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SQL Anywhere 17 » SQL Anywhere Server - Database Administration » Database configuration » Database options » Alphabetical list of database options

st_geometry_interpolation option

Controls interpolation when spatial calculations involve circular arcs.

Allowed values

This database option takes a semicolon delimited set of key=value pairs (key1=value1;key2=value2;...). Allowed keys are relative-tolerance-percent and absolute-tolerance.

  • relative-tolerance-percent=DOUBLE

    Use relative-tolerance-percent to specify the maximum variation, expressed as a percent, allowed in the distance from the center point of the ST_CircularString segment to the interpolated ST_LineString segment, relative to the radius of the ST_CircularString segment. The minimum allowed value for relative-tolerance-percent is 0, meaning the absolute-tolerance setting is always used.

  • absolute-tolerance=DOUBLE

    Use absolute-tolerance to specify the maximum absolute variation, expressed in linear units, allowed in the distance from the center point of the ST_CircularString segment to the interpolated ST_LineString segment. The minimum value allowed for absolute-tolerance is also the tolerance specified by the SRID.

Defaults

If neither key is specified, relative-tolerance-percent defaults to 0.3, which gives 40 points in a complete circle, and absolute-tolerance defaults to the tolerance specified by the SRID.

If only one key is specified, the other key is set to its minimum value.

If both keys are specified, the minimum number of points is produced such that all restrictions are satisfied.

Default

relative-tolerance-percent=.3

Scope
  PUBLIC role For current user For other users
Allowed to set permanently? Yes, with SET ANY PUBLIC OPTION Yes Yes, with SET ANY PUBLIC OPTION
Allowed to set temporarily? Yes, with SET ANY PUBLIC OPTION Yes (current connection only) No
Remarks

Regardless of the setting for this database option, there are at least three points per curve segment. Furthermore, no two consecutive points on the interpolated ST_LineString are within tolerance of each other.

Additional points may be added to ensure the ST_Envelope of the ST_LineString is the same as that of the original ST_CircularString.