Spatio-temporal functions - Lindorm - Alibaba Cloud Documentation Center

This topic describes the spatio-temporal functions supported by Lindorm GanosBase.

Applicable engines and versions

The spatio-temporal functions described in this topic are applicable only to all versions of LindormTable.

Functions

The following table lists the spatio-temporal functions supported by Lindorm GanosBase.

Note

The names of the spatio-temporal functions are case-insensitive.

Category	Documentation	Description
Constructor functions	ST_GeomFromText	Constructs a geometry object based on the specified Well-known Text (WKT) string.
	ST_LineFromMultiPoint	Constructs a LineString object based on the specified MultiPoint object.
	ST_MakePoint	Constructs a point object.
Output functions	ST_AsText	Returns the information about a geometry object in Well-known Text (WKT) format.
Access functions	ST_Centroid	Returns the centroid of the specified geometry object.
	ST_EndPoint	Returns the last point of the specified LineString object.
	ST_NPoints	Returns the number of vertexes in the specified geometry object.
	ST_StartPoint	Returns the start point of the specified LineString object.
	ST_X	Returns the x coordinate of the specified point object.
	ST_XMax	Returns the maximum x coordinate on the bounding box of the specified geometry object.
	ST_XMin	Returns the minimum x coordinate on the bounding box of the specified geometry object.
	ST_Y	Returns the y coordinate of the specified point object.
	ST_YMax	Returns the maximum y coordinate on the bounding box of the specified geometry object.
	ST_YMin	Returns the minimum y coordinate on the bounding box of the specified geometry object.
Functions for spatial relationships	ST_Contains	Checks whether the first geometry object that you specify contains the second geometry object that you specify. If the first geometry object contains the second geometry object, this function returns true.
	ST_DWithin	Checks whether the 2D distance between two geometry objects is within the specified range. If the 2D distance between the objects is within the specified range, this function returns true.
	ST_DWithinSphere	Checks whether the spherical distance between two geometry objects is within the specified range. If the spherical distance between the objects is within the specified range, this function returns true.
	ST_Intersects	Checks whether two geometry objects intersect. If the two geometry objects have any shared spatial space, this function determines that the two objects intersect and returns true.
	ST_Overlaps	Checks whether two geometry objects spatially overlap but one is not included in the other. If the two geometry objects spatially overlap but one is not included in the other, this function returns true.
	ST_Within	Checks whether the second geometry object that you specify completely lies in the first geometry object that you specify. If the second geometry object completely lies in the first geometry object, this function returns true.
Aggregate functions	ST_Length_Rows	Returns the spherical length of the trajectory aggregated by all points in the specified point column. The unit of the returned value is meter. This function reads all points in the specified point column in the order of the primary keys, and then calculates the length of the trajectory aggregated by the points.
	ST_TrajectoryProfile	Calculates the trajectory aggregated by all points in the specified point column based on the order of time data in the specified time column, and returns the trajectory segments divided by a specific time threshold. This function is usually used together with functions for spatial relationship, such as ST_DWithinSphere. In this case, you can calculate the coordinates and time of the point that first enters a specified area and the point that last leaves a specified area in a trajectory segment.
	ST_Resample	Generates a trajectory by using the specified time points that are sorted in ascending order and downsampled based on the specified threshold.