.SpatialReference(0) undefinedSr = arcpy.SpatialReference("Unknown") undefinedSr = arcpy.SpatialReference(Unknown) Seems like there should be a EPSG code for Unknown/Undefined, but I can't find it... ... View more

Sometimes the Union tool is confused with the Merge/Append tools... Is your intention to just move all the data into a single featureclass (aka Merge/Append) or to actually overlay the geometry (aka Union)? ... View more

See the tool PointsToLine tool: http://resources.arcgis.com/en/help/main/10.1/index.html#//00170000003s000000 That is an intereseting analysis... Seems like you would need to also "length-weight" the times for the portion of the line that lies within a particular summany grid. Some basic Python scripting knowledge would surely be a big help. ... View more

What if you try to delete the FC(s) before you run all the list functions? ... View more

Hopefully the other tools mentioned in this thread that suffer from the same/simlar issue were also addressed. ... View more

Not sure, but I bet FindIdentical simply rounds the values - maybe with the xy tolerance value (or some derivation of it) of the FC? All I'm really interested in is which shapes are identical to each other after a union operation on buffers. I assume to figure out overlaps? I do this too... I just round the values of the centroid x/y coordinates and the polygon area. If it helps give you ideas: #Flatten this puppy! shatteredFC = fgdbPath + "\\shattered" arcpy.Union_analysis(dissolveFC, shatteredFC, "ALL", "1 FEET", "GAPS"); showGpMessage() singlePartFC = fgdbPath + "\\single_part" arcpy.MultipartToSinglepart_management(shatteredFC, singlePartFC); showGpMessage() searchRows = arcpy.da.SearchCursor(singlePartFC, ["SHAPE@","*"]) polyIdDict = {} polyIdValue = 1 decimalTolerance = 2 for searchRow in searchRows:     shapeFieldValue = searchRow[searchRows.fields.index("SHAPE@")]     xCentroidValue = round(shapeFieldValue.centroid.X, decimalTolerance)     yCentroidValue = round(shapeFieldValue.centroid.Y, decimalTolerance)     areaValue = round(shapeFieldValue.area, decimalTolerance)     axyValue = (xCentroidValue,yCentroidValue,areaValue)     catagoryNameValue = searchRow[searchRows.fields.index("CATEGORY")]     releaseYearValue = searchRow[searchRows.fields.index("RELEASE_YR")]     retentionPctValue = searchRow[searchRows.fields.index("RETENTION_PCNT")]     forestedFlagValue = searchRow[searchRows.fields.index("FORESTED")]     if axyValue not in polyIdDict:         polyIdDict[axyValue] = polyIdValue, [catagoryNameValue], [releaseYearValue],[retentionPctValue],[forestedFlagValue]         polyIdValue = polyIdValue + 1     else:         polyIdDict[axyValue][1].append(catagoryNameValue)         polyIdDict[axyValue][2].append(releaseYearValue)         polyIdDict[axyValue][3].append(retentionPctValue)         polyIdDict[axyValue][4].append(forestedFlagValue) del searchRow, searchRows #Sort the thing the way we want it for axyValue in polyIdDict:     polyIdDict[axyValue][1].sort() #catagory name     polyIdDict[axyValue][2].sort(reverse=True) #release year     polyIdDict[axyValue][3].sort(reverse=True) #retention percent     polyIdDict[axyValue][4].sort() #forested arcpy.AddField_management(singlePartFC, "POLY_ID", "LONG"); showGpMessage()  arcpy.AddField_management(singlePartFC, "LCL_RSN", "TEXT", "", "", "150"); showGpMessage() arcpy.AddField_management(singlePartFC, "RELEASE_YR_MAX", "SHORT"); showGpMessage() arcpy.AddField_management(singlePartFC, "RETENTION_PCNT_MAX", "SHORT"); showGpMessage() arcpy.AddField_management(singlePartFC, "FORESTED_MAX", "TEXT", "", "", "1"); showGpMessage() arcpy.AddField_management(singlePartFC, "LCL_RP_FLG", "SHORT"); showGpMessage() arcpy.AddField_management(singlePartFC, "LCL_UP_FLG", "SHORT"); showGpMessage() arcpy.AddField_management(singlePartFC, "LCL_US_FLG", "SHORT"); showGpMessage() arcpy.AddField_management(singlePartFC, "LCL_WT_FLG", "SHORT"); showGpMessage() updateRows = arcpy.da.UpdateCursor(singlePartFC, ["SHAPE@","*"]) for updateRow in updateRows:     shapeFieldValue = updateRow[updateRows.fields.index("SHAPE@")]     xCentroidValue = round(shapeFieldValue.centroid.X, decimalTolerance)     yCentroidValue = round(shapeFieldValue.centroid.Y, decimalTolerance)     areaValue = round(shapeFieldValue.area, decimalTolerance)     axyValue = (xCentroidValue,yCentroidValue,areaValue)     updateRow[updateRows.fields.index("POLY_ID")] = polyIdDict[axyValue][0]     updateRow[updateRows.fields.index("LCL_RSN")] = ",".join(i for i in sorted(set(polyIdDict[axyValue][1])))     updateRow[updateRows.fields.index("RELEASE_YR_MAX")] = polyIdDict[axyValue][2][0]     updateRow[updateRows.fields.index("RETENTION_PCNT_MAX")] = polyIdDict[axyValue][3][0]     updateRow[updateRows.fields.index("FORESTED_MAX")] = polyIdDict[axyValue][4][0]     if "RIPARIAN_AREA" in polyIdDict[axyValue][1] or "RMZ" in polyIdDict[axyValue][1]:         updateRow[updateRows.fields.index("LCL_RP_FLG")] = 1     if "WETLAND" in polyIdDict[axyValue][1] or "WMZ" in polyIdDict[axyValue][1]:         updateRow[updateRows.fields.index("LCL_WT_FLG")] = 1     if 'SLOPE_STABILITY_ISSUE' in polyIdDict[axyValue][1] or 'SLOPE_STABILITY_POTENTIAL' in polyIdDict[axyValue][1] or 'SLOPE_STABILITY_VERIFIED' in polyIdDict[axyValue][1] or 'UNSTABLE_SLOPES' in polyIdDict[axyValue][1]:         updateRow[updateRows.fields.index("LCL_US_FLG")] = 1     #A bit of a work around just for SPS - untl the new schema is completed...     if 'AREA_REGULATION' in polyIdDict[axyValue][1] and polyIdDict[axyValue][3][0] < 50:         updateRow[updateRows.fields.index("RETENTION_PCNT_MAX")] = 50     updateRows.updateRow(updateRow) del updateRow, updateRows ... View more

