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PolarDB:ST_RPCGeoreference

Last Updated:Mar 28, 2026

Returns a JSON string containing the rational polynomial coefficients (RPCs) of a raster object. If the raster object contains no RPC information, the function returns null.

Syntax

text ST_RPCGeoreference(raster raster_obj)

Parameters

ParameterTypeDescription
raster_objrasterThe raster object to query.

Return value

A JSON string with the following fields. All scalar values are floats; all coefficient fields are float arrays.

FieldTypeDescription
lineOfffloatThe line offset.
sampOfffloatThe sampling offset.
latOfffloatThe latitude offset.
longOfffloatThe longitude offset.
heightOfffloatThe height offset.
lineScalefloatThe line ratio.
sampScalefloatThe sampling ratio.
latScalefloatThe latitude ratio.
longScalefloatThe longitude ratio.
heightScalefloatThe height ratio.
lineDenCoefffloat arrayLine denominator coefficients. Valid values: 1 to 20.
lineNumCoefffloat arrayLine numerator coefficients. Valid values: 1 to 20.
sampNumCoefffloat arraySample numerator coefficients. Valid values: 1 to 20.
sampDenCoefffloat arraySample denominator coefficients. Valid values: 1 to 20.
errBiasfloatRMS bias errors in meters. These errors are related to all points per horizontal axis in an image. Default: -1.0.
errRandomfloatRMS random errors in meters. These errors are related to each point per horizontal axis in an image. Default: -1.0.
errBias and errRandom default to -1.0, which indicates that no error estimate is available for the raster object.

Example

SELECT ST_RPCGeoreference(raster_obj) FROM raster_table WHERE id = 1;

Output:

{
  "lineOff": 12800.0,
  "sampOff": 4008.0,
  "latOff": 55.0203,
  "longOff": 27.0478,
  "heightOff": 179.0,
  "lineScale": 12800.0,
  "sampScale": 4008.0,
  "latScale": 0.1238,
  "longScale": 0.0685,
  "heightScale": 300.0,
  "errBias": -1.0,
  "errRandom": -1.0,
  "lineDenCoeff": [1.0, -0.00050066513, -0.0014578309, 0.0006037474, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
  "lineNumCoeff": [-0.002104832, -0.01642616, -1.027459, 0.0041820025, -0.0019027952, 0.000016143133, 0.00047863558, -0.00021278669, 0.0069588307, -0.0000022605722, -2.2259552e-7, -3.7469372e-7, 0.00046486457, -1.8012888e-8, 0.000051407583, 0.00075661479, -5.4524409e-7, 1.3940799e-7, -0.000018281596, 2.4215581e-9],
  "sampDenCoeff": [1.0, -0.00050066513, -0.0014578309, 0.00060374744, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0],
  "sampNumCoeff": [1.0, -0.00050066513, -0.0014578309, 0.00060374744, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]
}

In this example, errBias and errRandom are both -1.0, which means the raster object has no error estimates stored.