From time to time, we use LiDAR data for modelling in ArcGIS. Previously, we would be supplied either an .xyz or .ascii of the data, but more recently, we are also being provided .las files in addition to the .xyz and ascii's.
I was reading this article which states "Having lidar in LAS format may be obvious to the initiated but not to those new to using lidar data" and "It's binary, efficient, widely supported, and the format ArcGIS works best with". I am one of those people who fall into the category of new to using .las formats.
Normally with the .xyz and ascii, I would use Global Mapper to convert them to a raster grid (for use within modelling) and it appears that I would also need to convert the .las file as well (being a point cloud). I guess the question that I am asking is:
Are there any benefits of using a .las compared to an .xyz or ascii if I still need to convert them to another raster format (GRID or .img)?
Answer
ArcGis has a new LiDAR dataset at 10.1 which will allow you to view your LiDAR data directly and also see more information than what's in a raster... for example you can add to ArcMap and then filter down the display to just tree classes, or just first returns!
LiDAR data contains much more than just elevation, there's intensity that is stored by default (which can assist where no orthos are available) and they should be classified to ground/non-ground at the very basic; full classification is the most useful (ground, low/medium/high vegetation, buildings, water, bridges, powerlines...) for filtering depending on what you're looking for.
Should you have access to a 3d analyst licence you can convert your LAS dataset to a raster with any cell size you desire or you can view with facets...
IMO I think that it is very wise to get both a raster (use now and with existing processes) and LiDAR data (develop new processes) in a delivery.
No comments:
Post a Comment