ST_summary-PolarDB(PolarDB)-阿里云帮助中心

Returns a JSON-formatted summary of a pcpatch object, including patch-level metadata and per-dimension statistics.

Syntax

text ST_summary(pcpatch pc);

Parameters

Parameter	Description
`pc`	The pcpatch object.

Examples

SELECT ST_Summary(pa) FROM patches LIMIT 1;

Output:

{"pcid":1, "npts":9, "srid":4326, "compr":"dimensional","dims":[{"pos":0,"name":"X","size":4,"type":"int32_t","compr":"sigbits","stats":{"min":-126.99,"max":-126.91,"avg":-126.95}},{"pos":1,"name":"Y","size":4,"type":"int32_t","compr":"sigbits","stats":{"min":45.01,"max":45.09,"avg":45.05}},{"pos":2,"name":"Z","size":4,"type":"int32_t","compr":"sigbits","stats":{"min":1,"max":9,"avg":5}},{"pos":3,"name":"Intensity","size":2,"type":"uint16_t","compr":"rle","stats":{"min":0,"max":0,"avg":0}}]}

Output fields

The returned JSON contains the following fields.

Patch-level fields

Field	Description
`pcid`	The point cloud schema ID.
`npts`	The number of points in the patch.
`srid`	The spatial reference ID.
`compr`	The patch-level compression algorithm.
`dims`	An array of per-dimension descriptors.

Per-dimension fields (each element of `dims`)

Field	Description
`pos`	The dimension index (0-based).
`name`	The dimension name, for example, `X`, `Y`, `Z`, or `Intensity`.
`size`	The storage size in bytes.
`type`	The data type, for example, `int32_t` or `uint16_t`.
`compr`	The dimension-level compression algorithm.
`stats`	The statistical summary across all points in the patch, including `min`, `max`, and `avg` values.