The Joy of GRID: Geomorphology and Hydrology in GIS Finn Krogstad UW Forest Engineering http:// students.washington.edu
Dec 21, 2015
The Joy of GRID:Geomorphology and Hydrology in GIS
Finn Krogstad
UW Forest Engineering
http://students.washington.edu
Times Change
• Spatial problems used to require lots of programming.
• With modern spreadsheets, we could assign it as an undergraduate homework problem.
• GRID offers the same spreadsheet simplicity and functionality,but handles spatial issues for you.
OUTLINE
A. GRID BASICS1. GIS Data2. Thinking in GRID3. Programming
B. HYDROLOGIC PROCESSES1. Local2. Watershed
C. ANALYSIS1. Classification 2. Regression
GRID BASICS - Thinking in GRID
• GRID-ing the World
• Grid Algebra
• Spatial Spreadsheet
- not mysterious
- intuitiveness
- flexible
GRID BASICS - Programming
• Command Line– just like you type it
• Flow Control– if, do, while
• User Interface– for GIS novices, e.g. SEDMODL
Hydrologic Processes• Local
– Slope, Aspect, Curvature
Z = Ax2y2 + Bx2y + Cxy2 + Dx2 + Ey2 + Fxy + Gx + Hy + I
Hydrologic Processes• Local
– Slope, Aspect, Curvature– Hillshade
• Display Topography
• Radiant Energy
• Other things
Hydrologic Processes• Local
• Watershed– Flow direction– Flow accumulation
• Upslope Area
• Streams
• Watersheds
• Variable Inputs
• Cumulative Impact
Hydrologic Processes• Local
• Watershed– Flow direction– Flow accumulation– Flow length
• distance to stream
• transport ‘friction’
• delivery to streams
Classification vs. End Member
Classification - We can classify a cell according to which class gives a higher likelihood.
End Member - The fraction of each end member can be approximated by saving the normalized likelihoods.
Multivariate Analysis
• Clustering
• Regression• Linear
Ey = a0+ a1x1 + a2x2 + a3x3 + ....
E(precip) = a0+ a1longitude + a2elevation
Multivariate Analysis
• Clustering
• Regression• Linear
Ey = a0+ a1x1 + a2x2 + a3x3 + .…
• Logistic
Ey=1/(1+(exp(-(a0+alxl+a2x2+a3x3+...)))
L-0.0018M-0.0026H-0.0037
LandslideProbability
E(LS)=1/(1+(exp(-(a0+alSMORPH)))
Conclusions• GRID should be used like Excel
• Get yourself a wonk
• Keep up on data sources
• Use models to predict results
• Use observations to improve models
Final Exam10:30-12:20 p.m. Wednesday, Mar. 15, 2000
open books, open notes, pencil-and-paper solution/discussion of several problems.
LabsPost lab reports on their web site
Grading will be based on communication
Finished and posted one week after assigned.
Late work will be accepted with half the points deduced for each week it is late.
Revise and resubmit each lab.