Defines a spatial reference object based upon its well known identifier (WKID) and optionally a WKID for a vertical datum. The resolution and xy tolerances are either computed from the sr horizon or set to defaults. 'authority' is typically either 'EPSG' or 'E
[Visual Basic .NET] Public Function FindSRByWKID ( _ ByVal authority As String, _ ByVal WKID As Integer, _ ByVal WKID_Z As Integer, _ ByVal bDefaultXYResolution As Boolean, _ ByVal bDefaultXYTolerance As Boolean _ ) As ISpatialReference
[C#] public ISpatialReference FindSRByWKID ( string authority, int WKID, int WKID_Z, bool bDefaultXYResolution, bool bDefaultXYTolerance );
[C++]
HRESULT FindSRByWKID(
BSTR authority,
long WKID,
long WKID_Z,
VARIANT_BOOL bDefaultXYResolution,
VARIANT_BOOL bDefaultXYTolerance,
ISpatialReference** ppSR
);
[C++]Parameters
authority authority is a parameter of type BSTR WKID WKID is a parameter of type long WKID_Z WKID_Z is a parameter of type long bDefaultXYResolution bDefaultXYResolution is a parameter of type VARIANT_BOOL bDefaultXYTolerance bDefaultXYTolerance is a parameter of type VARIANT_BOOL ppSR [out, retval]ppSR is a parameter of type ISpatialReference
Product Availability
Remarks
Returns a predefined, high precision spatial reference based on its OGP/EPSG Well Known Identifier (WKID, aka “factory code”). Valid WKIDs are listed below. If WKID_Z > -1, then a vertical coordinate system will be created and associated with the horizontal coordinate system.
AuthorityName is usually "EPSG" or "ESRI", but can
also be an arbitrary string. It can also be the empty string if you
want the default authority name associated with the new spatial
reference. Clients can associate their own authority names with
factory codes that are currently associated with the EPSG or ESRI
authority names, because only the WKID is used to create the
spatial reference. Here are the current rules for mapping
WKID ranges to default authority names:
• A WKID in the EPSG code range (1000
– 32768) will result in an AUTHORITY name of
“EPSG”, and the version will be the current EPSG
version used (currently “6.12”).
• A WKID in the ESRI code range (33000 –
199999) will result in an AUTHORITY name of “ESRI”, and
the version will be the current PE library version (currently
“9.3”).
• A WKID in the user (objedit) range (200000
– 209199) will result in an AUTHORITY name of
“CUSTOM”, with no version associated with it.
This name is specified by the OGC.
For web service clients of the geometry server, the returned WKT (well known text) element of the spatial reference will have an “AUTHORITY’ tag in it, containing the default or the client-specified authority name and the specified WKID.
If bDefaultXYResolution is true, then the xy coordinate grid resolution will be set to its default value (see SetDefaultXYResolution for details). If it is false, the finest possible resolution that covers the horizon of the spatial reference will be used (see ConstructFromHorizon for details).
If bDefaultXYTolerance is true, then the default xy tolerance of 1mm will be used (see SetDefaultXYTolerance for details). If it is false, then the minimum xy tolerance will be used (2.0 * xy coordinate grid resolution).
Lists of the valid WKIDs for predefined Projected
Coordinate Systems can be found here:
esriSRProjCS2Type,
esriSRProjCS3Type,
esriSRProjCS4Type,
esriSRProjCSType
Lists of the valid WKIDs for predefined Geographic Coordinate Systems can be found here:
esriSRGeoCS2Type, esriSRGeoCS3Type, esriSRGeoCSType
Default XY Resolution values
SpatialReference type |
Precision |
Default value |
ProjectedCoordinateSystem |
high |
1/10 mm |
ProjectedCoordinateSystem |
low |
1 mm |
GeographicCoordinateSystem |
high |
1/10,000 arc-second |
GeographicCoordinateSystem |
low |
1/500 arc-second |
UnknownCoordinateSystem |
high |
1/10 mm |
UnknownCoordinateSystem |
low |
1 mm |
Defining an XY resolution
Defining an XY resolution for a spatial reference depends on the
type and precision of a coordinate system. For high precision
spatial references, the domain extent and resolution must be
sufficient to cover the horizon of a given coordinate system.
For low-precision spatial references the domain extent is
centered on the horizon center.
For a high precision ProjectedCoordinateSystem (PCS), the domain extent is a square completely covering, and slightly larger than, the horizon extent of the PCS (which is an arbitrary rectangle). The scale factor (1/precision) is chosen to fit this domain. For a low precision PCS, the center of the domain extent is aligned with the center of the horizon extent and expanded to achieve a target resolution of 1mm.
For a high precision GeographicCoordinateSystem (GCS), the square domain (-400, -400, 400, 400), expressed in the units of the spatial reference, is used. For a low precision GCS the upper right hand corner is adjusted to achieve a default resolution of 1/500 of an arc-second.
For an UnknownCoordinateSystem (UCS), the "horizon" is defined to be a square that produces a resolution of 1 millimeter for a low precision UCS or 1/10 mm for a high precision UCS.
Default XY Tolerance calculations
For a ProjectedCoordinateSystem or an UnknownCoordinateSystem, the
default tolerance is 1 mm (expressed in the units of the spatial
reference) or 2.0 * XYResolution, whichever is larger. For a
GeographicCoordinateSystem, it is the angle subtending 1 mm at the
equator, or 2.0 * XYResolution, whichever is larger.
The minimum allowable XYTolerance is 2.0 * XYResolution.
If the default XY tolerance is not greater than or
equal to 2.0 * XYResolution, the XYTolerance will be set at 2.0 *
XYResolution.