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== Spatial Reference Systems (SRS) == * Spatial Reference Systems - coordinate system to identify particular points on the earth (e.g. WGS84) * geoid - the word used to describe the shape of the earth. * reference ellipsoid - a smooth model used by scientists to approximate the shape of the earth. * oblate spheroid - most commonly used reference ellipsoid * Most reference ellipsoids aren't meant to model the entire earth, but some such as the World Geodetic System 1984 do. * SQL Server 2012 recognizes spatial reference systems based on a number of different reference ellipsoids. || Ellipsoid Name || Semi-Major Axis (m) || Semi-Minor Axis (m) || Inverse Flattening || Area of Use || || Airy (1830) || 6,377,563.396 || 6,356,256.909 || 299.3249646 || Great Britain || || Bessel (1841) || 6,377,397.155 || 6,356,078.963 || 299.1528128 || Czechoslovakia, Japan, South Korea || || Clarke (1880) || 6,378,249.145 || 6,356,514.87 || 293.465 || Africa || || NAD 27 || 6,378,206.4 || 6,356,583.8 || 294.9786982 || North America|| || NAD 83 || 6,378,137 || 6,356,752.3 || 298.2570249 || North America|| || WGS 84 || 6,378,137 || 6,356,752.314 || 298.2572236 || Global|| The above table demonstrates the Size/Shape characteristics of a SRS. To complete the package we need ''reference points'' to place the ellipsoid in the correct position relative to the earth. '''Definition [Spatial Reference System]''' A geodetic datum is made up of a reference ellipsoid and a set of reference points to position the ellipsoid relative to the earth. === Geographic Coordinate Systems === * Latitude - 0 degrees at equator, 90 degrees at the north pole, -90 degrees at the south pole. * Longitude - 0-180 degrees east or west <<attachment:latlong.png>> |
* Chapter 1: /SpatialReferenceSystems * Chapter 2: /SpatialFeatures * Chapter 3: /SpatialDataTypes * Chapter 4: /CreatingSpatialData * Chapter 5: /ImportingSpatialData * Chapter 6: [[/Geocoding]] * Chapter 7: /PrecisionValidityAndErrors * Chapter 8: /TransformationAndReprojection |
Geographic Information Systems Notes
In 2014, CPTR 521 used Pro Spatial with SQL Server 2012 to study spatial data in SQL Server 2012. This page documents that experience.
Chapter 1: /SpatialReferenceSystems
Chapter 2: /SpatialFeatures
Chapter 3: /SpatialDataTypes
Chapter 4: /CreatingSpatialData
Chapter 5: /ImportingSpatialData
Chapter 6: /Geocoding
Chapter 7: /PrecisionValidityAndErrors
Chapter 8: /TransformationAndReprojection