Import LiDAR data into grasshopper

Hi there,

I have modelled an urban tile, comprising of extruded building footprints and ground elevation contours, both imported shp files in Projected Coordinate system WGS_1984_World_Mercator.
At the same model, I would like to import the trees as point clouds/points, after being classified as high vegetation from LiDAR data (las file), available in the Coordinate system GDA_1994_MGA_Zone_55. The LiDAR data were classified using LiDAR360 software and saved back to las file and txt file with xyz coordinates, classification and RGB information (ASCII I assume). As expected, when I import the txt file in grasshopper, the oint cloud is not places at the right place, along with the buildings and terrain.

Inside the ArcGIS environment, the building polylines, the terrain contours and the las data seem to overlay correctly, however, ArcGIS does the ‘projection on the fly’. In ArcGIS, while I can use the tool ‘Project’ to change the projected coordinate system of a layer to another, it seems I can’t do the same with las files. The only way I came up with to project the las points to WGS_1984_World_Mercator was to covert las to multipoints, and then add a new field with the points’ height. Later, I import the shp file (points) and I move the points to the right height using the information of the height field.

Is there a more appropriate way to project las classified points to another coordinate system, inside grasshopper or ArcGIS (or anywhere else really, like CloudCompare) and then export the data as points or coordinates (ACSII etc)?



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Just for the reference, the tool ‘Extract LAS’ can project the las file to another coordinate system inside ArcGIS Pro. The transformation to xyz coordinates can be done in pretty much any LiDAR data or point cloud software like CloudCompare or LiDAR360.
Problem solved :slight_smile: