Latest Contributions by NeilAyres

‎01-16-2014

Are all of your bil files correctly georeferenced and on the WGS84 datum? If so, follow the code template given by Jake above. The WKID for WGS_1984_UTM_Zone_37N is 32637, so, rather than listing the entire text for the projection, I would use the WKID to create a spatial reference object for use in the Project function. Thus : import arcpy from arcpy import env env.workspace = r"Your path to the data here" srOut = arcpy.SpatialReference(32637) for raster in arcpy.ListRasters("*.bil"): arcpy.ProjectRaster_management(raster, raster + "_project.bil", srOut) See the examples here : http://resources.arcgis.com/en/help/main/10.2/#/Project_Raster/00170000007q000000/ Cheers and good luck, Neil

‎01-13-2014

There is a GetCellValue function that can be used in python to query values in a raster, but it is quite slow. And there maybe really fast ways of doing this using numpy arrays. But why not use RasterToPoint, then process the resulting point attribute table. Can't remember if R2P will export all 4 bands or if you would have to do each band separately. If the raster is very large, it will of course give you a very large number of points to process. Cheers and good luck, Neil

‎12-24-2013

If NPP and ZforCDF are rasters on disk, shouldn't they be referenced to Raster objects before all that long calculation? Like : NPP = arcpy.Raster(r"D:\PROGRAMMES\LFP_Source_Rocks\ArcGIS\00_LFP_GLOBAL_MODEL\LFP_GLOBAL_Python\OUTPUT.gdb\NPP") etc

‎12-20-2013

Jon, I think this is a 2 stage process. Make the contours then use 3d analyst / 3d features / Feature to 3d by attribute. The Z value will be "Contour". Then you will have a true polylineZ. Cheers, Neil

‎12-20-2013

Have you tried using print NPPEquation just to see exactly what is being returned by the GetParametersAsText. It should work, but only if NPPEquation is exactly "Min NPP1" Not much, I know but good luck, Neil

‎12-19-2013

The 3d analyst / Functional Surface / Add surface information tool will take your polyline and add info from a surface. One of the options is "Average slope". You can only add a surface statistic for each feature (like minZ, maxZ, slope etc.) If you need finer control you would probably have to dump the line vertices out to points then add the surface information to that. Good luck, Neil

‎12-16-2013

You need to project your data from GCS to a flat projected coordinate system. http://resources.arcgis.com/en/help/main/10.2/index.html#//003r0000000q000000 Your biggest problem here will be to select a suitable PCS for your analysis. This will depend on what you are doing with the data. You may have to consider splitting up the data into continental sized bits and projecting each one separately. Cheers, Neil

‎12-11-2013

James, tested this code : # test sa.sample import sys, os, arcpy from arcpy import env from arcpy.sa import * arcpy.CheckOutExtension("Spatial") InputFGDB = "c:/Data/ESRI-SA/ArcForums/TestData.gdb" env.workspace = InputFGDB RasList = arcpy.ListRasters() print RasList inPnts = "SamplePnts" outTab = "in_memory/sampTbl" Sample(RasList, inPnts, outTab, "NEAREST") env.workspace = "in_memory" tbl = arcpy.ListTables()[0] recs = arcpy.GetCount_management(tbl).getOutput(0) print "Table {} records {}".format(tbl, recs) listFields = arcpy.ListFields(tbl) for f in listFields: print f.name which gave me this.... >>> [u'IP_bi', u'RES_bi'] Table sampTbl records 200 OBJECTID SamplePnts X Y IP_bi RES_bi >>> So no errors on my side. No answer for you, sorry. Cheers, Neil

‎12-10-2013

This succeeds if FGDB is on disk: ws_output = r'\\NetworkPath\GDB\Conc2.gdb' elevrasname = "tabElev" outelevtab = ws_output + "\\" + elevrasname arcpy.sa.Sample(rasters, transect_in, outelevtab) This fails: outelevtab = "in_memory" elevrasname = "tabElev" outelevtab = ws_output + "\\" + elevrasname arcpy.sa.Sample(rasters, transect_in, outelevtab) James, in your second bit of code, outelevtype is being assigned twice and there is no assignment for ws_output. So perhaps that second bit should be... ws_output = "in_memory" elevrasname = "tabElev" outelevtab = ws_output + "\\" + elevrasname arcpy.sa.Sample(rasters, transect_in, outelevtab) I also find it is better to use that os.path.join(var1, var2) construct to piece variables together to make paths. Cheers, Neil

‎12-04-2013

I have also been struggling to get a tile package up to my online account. I have a tpk which is ~50Mb. Yesterday I used the "Share Package" tool to upload it. Left it running for ages, but noticed that the progressor bar would get to about 80%, then it would mysterious start again. No idea if it was doing different parts of the process or it was actually resetting itself. While this was happening my bandwidth was totally chewed up, so it was sending something somewhere. Eventually cancelled it after 3hrs. Any advice? Cheers, Neil

