The basic steps of patching or filling a data holiday (hole) in LAS data using LP360 are:
- Draw a polygon (referred to as the “patch” polygon) over the area of the original LAS data that needs to be replaced. Allow a bit of overlap into the good data. You can use the Draw Shape Feature PCT to create the polygon.
- Use the “Classify by Feature” PCT to mark all points within the patch polygon as “Withheld.”
- Load the LAS patch data into a separate TOC layer (do this by ensuring that the “append to compatible layers” option is turned off on the File Load dialog).
- Set the Active LAS Layer to the Patch LAS layer
- Set all points in the Patch to Withheld (setting the Withheld Flag on the points) using either the Classify by Feature PCT or the Basic Filter PCT.
- Use Classify by Feature to reset (clear) all of the Withheld points of the patch LAS that are within the patch polygon
- Remove the Patch LAS by right clicking in the TOC and specifying Remove.
- Reload the Patch LAS but this time ensure that the “Add to Compatible Layers” option is checked. The patch will be loading into the project LAS layer.
- Test for issues at the seam lines such as vertical shifts. Note that you will see higher density around the hole unless you filter by the Withheld flag since the data are being duplicated in this area.
- Export the LAS layer to a new set of cookie cut LAS files with the source filter set to exclude Withheld points.
- Replace the original LAS data with this new merged data set.
