SDO_CS.TO

Format

SDO_CS.TO_USNG(
     geom               IN SDO_GEOMETRY, 
     accuracy_in_meters IN NUMBER, 
     datum              IN VARCHAR2 DEFAULT 'NAD83') RETURN VARCHAR2;

Description

Converts a spatial point geometry object to a point represented in U.S. National Grid format.

Parameters

geom: Point geometry whose representation is to be converted to a point represented in U.S. National Grid format. The input geometry must have a valid non-null SRID, that is, a value in the SRID column of the SDO_COORD_REF_SYS table (described in SDO_COORD_REF_SYS Table).
accuracy_in_meters: Accuracy of the point location in meters. Should be 1 raised to a negative or positive power of 10 (for example, 0.001, 0.01, 0.1, 1, 10, 100, or 1000). Any other specified values are adjusted internally by Spatial, and the result might not be what you expect.
datum: The name of the datum on which the U.S. National Grid coordinate for the point is to be based. Must be either NAD83 or NAD27. The default value is NAD83.

Usage Notes

For information about Oracle Spatial support for the U.S. National Grid, see U.S. National Grid Support.

The accuracy_in_meters value affects the number of digits used to represent the accuracy in the returned U.S. National Grid string. For example, if you specify 0.000001, the string will contain many digits; however, depending on the source of the data, the digits might not accurately reflect geographical reality. Consider the following scenarios. If you create a U.S. National Grid string from a UTM geometry, you can get perfect accuracy, because no inherently inaccurate transformation is involved. However, transforming from a Lambert projection to the U.S. National Grid format involves an inverse Lambert projection and a forward UTM projection, each of which has some inherent inaccuracy. If you request the resulting U.S. National Grid string with 1 millimeter (0.001) accuracy, the string will contain all the digits, but the millimeter-level digit will probably be geographically inaccurate.

To convert a point represented in U.S. National Grid format to a spatial point geometry, use the SDO_CS.FROM_USNG function.

Examples

The following example converts a spatial geometry point object with longitude/latitude coordinates to a point represented in U.S. National Grid format using an accuracy of 0.001 meter (1 millimeter).

-- Convert longitude/latitude (WGS 84) point to US National Grid.
SELECT SDO_CS.TO_USNG(
  SDO_GEOMETRY(2001, 4326,
    SDO_POINT_TYPE(-77.0352402158258, 38.8894673086544, NULL),
    NULL, NULL),
  0.001) FROM DUAL;
 
SDO_CS.TO_USNG(SDO_GEOMETRY(2001,4326,SDO_POINT_TYPE(-77.0352402158258,38.889467
--------------------------------------------------------------------------------
18SUJ2348316806479498