The Polygon
datatype represents a shape on the Earth as a ring of WGS84 Latitude and Longitude pairs. The location is encoded as a GeoJSON “polygon”. Example:
coordinates
property, GeoJSON orders the coordinates as "longitude, latitude" (X coordinate, Y coordinate), as other GIS coordinate systems are encoded. Note that the SoQL within_box
and within_circle
functions use the more conventional ordering, however.
The following operators can be used on polygon
fields:
Operator | Description |
---|---|
IS NULL |
TRUE for values that are NULL . |
IS NOT NULL |
TRUE for values that are not NULL . |
And the following functions can be used with them:
Keyword Name | Description | Availability |
---|---|---|
distinct |
Returns distinct set of records | 2.1 |
Function Name | Description | Availability |
---|---|---|
case(...) |
Returns different values based on the evaluation of boolean comparisons | 2.1 |
convex_hull(...) |
Returns the minimum convex geometry that encloses all of another geometry | 2.1 |
count(...) |
Returns a count of a given set of records | 2.0 and 2.1 |
extent(...) |
Returns a bounding box that encloses a set of geometries | 2.1 |
intersects(...) |
Allows you to compare two geospatial types to see if they intersect or overlap each other | 2.1 |
num_points(...) |
Returns the number of vertices in a geospatial data record | 2.1 |
simplify(...) |
Reduces the number of vertices in a line or polygon | 2.1 |
simplify_preserve_topology(...) |
Reduces the number of vertices in a line or polygon, preserving topology | 2.1 |
within_box(...) |
Returns the rows that have geodata within the specified box, defined by latitude, longitude corners | 2.0 and 2.1 |
within_circle(...) |
Returns the rows that have locations within a specified circle, measured in meters | 2.0 and 2.1 |
within_polygon(...) |
Returns the rows that have locations within the specified box, defined by latitude, longitude corners | 2.1 |
Closely related to the Polygon datatype is the MultiPolygon
.