- Sorghum Exercise
- sorghum basics
- cereal crop
- needs moist soils
- clay soils
- periodic flooding
- raster data
- "grid of squares"
- similar to an excel spreadsheet
- each "box" = a pixel ... = cell
- each pixel (cell) is "independent" and holds a number
- each pixel has a fixed size ... = pixel resolution (e.g. 30m)
- x,y coordinates are applied to each axis - gives location
- raster data good for
- continuous data (as each cell is independent)
- elevation vs. soil types
- overlays (as raster layers have same dimensions/resolution)
- satelitte images (scanned images too)
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- ArcGIS House Keeping Chores
- map the GIS drive (G:\FRST328)
- copy the data to your account
- enable Spatial Analyst
- Explore the data
- dsoils
- drelief
- pixel resolution
- histogram (distribution) of pixel values
- alter the display ... so it is more intuitive
- Do the analysis
- 1) create intermediate maps
- create each (intermediate) layer
- then combine the layers
- 2) do it all at once (in a single formula)
- the model
- consider the raw data & desired end product
- figure out the steps (analyses) required to connect the two
- clay soils
- low lying flood area
- sometimes done working backwards
- want areas suitable for sorghum
- require clay soils & flood areas
- have raw soils & elevation
- ... need to "isolate" clay
- ... need to "isolate" flood"
- ... then combine clay + flood ... = sorghum
