Tiling LiDAR Data

  1. Jarlath O’Neil-Dunne noted that he thinks tiled LiDAR data should include an overlap.
  2. This would allow 32-bit software to mosaic the tiles and eliminate edge effects.
  3. Applied Imagery’s 64 bit version of QT Modeler is an alternative.

An early supporter of the this blog, Jarlath O’Neil-Dunne made a very important comment about the need for overlapping LiDAR data tiles that I wanted to be sure everyone was aware of. As he says he is not actually involved in the procurement process, but if he were his recommendation is that the spec require that the tiles overlap. His reason for this is to eliminate edge effects when converting from LiDAR point data to raster, such as a DTM surface model.

His comment was in reference to the new ASPRS Procurement Guideline post, but he pointed out that his concern is with a USGS spec that he is aware of that prohibits overlapping tiles. Perhaps someone at the USGS can respond to this.

Jarlath points out that mosaicking LAS tiles is not feasible in a 32 bit software environment, but notes that the folks at Applied Imagery have created a 64 bit version of QT Modeler that does allow large data sets to be processed as a single surface. I continue to hear very positive comments from users of this software.

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2 Responses to Tiling LiDAR Data

  1. STH says:

    So what do you do if you need to work with large amount of LAS-files and convert them to a suitable format for for instance orthorectification? If you split an area in 2 smaller pieces and create DEM files from them – then there will be trouble – even in the overlapping areas…

    Do you have a link to the USGS guidelines?

  2. Sorry that I don’t have a link to the USGS guidelines as they were in draft format. I do believe that reasonable sized overlapping LAS tiles would solve the LAS to raster conversion issues that plague so many end users who only have access to software packages like ArcGIS. Once one has overlapping raster tiles, mosaicking and clipping become much easier.

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