Filters all pcpoint objects in a pcpatch and returns a new pcpatch containing only the points whose value for the specified attribute dimension is less than a given threshold.
Syntax
pcpatch ST_filterLessThan(pcpatch pc, text dimname, float8 value);Returns: pcpatch
Parameters
| Parameter | Description |
|---|---|
pc | The input pcpatch object. |
dimname | The name of the attribute dimension to filter on. |
value | The threshold value. Only points whose dimension value is strictly less than this value are included in the result. |
Example
Filter all points in patch 7 where the y dimension is less than 45.60:
SELECT ST_AsText(ST_FilterLessThan(pa, 'y', 45.60)) FROM patches WHERE id = 7;Output:
{"pcid":1,"pts":[[-126.42,45.58,58,5],[-126.41,45.59,59,5]]}Both returned points have y values of 45.58 and 45.59, which are less than the threshold 45.60.
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