‎12-03-2013

Firstly I would dump shapefiles and get the data into a geodb. A shapefile with 2mill records might be getting close to its max size (the *.dbf part), 1Gb I think, may be wrong. That error message is usually when the geometry part is getting out of kilter with the attribute part, one doesn't match the other and is normally fatal for shapefiles. Cheers, Neil

‎12-02-2013

Thanks Xander. My initial confusion about accessing the RAT table is functions like ListTables reveal no RATs. So its there but its not there sort of thing. But having all the raster parameters available with a Raster object is also quite handy, without having to go through a Describe object. Yes, I see that if the permanent Raster is supplied to the da.SearchCursor, it reads the RAT fine. Just a slight bit of inconsistency revealed here. Cheers, Neil

‎12-01-2013

Last week I answered a query about Null / Not Null counts in a raster. As an aside there I asked about accessing the RAT from a raster. After a bit of searching I have found the solution, its not quite what I expected. Import the modules, navigate to my gdb containing the rasters, create a raster object "Ras1" and validate that it does indeed have a RAT. >>> import sys, os, arcpy >>> from arcpy import env >>> env.workspace = "c:/Data/Python/NumPyArrays/ZimDem.gdb" >>> arcpy.ListRasters() [u'DemFill', u'FlowDir', u'DemFill_hs', u'Ras2', u'Ras3', u'Dem', u'Dem_hs', u'FlowD', u'Ras', u'FlowD_Temp', u'Dem_MaxUpstreamElevation', u'Temp', u'Dem_DD', u'CreateConsta1', u'XMapFinal', u'YMapFinal'] >>> arcpy.ListTables() [] >>> >>> Ras1 = arcpy.Raster("FlowD") >>> Ras1.hasRAT True Try to use da.SearchCursor to list the RAT. for r in arcpy.da.SearchCursor(Ras1, ["VALUE", "COUNT"]): print r[0], r[1] Traceback (most recent call last): File "<pyshell#11>", line 1, in <module> for r in arcpy.da.SearchCursor(Ras1, ["VALUE", "COUNT"]): RuntimeError: 'in_table' is not a table or a featureclass So the da.SearchCursor method, errors out because Ras1 is a raster object, not a table. Fair enough you might think. However, then try the "old" SearchCursor... rows = arcpy.SearchCursor(Ras1, "", "", "VALUE; COUNT") >>> for r in rows: v = r.getValue("VALUE") c = r.getValue("COUNT") print v, c 2 4254.0 4 4093.0 8 1572.0 16 3615.0 32 4112.0 64 9199.0 128 6344.0 >>> So the old SearchCursor doesn't mind that the input is a raster object, and lists the Value; Count list no probs... How odd is that? Cheers, Neil

‎11-29-2013

Wouldn't SA tools, Local, Cell Statistics do what you want to do. Cheers, N

‎11-28-2013

Chenay, wanted to reply earlier but the connection went down with the storms. Try this bit of python : import sys, os, arcpy from arcpy import env from arcpy.sa import * if arcpy.CheckExtension("Spatial"): arcpy.CheckOutExtension("Spatial") else: print "No SA licence" exit HomeDir = "c:/Path to directory here/" fgdb = "Name of your fgdb.gdb" InData = os.path.join(HomeDir, fgdb) env.workspace = InData env.overwriteOutput = True ListRast = arcpy.ListRasters() for r in ListRast: print "Processing", r Ras = arcpy.Raster(r) NullRas = IsNull(Ras) NCol = NullRas.width NRow = NullRas.height NCell = NCol * NRow Mean = NullRas.mean NNull = Mean * NCell print "{} % Null {}".format(r, NNull / NCell * 100) Works for me... As a matter of interest, I tried to find out how to access a raster attribute table in python, but didn't come up with anything. Could Steve Lynch or Xander or some other genius enlighten us. Cheers, Neil

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My Ideas

Latest Contributions by NeilAyres

Re: Projecting multiple images from one coordinate system to another,

Re: recording pixel value with Python script in ArcGIS 10.x

Re: Unsupported operand error

Re: Contour Lines Are Not Z-Enabled

Re: Spaces in String Variable

Re: Extract elevation value from both ends of polyline?

Re: Converting DEM cell size from degrees to meters

Re: arcpy.sa.Sample() Spatial Analyst "Sample" method

Re: arcpy.sa.Sample() Spatial Analyst "Sample" method

Re: Publishing tiles either works in 15 min or freezes

Re: error: Number of shapes does not match the number of table records

Re: Reading a Raster Attribute table

Reading a Raster Attribute table

Re: Calculate percentage of NODATA pixels in a scene

Re: Calculate percentage of NODATA pixels in a scene

Re: How to create contour lines/or raster from poi...

Re: Contour Lines Are Not Z-Enabled

Re: Finding maximum value between multiple rasters

Re: Converting DEM cell size from degrees to meter...

Re: Make Arcpy use Esri Feature Service

Coordinate Reference Systems