View or change the properties of a spatial reference system.
Database Version | Spatial Reference System Privileges |
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SAP Sybase IQ 15.3 and 15.4 |
View spatial reference system properties – None required. Modify spatial reference system properties or comments – Requires one of:
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SAP Sybase IQ 16.0 |
View spatial reference system properties – None required. Modify spatial reference system properties – Requires one of:
Modify spatial reference system comment – Requires one of:
|
Area | Description |
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General page |
Name — Name of the selected spatial reference system. Spatial reference system ID — Numeric identifier for
your spatial reference system. When you create a spatial reference system
based on an existing spatial reference system, set the SRID value to be
1000000000 plus the Well Known value.
Note: SRSIDs 0, 2147483646, and
2147483647 are restricted.
Organization — The name of the organization that defined the spatial reference system. Organization coordinate reference system ID — The integer identifier assigned by the organization that defined the spatial reference system. Comment — A text field for adding an optional comment about the spatial reference system. |
Settings page |
Spatial reference system type — Either Geographic or Non-geographic. Line interpretation — (Applies only to geographic
spatial reference system type.)
Axis order — Order of axis in the spatial reference system; for example: Long./Lat./Z/M. Not editable. Polygon format — Specifies the orientation of polygon
rings of the input data. Internally, SAP Sybase IQ interprets polygons by
looking at the orientation of the constituent rings. As one travels a ring
in the order of the defined points, the inside of the polygon is on the left
side of the ring. The same rules are applied in planar and round earth
spatial reference systems.
Storage format — When you insert spatial data into
the database from an external format (such as WKT or WKB), the database
server normalizes the data to improve the performance and semantics of
spatial operations. The normalized representation may differ from the
original representation (for example, in the orientation of polygon rings or
the precision stored in individual coordinates). While spatial equality is
maintained after the normalization, some original input characteristics may
not be reproducible, such as precision and ring orientation. In some cases
you may want to store the original representation, either exclusively, or in
addition to the normalized representation.
Semi-major axis — (Applies only to geographic spatial reference system type.) The Earth is not a perfect sphere because the rotation of the Earth causes a flattening so that the distance from the center of the Earth to the North or South pole is less than the distance from the center to the equator. For this reason, the Earth is modeled as an ellipsoid with different values for the semi-major axis (distance from center to equator) and semi-minor axis (distance from center to the pole). It is most common to define an ellipsoid using the semi-major axis and the inverse flattening, but it can instead be specified using the semi-minor axis (for example, this approach must be used when a perfect sphere is used to approximate the Earth). Inverse flattening — (Applies only to geographic
spatial reference system type.) The inverse flattening (1/f) is a
ratio:
1/f = (semi-major-axis) / (semi-major-axis - semi-minor-axis)f measures symmetry axis compression relative to the equatorial radius of the ellipsoid. |
Coordinates page |
Latitude — (Applies only to geographic spatial
reference system type.)
Longitude — (Applies only to geographic spatial
reference system type.)
X — (Applies only to non-geographic spatial reference
system type.) X-coordinate value of a geometry.
Y — (Applies only to non-geographic spatial reference
system type.) Y-coordinate value of a geometry.
Z — Z-coordinate value of a geometry.
M — M-coordinate value of a geometry.
Snap to grid — (Planar line interpretation only.) The action of positioning the points in a geometry so they align with intersection points on a grid. When aligning a point with the grid, the X and Y values may be shifted by a small amount - similar to rounding. In the context of spatial data, a grid is a framework of lines that is laid down over a two-dimensional representation of a spatial reference system.. Tolerance — Tolerance defines the distance within which two points or parts of geometries are considered equal. This can be thought of as all geometries being represented by points and lines drawn by a marker with a thick tip, where the thickness is equal to the tolerance. Any parts that touch when drawn by this thick marker are considered equal within tolerance. If two points are exactly equal to tolerance apart, they are considered not equal within tolerance. Linear unit of measure — Select a unit of measure. Angular unit of measure — Select a unit of measure. |
Transform definition |
Transform definition — The spatial reference system transform definition text. Not editable. |