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16

Given that you have the LIDAR DEM, you should use the streams derived from it. That guarantees perfect registration. The crux of the idea is to estimate mean slopes in terms of the elevations at the ends of the segments. One of the easiest procedures is to "explode" the stream network into its component unbranched arcs. Convert the collection into a ...


12

Commercial: FME Desktop " ability to take a point cloud that has no color information on it, and overlay it into an orthophoto to produce a colorized point cloud" http://blog.safe.com/2012/01/beating-lidar-into-submission-with-fme-2012/ LP360 Add-on to ArcGIS http://www.qcoherent.com/products/index.html LP360 for ArcGIS™ (Basic, Standard and Advanced) ...


11

Your PointsXYZIC is now a numpy array. Which means you can use numpy indexing to filter the data you're interested in. For example you can use an index of booleans to determine which points to grab. #the values we're classifying against unclassified = 1 ground = 2 #create an array of booleans filter_array = np.any( [ PointsXYZIC[:, 4] == ...


8

This sounds like Tom Patterson's work on Resolution Bumping GTOPO 30 in Photoshop. The theory is described well enough to be adaptable to other software, though work needs to be done coming up with the specifics. The basic idea is to generalize (blur) one data set, a lot, to emphasize the general shape and hide specific detail and then blend the hi-res and ...


8

Tips: Note: Your computer has plenty of spec: Develop a full or partial disk cache whenever possible. Disk caches allow data to be pre-rendered for optimum ArcGlobe/ArcScene display performance. Store ArcSDE/ArcScene data sets using the Cube projection This will avoid pyramid resampling and data reprojection for ArcGlobe. ...


8

A common mistake (that I've made too) is to down-sample a raster using the resample tool with bilinear interpolation. See this answer for an explanation why this is not good. A raster can be down-sampled in three steps. The first step might not be required. Reproject the raster to the target extents. Use bilinear interpolation, and keep the output cell ...


8

FUSION/LDV is a powerful and solid open source option developed by the USDA Forest Service to analyze and visualize LiDAR data. General information about FUSION can be found here: Overview of FUSION features: Generates DEMs from point data Produces bare earth surfaces from unfiltered points Displays image data for background reference Subsamples large ...


7

There is no way to get floor heights from a lidar pointcloud. Lidar is captured by bouncing lasers off the groundsurface and measuring the bounced back pulses. Therefore there is no way for the lasers to 'see' through the roof of a building and return a floor height. However, a solution to this may be to classify your las point cloud into ground and non ...


7

Inside a Geodatabase, there are certain ways you can't name a table or Feature Class. Beginning with a number is one of those ways. Validating Table and Field Names in Python: http://resources.arcgis.com/en/help/main/10.1/index.html#//002z00000020000000 Try renaming your table to las_1 or something and see if it works


7

laspy is another good LAS read/write software. It supports working with the data directly in numpy arrays and a number of other nice Pythonic features. It isn't processing software per se, however. PDAL has the ability to use Python as an in-pipeline filtering language, but this isn't a processing engine either. There isn't too much in the Python quiver ...


6

Sounds like you're wanting to do this in batch (don't blame you) As STH said, looks like Global Mapper will indeed do batch conversions. Nice price as well. FME Desktop can do using the RasterDEMGenerator transformer and a bit of linking with reader/writer, but you'll need the Pro version, not available in the ArcGIS Data Interop extension. If free is ...


6

There are a number of places where footprints can come in very handy Public Sector: Taxation: As @Mapperz said, taxation is one area. The percentage of property that is built on is sometimes used as a tax criterion. Planning: Knowing where structures already exist on property can help in the planning process due to applied setbacks and minimum ...


6

(The answer is based on my and others' comments above; haven't really tested it) Store the points as MultiPointZM. The best grid size would probably be dependent on access patterns and you need to do some testing on this. A regular grid with a spatial index should make queries quite fast. If 3d access is important then MultiPointZM could be 3D block ...


5

How to compare two Digital Elevation Models (DEMs) Solution using the software R. #------------------------------------------------------------------------- #Creating a reproducible example library(raster) #simulating raster_1 f = system.file("external/test.grd", package="raster") DEM_1 = raster(f) #simulating raster_2 DEM_2 = DEM_1 # ...


5

I provide a number of sample LiDAR files at http://liblas.org/samples that you can download. These are mostly example data, but many are quite interesting. You can use the las2txt utility that libLAS provides (or Isenburg's las2txt version as well) to convert them to XYZ ascii files. Isenburg's tools also provide a number of fantastic triangulation ...


