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# Aligning data

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The main focus of this presentation is on coordinate systems. We describe common problems that people have, key terms , how to apply coordinate systems in 10.1 and best practices.

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### Aligning data

1. 1. Aligning dataSabata Mcatshulwa
2. 2. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools
3. 3. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools
4. 4. Common Problems
5. 5. Common Problems
6. 6. Common Problems
7. 7. Demonstration
8. 8. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools
9. 9. Coordinate SystemsGeographic Coordinate Systems• A measurement of a location on the Earth’s surface expressed in degrees of latitude and longitude
10. 10. Coordinate SystemsGeographic Coordinate Systems • Three-dimensional spherical surface to define locations on the earth • If two datasets are not referenced to the same geographic coordinate system, you may need to perform a geographic (datum) transformation • It is very important to correctly use a geographic transformation if it is required. • A GCS is often incorrectly called a datum, but a datum is only one part of a GCS. A GCS includes an angular unit of measure, a prime meridian, and a datum (based on a spheroid). • The spheroid defines the size and shape of the earth model, while the datum connects the spheroid to the earths surface
11. 11. Coordinate SystemsProjected Coordinate Systems • A method by which the curved surface of the earth is portrayed on a flat surface
12. 12. Coordinate SystemsProjected Coordinate Systems • Two-dimensional surface • locations are identified by x,y coordinates on a grid, with the origin at the center of the grid • Unlike a GCS, a PCS has constant lengths, angles, and areas across the two dimensions • A PCS is always based on a GCS that is based on a sphere or spheroid.
13. 13. Coordinate SystemsDatums• A frame of reference for measuring locations on the surface of the Earth • Cape (Port Elizabeth) • Hartebeesthoek 1994 (Hartrao) • WGS 1984 (Earth-centered = mass of the Earth)
14. 14. TM• Two degree zones (Transverse Mercator) • LO = TM x, Cape • WG = TM x, Hartebeesthoek
15. 15. Coordinate Systems• South Africa or a different area• Create a .prj file• Update the parameters
16. 16. Demonstration
17. 17. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools
18. 18. Geoprocessing Tools• Vector • Define Projection = To assign a coordinate system • Project = Change a coordinate system• Raster • Raster Properties = To assign a coordinate system • Project Raster = Change a coordinate system
19. 19. Geoprocessing Tools − Spatial adjustment • Projections - Shift data between coordinate systems • Transformations - Shift data in coordinate space − Alignment tools • Bulk alignment Snap - snapping based on user specified rules Integrate – will make feature coincident within a tolerance • Interactive(New tools introduced at 10.1) Align Edge - snap edges together to close gaps Align to shape - adjust layers to traced shape Replace geometry - create an entire new shape for a feature
20. 20. Demonstration
21. 21. Discussion