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   region-1 as cts.region,
   region-2 as cts.region,
   [options as String[]]
) as Boolean


Compares geospatial regions to see if they fulfill the 'covers' DE-9IM relation.

region-1 The first geospatial region to compare. This region is the left operand of covers.
region-2 The second geospatial region to compare. This region is the right operand of covers.
options Options to this operation. The default is (). Available options:
Use the given coordinate system. Valid values are:
The WGS84 coordinate system with degrees as the angular unit.
The WGS84 coordinate system with radians as the angular unit.
The WGS84 coordinate system at double precision with degrees as the angular unit.
The WGS84 coordinate system at double precision with radians as the angular unit.
The ETRS89 coordinate system.
The ETRS89 coordinate system at double precision.
The raw (unmapped) coordinate system.
The raw coordinate system at double precision.
Use the coordinate system at the given precision. Allowed values: float and double.
Measure distance, radii of circles, and tolerance in the specified units. Allowed values: miles (default), km, feet, meters.
Tolerance is the largest allowable variation in geometry calculations. If the distance between two points is less than tolerance, then the two points are considered equal. For the raw coordinate system, use the units of the coordinates. For geographic coordinate systems, use the units specified by the units option.

Usage Notes

This function determines whether the two regions R1=region-1 and R2=region-2 satisfy the relationship R1 covers R2.

The operations are defined by the Dimensionally Extended nine-Intersection Model (DE-9IM) of spatial relations.

The value of the precision option takes precedence over that implied by the governing coordinate system name, including the value of the coordinate-system option. For example, if the governing coordinate system is "wgs84/double" and the precision option is "float", then the operation uses single precision. If region-1 or region-2 is a column, the column's coordinate system will take precedence over the coordinate-system option. If both region-1 and region-2 are columns, the query will run unoptimized. Queries with one region column and a region literal will be optimized.

See Also


const r1 = cts.polygon('POLYGON((-122.38582892471908 37.61827880006116,-122.4143247132933 37.60685626556358,-122.40436835343002 37.59352775797751,-122.38582892471908 37.61827880006116))');
const r2 = cts.polygon('POLYGON((-122.427520751953 37.6555576956251,-122.459106445313 37.5658069549294,-122.289505004883 37.5946477878735,-122.427520751953 37.6555576956251))');

// returns true


// Optic example using the Value Processing Function op.geo.covers()
const op = require('/MarkLogic/optic');
var polygonLit =
    `POLYGON((-109.05489567149378 37.007687849517886,-109.05489567149378 31.321594772151634,
    -108.19796207774378 31.39664652828848,-108.26388004649378 31.827028203476246,
    -106.52804020274378 31.808357379968474,-106.55001285899378 32.08802274501026,
    -103.03438785899378 32.03215780670212,-103.01241520274378 37.025232193318125,
    -109.05489567149378 37.007687849517886))`
const result=op.fromView('buildings', 'builds')
               .select([op.col('name'), op.col('geoid')])
// ==>
// rows representing names and geoids where the 'poly' column COVERS polygonLit (a rough New Mexico representation)


'use strict';
// SQL example using the ST_Covers function
const literal = 
      `POLYGON((-83.74086287706339 35.30705888366864,
      -82.57081893175089 35.30705888366864,
      -82.57081893175089 33.64983884507408,
      -83.74086287706339 33.64983884507408,
      -83.74086287706339 35.30705888366864))`}

var result = xdmp.sql('select * from builds where ST_Covers(poly,@polyLit) order by geoid limit 20', null, literal);

// ==>
// returns rows whose 'poly' column match the DE-9IM relationship COVERS the provided WKT polygon


'use strict';
const op = require('/MarkLogic/optic');
// GeoSPARQL example using geof:sfCovers()
var poly = 
    'POLYGON((-83.74086287706339 35.30705888366864,-82.57081893175089 35.30705888366864,\
     -82.57081893175089 33.64983884507408,-83.74086287706339 33.64983884507408,\
     -83.74086287706339 35.30705888366864))'

var query = 
PREFIX my: <http://example.org/ApplicationSchema#>
PREFIX geoml: <http://marklogic.com/geospatial#>
PREFIX cts: <http://marklogic.com/cts#>
PREFIX geof: <http://www.opengis.net/def/function/geosparql/>
WHERE { ?s my:hasExactGeometry ?o
  FILTER geof:sfCovers(?o, ?poly, 'coordinate-system=wgs84')

// ==>
// rows representing geometries in a triple's object in the wgs84 coordinate system
// that fulfill the COVERS DE-9IM relation with the WKT polygon 'poly', ordered by subject

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