[pdal] Downloading USGS LPC data with PDAL

[Andreas Yankopolus]

Connor—

> You can intersect your AOI with the GeoJSON boundaries to determine your overlaps: https://raw.githubusercontent.com/hobu/usgs-lidar/master/boundaries/resources.geojson <https://raw.githubusercontent.com/hobu/usgs-lidar/master/boundaries/resources.geojson>
> 
> This is updated automatically daily here: https://github.com/hobuinc/usgs-lidar/tree/master/boundaries <https://github.com/hobuinc/usgs-lidar/tree/master/boundaries>
This is perfect. It will be a straightforward task to write a Python script that uses GDAL to perform the overlap calculations to determine the relevant collects.


Kirk—

> I could have this wrong, but I think the json file that has the boundaries for the EPT datasets can be found at https://github.com/hobuinc/usgs-lidar/blob/master/boundaries/boundaries.topojson. That would allow you to figure out which datasets are within an AOI. Standing up a service that would let you specify an AOI and then spit back all the points, merging the different collects as it goes, has some inherent problems. It's technically feasible; the issue is that some things shouldn't be mixed. For example, pre and post-event collections for hurricanes.

Point taken on being careful with the merges. I’m using the LPC data to get a rough idea of average building/tree heights for radio propagation calculations, converting the LPC data to surface-height raster files with resolutions between 3m to 30m.

To date I’ve been converting LPC tiles to a raster tiles in parallel, then merging the raster tiles with GDAL as a sequential operation. I’m often processing several hundred square km of data at once, and telling PDAL to load all that data into memory at once doesn’t work out. Maybe there’s a trick I’m missing?

Thanks,

Andreas

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