Geoprocessing functions
Geometry processing functions
The following built-in RiskScape functions are provided for creating or manipulating data that is of geometry
type.
For more details, see riskscape function list -c geometry_processing
.
buffer
Implements buffer geometric function as per the GeoTools reference
centroid
Implements centroid geometric function as per the GeoTools reference
create_point
Creates a geometry point using the given x, y coordinate
geom_from_wkt
Implements
geomFromWKT
geometric function as per the GeoTools referenceintersection
Implements intersection geometric function as per the GeoTools reference
measure
Will measure either the length or area of a geometry, depending on its geometry type. Points will always return 0. Lines will return the length as per
measure_length
. Polygon’s will return the area as permeasure_area
.GeometryCollections
will return the sum of all geometries in the collectionmeasure_area
Measure the area of geometry in metres squared (m²). Note that geometries that are specified in degrees are reprojected before being measured. This will lose accuracy for geometries that are larger than 6° in either direction and eventually fail if too big.
measure_length
Measure the length of a geometry’s perimeter in metres (m). Note that geometries that are specified in degrees are reprojected before being measured. This will lose accuracy for geometries that are larger than 6° in either direction and eventually fail if too big.
sample
Select values from a coverage
sample_centroid
Select a single value from a coverage
segment
Cut a geometry up by a distance specified in metres (m). Polygons are cut in to squares with area
distance m²
, linestrings are cut in to pieces of at mostdistance
m in length.
Logical geometry functions
The following built-in RiskScape functions are provided for testing how geometry
data types relate to each other,
as per the GeoTools spatial predicates.
For more details, see riskscape function list -c geometry_logical
.
bbox
beyond
contains
crosses
disjoint
dwithin
equals
intersects
overlaps
relate
touches
within