1 / 14

Using free and/or open source tools to build workflows to manipulate and process LiDAR data

Using free and/or open source tools to build workflows to manipulate and process LiDAR data. Christopher Crosby. Point cloud filtering (classification). Software options for point cloud filtering:. ALDPAT - http://mitigation.fiu.edu/lidartool.html Open source option for full LiDAR workflow:

ceri
Download Presentation

Using free and/or open source tools to build workflows to manipulate and process LiDAR data

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Using free and/or open source tools to build workflows to manipulate and process LiDAR data Christopher Crosby

  2. Point cloud filtering (classification)

  3. Software options for point cloud filtering: • ALDPAT - http://mitigation.fiu.edu/lidartool.html • Open source option for full LiDAR workflow: • Task 1. Split Tape Files into Strips • Task 2. Separate First and Last Return Measurements from a 9 Column Strip File • Task 3. Convert ellipsoid to orthometric heights • Task 4. Estimate strip boundary • Task 5. Merge Boundary Files • Task 6. Create Shape File • Task 7. Tile Strips • Task 8. Filter LIDAR Points • Task 9. Gridding Tiles • Task 10. Convert Surfer Grids to ArcGIS Grids • Miscellaneous Tasks • Very linear – output of one task is input for following task

  4. ALDPAT filtering algorithms • Elevation Threshold with Expand Window (ETEW) • Progressive Morphology (PM) • 2D Morphological Filters (Square or Circle Window • Maximum Local Slope (MLS) • Iterative Polynomial Fitting (IPF) • Polynomial Two-Surface Filter • Adaptive TIN (ATIN) • Refer to users guide for description and parameters for each

  5. Software options for point cloud filtering: ArcGIS 3rd Party Extensions: • Qcoherent LP360 - http://www.qcoherent.com/ • VLS LiDAR Analyst - http://www.featureanalyst.com/lidar_analyst.htm • ~ $1k / seat (academic) Industrial Solution: • TerraSolid Software suite - http://www.terrasolid.fi/en/products/4 • $10k - 30k depending upon bundle

  6. Game plan • Convert LAS point data to ASCII - LASTools • Grid ASCII points – Points2Grid • Experiment with search radius and gridding parameters • Visualize results – ArcGIS or Global Mapper • Grid file format conversions and projection - GDAL

  7. Tools: • LasTools (point cloud format conversions) • GEON Points2Grid (DEM generation) • GDAL w/ discussion of EPSG (Raster data conversion and projection) * ALDPAT (point cloud filtering) – time and complexity doesn’t permit full discussion

  8. MS-DOS Commands… • Run > “cmd” to get command line window Basic Navigation: • cddirectory - go into directory • cd .. - up a directory • cd ../.. – up two directories • dir to list contents of a directory • helpcommand - lists flags and usage • exit - … • TAB – auto complete

  9. LAStools • http://www.cs.unc.edu/~isenburg/lastools/ • Martin Isenburg, Jonathan Shewchuk - UNC • “converting, viewing, and compressing LIDAR data in LAS format” • MS-DOS command line tools

  10. GEON Points2Grid • Desktop application to generate DEMs and shot density plots from LiDAR point cloud data. • Same algorithm as available in the GEON LiDAR Workflow system online • Algorithm by Han Kim (UCSD) • Windows implementation by Newton Alex (ASU)

  11. http://lidar.asu.edu/points2grid.html

  12. GDAL - Geospatial Data Abstraction Library • “is a translator library for raster geospatial data formats that is released under an X/MIT style Open Source license by the Open Source Geospatial Foundation” • http://www.gdal.org/ • Very powerful tool for raster file conversions and projection. • Available for Linux, Mac, Windows • Recommend installing full FWTools package which includes GDAL: http://fwtools.maptools.org/ • Open Source GIS Binary Kit for Windows and Linux

  13. EPSG • Numeric codes that refer to a specific coordinate system. Used by software such as GDAL to define projection. • http://spatialreference.org/

  14. http://lidar.asu.edu/LViz.html

More Related