Spatial functions can be used with geospatial data. For example, they allow you to
calculate the distances between two points, the area of a polygon, and so on.
There can also be situations that require a merge of multiple geospatial data sets that are based
on a spatial predicate (within, close to, and so on), which can be done through a merge
condition.
Notes:
These spatial functions don't apply to three-dimensional data. If you import three-dimensional
data into a flow, only the first two dimensions are used by these functions. The z-axis values are
ignored.
Geospatial functions aren't supported.
Table 1. CLEM spatial functions
Function
Result
Description
close_to(SHAPE,SHAPE,NUM)
Boolean
Tests whether 2 shapes are within a certain DISTANCE of each other. If a projected coordinate
system is used, DISTANCE is in meters. If no coordinate system is used, it is an arbitrary
unit.
crosses(SHAPE,SHAPE)
Boolean
Tests whether 2 shapes cross each other. This function is suitable for 2 linestring shapes,
or 1 linestring and 1 polygon.
overlap(SHAPE,SHAPE)
Boolean
Tests whether there is an intersection between 2 polygons and that the intersection is
interior to both shapes.
within(SHAPE,SHAPE)
Boolean
Tests whether the entirety of SHAPE1 is contained within a POLYGON.
area(SHAPE)
Real
Returns the area of the specified POLYGON. If a projected system is used, the function
returns meters squared. If no coordinate system is used, it is an arbitrary unit. The shape must be
a POLYGON or a MULTIPOLYGON.
num_points(SHAPE,LIST)
Integer
Returns the number of points from a point field (MULTIPOINT) which are contained within the
bounds of a POLYGON. SHAPE1 must be a POLYGON or a MULTIPOLYGON.
distance(SHAPE,SHAPE)
Real
Returns the distance between SHAPE1 and SHAPE2. If a projected coordinate system is used, the
function returns meters. If no coordinate system is used, it is an arbitrary unit. SHAPE1 and SHAPE2
can be any geo measurement type.
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