topic Re: LAS to Raster conversion in Python Questions

LAS to Raster conversion

PhilipMuggeridge — Tue, 25 Mar 2014 13:04:28 GMT

Hi,

I'm having a problem setting the interpolation type in the arcpy.LasDatasetToRaster_conversion python code...I wish to use:

Triangulation, LINEAR, NO_THINNING as the options...

however there appears to be no choice when hovering over interpolation type in the python window and I receive the runtime error "Cannot set input into parameter interpolation_type when using 'TRIANGULATION LINEAR WINDOW_SIZE 10' as described in the ArcGIS 10.1 help guide: http://resources.arcgis.com/en/help/main/10.1/index.html#//001200000052000000

The guide talks about arcpy.LasDatasetToRaster_3d in the python window (this doesn't appear to exist...I have checkout out 3D analyst) and arcpy.conversion.LasDatasetToRaster for the standalone python script brings the same runtime error...

Is this a known ESRI bug or am I doing something wrong??? Any help would be much appreciated,

Thanks

Phil

Re: LAS to Raster conversion

JoshuaChisholm — Tue, 25 Mar 2014 13:29:33 GMT

Hello Phil,

Could you please post the exact line you are inputting into the python window (and stand alone script)?

I think you might be inputting the parameters in the wrong way (this tool has an abnormal way of taking inputs).
Would this work?

arcpy.LasDatasetToRaster_3d(inputLASFile, outputRasterFile, 'ELEVATION', 'TRIANGULATION LINEAR NONE')

Re: LAS to Raster conversion

PhilipMuggeridge — Tue, 25 Mar 2014 13:42:21 GMT

Hi,

Thanks for the speedy reply,

In the python window I've just used your comments and set up the following

import arcpy
from arcpy import env
env.workspace = "CURRENT"
arcpy.CheckOutExtension('3D')
inputLASFile = "LAS.lasd"
outputRasterFile = "Raster"
arcpy.LasDatasetToRaster_3d(inputLASFile, outputRasterFile, 'ELEVATION', 'TRIANGULATION LINEAR NONE')

I receive the same error AttributeError: 'module' object has no attribute 'LasDatasetToRaster_3d' as previous

I'm running Standard (ArcEditor) license with 3D analyst switched on

Re: LAS to Raster conversion

JoshuaChisholm — Tue, 25 Mar 2014 14:40:05 GMT

Hello Phil,

I'm confused too...
Try out: arcpy.LasDatasetToRaster_conversion instead of arcpy.LasDatasetToRaster_3d.

Please let me know if that works.

Re: LAS to Raster conversion

PhilipMuggeridge — Tue, 25 Mar 2014 14:47:24 GMT

Hi,

yep so when changing to:

import arcpy
from arcpy import env
env.workspace = "CURRENT"
arcpy.CheckInExtension('3D')
inputLASFile = "LAS.lasd"
outputRasterFile = "Raster"
arcpy.LasDatasetToRaster_conversion(inputLASFile, outputRasterFile, 'ELEVATION', 'TRIANGULATION LINEAR NONE')

I get the error msg:

Runtime error Traceback (most recent call last): File "<string>", line 7, in <module> File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\conversion.py", line 2329, in LasDatasetToRaster raise e ExecuteError: ERROR 000622: Failed to execute (LAS Dataset to Raster). Parameters are not valid. ERROR 000628: Cannot set input into parameter interpolation_type.

I had been using "" instead of 'TRIANGULATION LINEAR NONE' however this is causing an issue in generating a 1m raster where the point spacing and z difference between nearest point in the LAS dataset on undulating ground (coastal areas in particular) causes 'striping' artefacts. Using triangulation will remove this problem and works through the ArcToolbox Las to Raster conversion manual method

Thanks

Phil

Re: LAS to Raster conversion

JoshuaChisholm — Tue, 25 Mar 2014 16:04:12 GMT

I ran the tool manually (with desired settings) and it worked. Then I went to Geoprocessing > Results right-clicked on the tool that just finished running and selected "Copy as Python Snippet". I pasted the code into both the python window and a stand alone script. It worked in both cases.
This is the code that is working for me:

arcpy.LasDatasetToRaster_conversion(inputLASFile,outputRasterFile,"ELEVATION","#","FLOAT","CELLSIZE","10","1")

Let me know if it works for you too Phil!

Re: LAS to Raster conversion

PhilipMuggeridge — Tue, 25 Mar 2014 16:56:37 GMT

Hi,

so I ran it back through using the code: arcpy.LasDatasetToRaster_conversion(inputLASFile,outputRasterFile,"ELEVATION","#","FLOAT","CELLSIZE","1","1")

It outputs a raster however I don't believe it uses the triangulation method I require as comparing results from the python window run with that of the manual method in ArcToolBox (with Triangulation, LINEAR set) the z values on slopes are >10cm different in places from cell to cell....once a hillshade is generated they look very different....we have a previous process in ArcView3.3 that we are trying to re-create and update for Arc10 and it's this output I'm comparing against.

so the issue appears to be why "#" isn't being read as 'triangulation' and I'm currently stumped as to how to input this through python?

Thanks for all your help so far, hopefully we can solve this somehow 🙂

Phil

Re: LAS to Raster conversion

JoshuaChisholm — Tue, 25 Mar 2014 18:23:19 GMT

Good catch Phil.