Assuming your geometries have some true curves in them, I bet that if you convert your FC to a shapefile, then look at the WKT values, they "should" then be ==. About a year ago, I had been in contact with ESRI about this issue (true curve geometry being slightly off).... didn't go anywhere though... ESRI commited to curve geometry. No plans to have an envr setting to keep the GDB geometry densified (which seems to prevent these minute geometry property differences). ... View more

I feel your pain: http://forums.arcgis.com/threads/49557-True-Curves-True-Evil http://forums.esri.com/Thread.asp?c=93&f=983&t=292699 ... View more

I don't have any experence with teh WKT values, but how different are the values (you mention length)? I have had issues with geometries that include "true curve" features, that should be identical, but in fact have ever so slightly different areas/perimeters/centroid values - I am talking like a difference of 0.00001 map units. But enough to throw my script logic out of whack. ... View more

How about the online documentation (v10.0): http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html ... View more

How about using the Con() function? In v10.0 + raster calculator syntax you have to use the Lookup() function to access fields other than the VALUE field. For example, this expresion will return a value of 1 if the NST field value is >= 50 and the DEM_FLAG field value is 0 (otherwise it returns NoData. arcpy.sa.Con((arcpy.sa.Lookup(nstGrd, "NST") >= 50) & (arcpy.sa.Lookup(nstGrd, "DEM_FLAG") == 0), 1) ... View more

Do you know if you can obtain the results from the SNAP_EDIT, like it snaped x number of features...?   I suspect there isn't a direct way to do this... I would think you would have to inspect the geometry to see what changed. Maybe there is something in the result object though, but I doubt it. You'll always be a 490 to me... ... View more