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I'm a big fan of raster datasets in a File GDB, and have had no problems so far with them using the basic Arc10.x Hydrology tools. However, I have seen recommendations in tutorials, etc. for ArcHydro that GRIDs are a better raster format to use. As I upgrade to ArcHydro and it's full geodatabase schema so that I can interface with advanced modeling tools in HEC-RAS & HEC_HMS, is there really any reason for me to go back to using GRIDs?
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11-07-2013
08:17 AM
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Are there any issues with these updates in ArcGIS 10.2?
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11-07-2013
08:00 AM
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Louis, To answer your original question, the ABOVE option measure the volume of subsurface earth between your reference elevation and the subject surface model above; the BELOW option measure the volume of air or water between your reference elevation and the surface below. To use the Surface Volume tool rather than the Polygon Volume tool, you need to use the BELOW option, and make sure that the only part of the surface below your reference plan is inside the lake... in other words there can't be areas of sub-water level elevation outside the lake in your overall surface. -Cam
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02-17-2013
11:17 AM
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Louis, Try using the Polygon Volume tool with the BELOW option to compute the water volume in your lake at various elevations. Create your shoreline polygons for the various elevations by creating contours, then convert selected closed contours to polygons. The tool will add volume and surface area attributes to your lake elevation polygons. -Cam
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02-17-2013
11:04 AM
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This issue is resolved by splitting up the large polygons along the LAS tile boundaries using the Identity tool with the tile boundary index file, so that no polygon spans multiple LAS tiles. What is not resolved is the need in this tool for a LAS Dataset environment setting that allows the tool to process a subset of the point cloud based on existing class value. The problem is caused when the need is to reclassify only ground-classed points to water based on water polygons in a all-points LAS tile, while leaving overhanging riparian trees classed as the correct "unassigned" rather than the uncorrect "water"
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11-19-2012
01:24 PM
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I may be wrong, but don't know of way within ArcGIS to pull class codes into a multi-point from an ASCII file. You can probably do it in a stand-alone python program using the liblas library of python LAS processing tools, to create LAS files with class code, then pull them into multi-points using the 3D Analyst LAS-to-Multipoint GP Tool http://www.liblas.org/tutorial/python.html
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11-19-2012
09:51 AM
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I have multiple-year Lidar coverage of a riverine system consisting of about 1.5 billion points in about 100 (quarter quad) LAS tiles for each year. I also have stereophotogrammetrically-derived water polygons made from lidar intensity image derivatives for each year. Some of the water polygons are for the river itself and span many of the LAS tiles. I want to reclassify the points falling within water polygons to class "9" in all LAS tiles. I did this by running the "Set LAS Class Code Using Features" geoprocessing tool on a LAS dataset created for the entire directory for a particular year. I computed statistics for the LAS dataset before running the tool on it, and checked the "update statistics" box. I'm running Win7-64, dual Xeon quads, 12GB RAM. Arc10.1 SP1. ARc10.1SP1-64bit background processing. I started the tool running at noon yesterday, and I can tell by checking file date modified in WinExplorer that only about half of the files have been processed by 10 hours later. So what's my best strategy for breaking up the work to run more efficiently? I can cut up the polygons on the tile seamlines. Or I could create a series of LAS datasets for sub-sets of LAS tiles and run the tool on those. I haven't test the tool on a LASd containing only 1 or 2 tiles yet. Why does it run so slow? Windows Resource Monitor indicates that CPUs are running at 6%, 6 GB of memory are free, and the disk activity is minimal. I do notice that the disk is going to pagefile.sys pretty frequently, which seems odd given the free RAM available.
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11-19-2012
09:01 AM
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import os,sys,string import arcpy from arcpy.sa import * # this throws an error >>> outraster1 = Raster('DEM2_Sept09') - Raster(1) Runtime error <type 'exceptions.RuntimeError'>: HRESULT(E_FAIL): Unspecified error # this works >>> outraster1 = Raster('DEM2_Sept09') - 1 #this crashes ArcMap >>> outraster1 = Raster(1)
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12-03-2009
12:25 PM
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In browsing the help system I've picked out some of the improved Lidar data handling and processing capabilites, but would REALLY appreciate a concise review of the updates relevant to Lidar data handling in Terrains and multi-points, and point cloud analysis options using python. For example, has access to and handling of LAS attributes like elevation, intensity and return no. in the multi-point data type been improved?
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11-11-2009
01:22 PM
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