Clipping data with polygons¶
- Purpose:
Subset data with a polygon
Assign attribute data
Use PDAL pipeline
Clipping (Autzen)¶

Clipping (setup)¶
Polygons as GeoJSON
Data in two coordinate system
First use of PDAL Pipeline
Clipping (polygon)¶

Clipping (reproject)¶
GeoJSON in Geographic
LiDAR in State Plane
Use OGR VRT
Clipping (vrt)¶
1 2 3 4 5 6 7 8 9 10 | <OGRVRTDataSource>
<OGRVRTWarpedLayer>
<OGRVRTLayer name="OGRGeoJSON">
<SrcDataSource>./exercises/analysis/clipping/attributes.json</SrcDataSource>
<SrcLayer>attributes</SrcLayer>
<LayerSRS>EPSG:4326</LayerSRS>
</OGRVRTLayer>
<TargetSRS>+proj=lcc +lat_1=43 +lat_2=45.5 +lat_0=41.75 +lon_0=-120.5 +x_0=399999.9999999999 +y_0=0 +ellps=GRS80 +units=ft +no_defs</TargetSRS>
</OGRVRTWarpedLayer>
</OGRVRTDataSource>
|
Clipping (pipeline)¶
translate
not expressive enoughComplex operations (merge, filter, write)
Repeatable operations with substitution
Clipping (pipeline)¶
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | {
"pipeline": [
"./exercises/analysis/clipping/autzen.laz",
{
"column": "CLS",
"datasource": "./exercises/analysis/clipping/attributes.vrt",
"dimension": "Classification",
"layer": "OGRGeoJSON",
"type": "filters.overlay"
},
{
"limits": "Classification[6:6]",
"type": "filters.range"
},
"./exercises/analysis/clipping/stadium.las"
]
}
|
Attribute Filter¶
Assign point values
Polygon
Single value
Range Filter¶
Keep or reject values
Pipeline Strategy¶
Assign with filters.overlay
Filter with filters.range
Clipping (command)¶
1 | pdal pipeline ./exercises/analysis/clipping/clipping.json --nostream
|
Clipping (verify)¶

Other ways to clip¶
Clip using multiple filters.range
filters.divider or filters.chipper