gus: 0262 fundamentals of gis lecture presentation 8: data input and editing jeremy mennis...
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GUS: 0262Fundamentals of GIS
Lecture Presentation 8:
Data Input and Editing
Jeremy Mennis
Department of Geography and Urban Studies
Temple University
Raster Data Input
1. Vector to Raster Conversion
2. Scanned Graphics
3. Classified Remotely Sensed Imagery
4. Interpolation from Point Data
Raster to Vector Conversion
Scanned Graphics
Classified RS Imagery
Interpolation from Point Data
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Vector Data Input
1. Raster to Vector Conversion
2. Scanned Graphics (Scan Digitizing)
3. Data Collection from the Field
4. Manual Vector Digitizing
Scanned Graphics (Scan Digitizing)
1. Drum scanner scans in map image
2. Specialized software ‘extracts’ point, line, and area features
3. Very expensive and susceptible to errors when map is ‘dirty’
Field Data Collection
Field Data Collection
Manual Vector Digitizing Tablet
Manual Vector Digitizing Puck
Manual Vector Digitizing
1. Prepare map sheet
2. Digitize the coverage
3. Identify and correct digitizing errors
4. Build topology
5. Identify and correct topology errors
6. Assign attributes
7. Identify and correct attribute errors
Manual Vector Digitizing Process
Manual Vector Digitizing Preparation
1. Map quality?
2. Separations?
3. Folds and wrinkles in the map?
4. Transfer to mylar ?
Manual Vector Digitizing Preparation
Manual Vector Digitizing Registration
Manual Vector Digitizing Process
1. Fuzzy tolerance.
2. Try to capture the necessary accuracy with minimum number of data points.
Vector Data Editing
Vector digitizing errors
1. entity error (positional error)
2. attribute error
3. entity-attribute error
Undershoots/Overshoots
Weird Polygons
Missing node
Pseudonodes
pseudonode
Polygon Label Errors
Sliver Polygons
Edge Matching