cql_geom_predicates: CQL Geometry Predicates

In VicmapR: Access Victorian Spatial Data Through Web File Services (WFS)

CQL Geometry Predicates

Description

Functions to construct a CQL expression to be used to filter results from vicmap_query(). See the geoserver CQL documentation for details. The sf object is automatically simplified to a less complex sf object to reduce the complexity of the Web Service call. Subsequent in-memory filtering may be needed to achieve exact results.

Usage

EQUALS(geom)

DISJOINT(geom)

INTERSECTS(geom)

TOUCHES(geom)

CROSSES(geom)

WITHIN(geom)

CONTAINS(geom)

OVERLAPS(geom)

RELATE(geom, pattern)

BBOX(coords, crs = NULL)

DWITHIN(
  geom,
  distance,
  units = c("meters", "feet", "statute miles", "nautical miles", "kilometers")
)

BEYOND(
  geom,
  distance,
  units = c("meters", "feet", "statute miles", "nautical miles", "kilometers")
)

Arguments

geom	an sf/sfc/sfg or bbox object (from the sf package)
pattern	spatial relationship specified by a DE-9IM matrix pattern. A DE-9IM pattern is a string of length 9 specified using the characters ⁠*TF012⁠. Example: '1*T***T**'
coords	the coordinates of the bounding box as four-element numeric vector c(xmin, ymin, xmax, ymax), a bbox object from the sf package (the result of running sf::st_bbox() on an sf object), or an sf object which then gets converted to a bounding box on the fly.
crs	(Optional) A numeric value or string containing an SRS code. If coords is a bbox object with non-empty crs, it is taken from that. (For example, 'EPSG:3005' or just 3005. The default is to use the CRS of the queried layer)
distance	numeric value for distance tolerance
units	units that distance is specified in. One of "feet", "meters", "statute miles", "nautical miles", "kilometers"

Details

The code for these cql predicates was developed by the bcdata team: https://bcgov.github.io/bcdata/reference/cql_geom_predicates.html

Value

a CQL expression to be passed on to the WFS call

VicmapR documentation built on July 9, 2023, 7:34 p.m.