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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.

Text of Aligning data

  • 1. Aligning dataSabata Mcatshulwa

2. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools 3. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools 4. Common Problems 5. Common Problems 6. Common Problems 7. Demonstration 8. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools 9. Coordinate SystemsGeographic Coordinate Systems A measurement of a location on the Earths surfaceexpressed in degrees of latitude and longitude 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. Coordinate SystemsProjected Coordinate Systems A method by which the curved surface of the earth is portrayed on a flat surface 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. Coordinate SystemsDatums A frame of reference for measuring locations on the surfaceof the Earth Cape (Port Elizabeth) Hartebeesthoek 1994 (Hartrao) WGS 1984 (Earth-centered = mass of the Earth) 14. TM Two degree zones (Transverse Mercator) LO = TM x, Cape WG = TM x, Hartebeesthoek 15. Coordinate Systems South Africa or a different area Create a .prj file Update the parameters 16. Demonstration 17. Presentation Outline Common problems Coordinate Systems Geoprocessing Tools 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. Geoprocessing Tools Spatial adjustment Projections - Shift data between coordinate systems Transformations - Shift data in coordinate space Alignment tools Bulk alignmentSnap - snapping based on user specified rulesIntegrate will make feature coincident within a tolerance Interactive(New tools introduced at 10.1)Align Edge - snap edges together to close gapsAlign to shape - adjust layers to traced shapeReplace geometry - create an entire new shape for a feature 20. Demonstration 21. Discussion

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