Static Point Clouds

Static Point Clouds
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The static types come from pgPointCloud. MobilityDB exposes the schema-aware coordinate accessors needed to project pgPointCloud values into the rest of the temporal-types ecosystem.

Constructors

pgPointCloud's pcpoint_in only accepts hex-WKB, so the canonical builder is PC_MakePoint(pcid, ARRAY[…]::float[]). MobilityDB ships two thin SQL overloads on top of it for shorter test literals and ad-hoc queries; the underlying schema-dimension validation still happens inside PC_MakePoint.

Build a 2D or 3D pcpoint directly from x/y(/z) coordinates

pcpoint(pcid integer,x float,y float) → pcpoint
pcpoint(pcid integer,x float,y float,z float) → pcpoint

SELECT pcpoint(1, 10.0, 20.0, 30.0);
-- Equivalent to pcpoint(1, 10.0, 20.0, 30.0)

Build a pcpoint from the coordinates of every dimension of the schema
```
pcpoint(pcid integer,coordinates float[]) → pcpoint
```
The layout of the schema states every dimension, inactive ones included, which is how a schema of more dimensions than the overloads above reach is given its values. That count is the one PC_MakePoint takes and is NOT the count of active dimensions that pointCloudSchemaNDims reports
```
SELECT pcpoint(1, ARRAY[10.0, 20.0, 30.0]::float[]);
```
Build a pcpatch from the coordinates of its points, one point after another
```
pcpatch(pcid integer,coordinates float[]) → pcpatch
```
Every dimension of the layout of the schema is given for each point, inactive ones included. That count is the one PC_MakePatch takes and is NOT the count of active dimensions that pointCloudSchemaNDims reports; a count that divides evenly by the wrong one of the two builds a patch of the wrong points rather than reporting an error. A patch built this way states the schema itself, there being no point to read it from
```
SELECT pcpatch(1, ARRAY[1.0, 1.0, 1.0, 2.0, 2.0, 2.0]::float[]);
```

Build a pcpatch from a variadic list of pcpoints sharing the same pcid

pcpatch(VARIADIC points pcpoint[]) → pcpatch

SELECT pcpatch(pcpoint(1, 1.0, 1.0, 1.0), pcpoint(1, 2.0, 2.0, 2.0));
-- Equivalent to pcpatch(pcpoint(1, 1.0, 1.0, 1.0), pcpoint(1, 2.0, 2.0, 2.0))

Accessors

Return the schema id of a pcpoint or pcpatch

pcid({pcpoint,pcpatch}) → integer

SELECT pcid(pcpoint(1, 10.0, 20.0, 30.0));
-- 1

Return a coordinate of a pcpoint, NULL if the dimension is absent from the schema

getX(pcpoint) → float
getY(pcpoint) → float
getZ(pcpoint) → float

WITH pt AS (SELECT pcpoint(1, 10.0, 20.0, 30.0) p)
  SELECT getX(p), getY(p), getZ(p) FROM pt;
-- 10 | 20 | 30

Return any named dimension of a pcpoint, NULL if the name is unknown for the schema

getDim(pcpoint,text) → float

SELECT getDim(pcpoint(1, 10.0, 20.0, 30.0), 'X');
-- 10

Return the spatial reference identifier (inherited from the schema)

SRID({pcpoint,pcpatch}) → integer

SELECT SRID(pcpoint(1, 10.0, 20.0, 30.0));
-- 0
SELECT SRID(pcpatch(pcpoint(1, 10.0, 20.0, 30.0), pcpoint(1, 11.0, 21.0, 31.0)));
-- 0

Return the multipoint of the positions the points of a patch occupy
```
geometry(pcpatch) → geometry
```
The schema the pcid names decides the SRID and whether the result carries a Z dimension
```
SELECT ST_AsText(geometry(pcpatch(pcpoint(1, 1, 1, 1), pcpoint(1, 2, 2, 2))));
-- MULTIPOINT Z ((1 1 1),(2 2 2))
```