[gpl_list] GPL Review of the Draft LiDAR Standard

[Brady Callahan]

I won't be able to make the GPL meeting today but had a couple comments on the draft LiDAR standard that I wanted to share with the group:

-There are existing FIT standards for both elevation point data (Oregon Elevation Data Standard) and geodetic point data (Geodetic Control Data Content Standard) so what is the necessity of a third standard for points that are 3D in nature? Could refinement of one of the existing standards accomplish the same thing (ie add 'Mass Points' to the elevation standard and include additional optional elements like file format)

-If this standard moves forward it should be expressly limited to airborne LiDAR data. LiDAR technology encompasses multiple platforms (terrestrial, mobile, airborne) and these may have different needs than are covered by this proposed standard. As an example, the ASTM has recently adopted standard E2761 (aka E57 Format) which is for 3D imaging data from multiple technologies including laser scanners, 3D range cameras, and laser radar. Lecia, Optech and Riegl are examples of LiDAR manufacturers that have declared support for this standard. 

-The draft standard does not include a component for the LAS Header Block which is required for a LAS file to be correctly interpreted. For example, the draft standard states that the format for the X,Y,Z fields should be in the format 'Long', this does match the ASPRS standard. However, without the LAS Header Block fields X scale factor, Y scale factor, Z scale factor, the LAS point data (XYZ) can be misinterpreted because it has no decimal scale. 


Sorry I can't make it to discuss this in person...




Brady Callahan, GISP
GIS Program Leader
Oregon Parks & Recreation
725 Summer St NE, Ste C
Salem, OR 97301
brady.callahan at state.or.us

ph. 503-986-0783
fax. 503-986-0792