GEOG 379 Lecture Notes - Lecture 13: Georeferencing, Arcgis
27 Apr 2018
School
Department
Course
Professor
Week 13
4/9 – Raster Processing
Raster Operations
• Georeferencing
o Giving spatial reference
• Resampling
o Changing cell size
• Reclassification
o Classifying cell values
• Raster calculation
o Doing mathematical operations
Georeferencing
• Assigning spatial reference to raster data
Resampling
• Changing cell size
o From large to small, or small to large cells
• Resampling method
o Mean
o Median
o Mode
Reclassification
• Assigning new value or reclassifying data
• Reclassify tool – classifies raster data values and assigns new values based on this calculation
Raster Calculation
• Applying calculation on raster layer
• Ex –
o Grid of factors favoring growth
▪ Planned annexation/ growth areas, active projects, near existing services and
infrastructure
+
o Grid of factors favoring preservation
▪ High value agricultural lands/forests, floodplains, proximity to correctional
facilities
=
o Statewide grid w/ values ranging from -11 to 20
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Raster operations: georeferencing, giving spatial reference, resampling, changing cell size, reclassification, classifying cell values, raster calculation, doing mathematical operations. Georeferencing: assigning spatial reference to raster data. Resampling: changing cell size, from large to small, or small to large cells, resampling method, mean, median, mode. Reclassification: assigning new value or reclassifying data, reclassify tool classifies raster data values and assigns new values based on this calculation. Local function acts on only one cell at a time: neighborhood function considers neighboring cell values when processing individual cells. Limits measurements to discrete distance bands: reconsidering buffers, distance/ cost surfaces, more versatile + provide continuous distance measurements at the cell level of resolution. Distance surfaces: using euclidean distance tool, measure straight-line distance b/w individual cells + input features. Identifies the closest input feature for each cell. It can convert raster data to vector data.