The rasters are different on my machine too. I've tried poking around in the source code a bit, but with no success. I'm thinking this might be an ESRI issue (as you originally mentioned), perhaps a bug, or at the least a need for improved documentation. So far I've had the following issues:

In the documentation the function is called LasDatasetToRaster_conversion, but the Code Samples use LasDatasetToRaster_3d and LasDatasetToRaster.

The Code Sample (Example 1) doesn't work (or at least not for me).

The Parameter interpolation_type does not seem to work as indicated.

The results from the python code snippet does not produce the same results at the tool it was copied from.

Re: LAS to Raster conversion

PhilipMuggeridge — Tue, 25 Mar 2014 19:27:44 GMT

Hi

Yes I agree I'm seeing those issues, I built the tool in model builder then exported as a python script and had the same issue as the python code snippet. I think It's probably worth forwarding to ESRI for further investigation as we may have come to a dead end? Thanks for all your help, if you have any further thoughts please let me know

Phil

Re: LAS to Raster conversion

JakeSkinner — Thu, 27 Mar 2014 11:09:44 GMT

You may be encountering the following bug, NIM092807.

Re: LAS to Raster conversion

PhilipMuggeridge — Thu, 27 Mar 2014 12:08:21 GMT

Hi,

I tried following the bug support: NIM-092807

I change the interpolation type to "TRIANGULATION NO_THINNING MAXIMUM 1"

Input code: arcpy.conversion.LasDatasetToRaster("test", "test2", "ELEVATION", "TRIANGULATION NO_THINNING MAXIMUM 1", "FLOAT", "CELLSIZE", "1", "1")

I received the same runtime error as previous: Runtime error Traceback (most recent call last): File "<string>", line 1, in <module> File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\conversion.py", line 2329, in LasDatasetToRaster raise e ExecuteError: ERROR 000622: Failed to execute (LAS Dataset to Raster). Parameters are not valid. ERROR 000628: Cannot set input into parameter interpolation_type.

Thanks

Phil

Re: LAS to Raster conversion

JakeSkinner — Thu, 27 Mar 2014 12:28:50 GMT

I would recommend contacting Tech Support. This may be a bug. Tech Support will be able to log it if it is and find a possible workaround.

Re: LAS to Raster conversion

LukeSturtevant — Mon, 15 Dec 2014 12:20:34 GMT

I have been in contact with Christine Dartiguenave from ESRI and she was able to figure out the correct syntax for this tool in python. This has been tested in ArcMap 10.2.2 and is integrated into a tool I have to convert multiple raw LAS files into multiple DEM tiles or one large mosaicked DEM. Of course the inputs and outputs and cellsize must be specified. The tool I have works best when the input LASD is generated using the MakeLasDatasetLayer_management to filter a class code such as 2 for Bare earth. Hope this helps.

arcpy.LasDatasetToRaster_conversion(inputLasd, outputRaster,"ELEVATION","TRIANGULATION NATURAL_NEIGHBOR NO_THINNING MAXIMUM 0","FLOAT","CELLSIZE",cellSize,"1")

Re: LAS to Raster conversion

MartinMachala — Thu, 17 Sep 2015 13:10:33 GMT

Yes, it seems it is really a kind of bug and I am surprised, that nobody from ESRI did correct it so far. In all the help materials and all the script examples they still keep purely wrong information. As I tested the tool (using ArcGis 10.2 and Python 2.7) I found out, that the problem in utilizing this tool via script is in the amount of input items in the {interpolation_type} field. Even when you want a type of interpolation which is using no point thinning (which should really be stated as "NO_THINNING" instead of "NONE" as they advice in the tool help), you must input the items such as Point Selection Method and Resolution. Even though those items are not applied in the calculation, without filling them the tool is not running at all.

I have tested several options and I can say, that in my case are working all the settings using Binning, e.g.:

arcpy.LasDatasetToRaster_conversion(lasd, output, "ELEVATION", "BINNING IDW LINEAR", "FLOAT", "CELLSIZE", "1", "1")

and also settings using Triangulation such as:

arcpy.LasDatasetToRaster_conversion(lasd, output, "ELEVATION", "TRIANGULATION LINEAR NO_THINNING MAXIMUM 0", "FLOAT", "CELLSIZE", "1", "1")

arcpy.LasDatasetToRaster_conversion(lasd, output, "ELEVATION", "TRIANGULATION NATURAL_NEIGHBOR WINDOW_SIZE MAXIMUM 0", "FLOAT", "CELLSIZE", "1", "1") etc.

It seems that I can use any number instead of the "0" for Resolution and the result is always the same. Another strange thing is, that the result is not equal to the same settings with "0" when the tool is running in ArcGIS, but is equal to the result, which the tool in ArcGIS outputs with the default Resolution value calculated uniquely for each dataset (e.g. 0,153884). I did not find out how can I influence the thinning resolution settings at all..

I hope this helps, and others who will get stuck at this bug as I did will not need to test all the options again..

Re: LAS to Raster conversion

Samy_BoumaNgock — Tue, 15 Jan 2019 18:50:04 GMT

Hi community,

Similar problem with arcpy.LasDatasetToTin_3d where the results differ from manual (left) to python (right) settings.

My manual parameters:

which should equate these in python, based on the somewhat unclear documentation:

thintype = 'WINDOW_SIZE'
thinmethod = 'MAX'
thinvalue = '1'
maxnodes = '20000000'
zfactor = '1'

arcpy.LasDatasetToTin_3d(inlasd, outtin, thintype, thinmethod, thinvalue, maxnodes, zfactor)

Have those issues/bugs been resolved or am I also doing something wrong?

Thanks.