5

The tool lasgrid.exe (README) from LAStools does a "direct" conversion with gridding (without triangulation) very fast. The tool las2dem.exe (README) from LAStools rasters the points via a temporary TIN. Regards, Martin @lastools


5

Try running the sp_help_spatial_geography_index stored procedure to get details on how your spatial index is being used. You should be able to use something like: declare @ms_at geography = 'POINT (-95.66 30.04)' set @ms_at = @ms_at.STBuffer(1000).STAsText() exec sp_help_spatial_geography_index 'lidar', 'SPATIAL_lidar', 0, @ms_at; Post the results in ...


5

There are several online videos showing how to use Image Analysis with Lidar data with eCognition. Image Classification methods are key to extracting the correct data. http://www.ecognition.com/news/ecognition-tv/ Vegetation (Tree Canopy Extraction) http://www.ecognition.com/news/ecognition-tv/extracting-tree-canopy-lidar Building Extraction ...


5

It all depends on where you draw the line. Regardless, this problem looks like it can be readily addressed using the morphological functions available in Spatial Analyst, especially thresholding (performed with "<" and ">" local operations) and "RegionGroup" to identify and extract components. Although I do not have access to the DEM to illustrate, the ...


5

You can cut a step out of the process by using the Aggregate tool, which avoids having to replicate all those summary value cells, and the Resample.


5

2 points per meter is plenty for what you want to do. I assume the company that is flying the LiDAR is going to develop your solar analysis, digital surface models, etc...? If not, how are you going to do this? What software are you using? Your computer is plenty powerful, but if you are using incorrect workflows/software it can slow down the processing, ...


5

libLAS can indeed be used commercially. So can Martin Isenburg's LASlib, which is LGPL, and speaking as the author of libLAS, faster and more completely supported than libLAS. Both are indeed C++ libraries, however, and there isn't too much in the ASPRS LAS space for native .NET. I'm also the primary author of PDAL, and PDAL can also read ASPRS LAS data, ...


5

Sub-centimeter elevation? No. This article provides a good overview of LiDAR and the associated errors (Range, Position & Orientation). Operationally, when working with LiDAR data we assume a potential 5-10cm vertical and horizontal error. At times it may be much more accurate, but it's not sub-cm.


5

LASTools can perform a ground classification using "lasground" and then can perform some limited feature classification using "lasclassify". The performance and quality of feature classification in point clouds is strongly influenced by the type of landscape collected. Some landscapes just do not lend themselves to acceptable automated results. The best ...


5

Have you worked with Fusion/LTK? It is a free software for LiDAR processing and visualization. I would do this in two steps: Convert the LiDAR xyz'.txt' files to '.las' with ASCIIIMPORT tool. Filter out ground returns* outliers using the '.las' file, with GroundFilter tool. *from you comment under simplexios's answer I'm assuming the LiDAR data are only ...


5

A paid LAStools toolbox has been released for QGIS by Rapidlasso GmbH. Instructions on installing it can be found at: http://rapidlasso.com/2013/09/29/how-to-install-lastools-toolbox-in-qgis/ You can find the pricing information on this page: http://rapidlasso.com/pricing/


5

You can install libLAS: compiling it (Using “XCode” on OS X) installing it with Homebrew (Homebrew Formulas: Liblas) Or you can use GRASS GRASS GIS Wiki: Lidar or Cloud Compare with a new Mac OS X port Mac OS X: CloudCompare


5

This looks like a valid workflow for this task. However, depending on the level of accuracy that you work with, you will miss out on things like pipes under roads allowing for ditches and small creeks to flow past the road. These would probably require some field work to identify though. You don't mention which software you use, but for ArcMap point (6) ...


5

It really depends on what you're going for here. If your goal is to make accurate measurements, you will want the grid spacing to be smaller, around the average point spacing of the dataset. If this is part of a process of creating orthophotos or analyzing watersheds, or any other task which requires a more generalized terrain model, you will want the ...


4

I see "ArcGIS" is a tag, Jakub. Using Spatial Analyst you would simply compute a weighted average of the two hillshades. E.g., the 60-40 mixture could be generated with a calculation like this: (60*[Detailed hillshade] + 40*[Generalized hillshade]) / 100 If you need it, the Gaussian blur can be executed by running a few circular focal means over a ...



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