Automating Analyses with ModelBuilder

1. Automating Analyses with ModelBuilder

2. Overview • Why Use ModelBuilder? • ModelBuilder Basics • Common ModelBuilder Problems • Advanced ModelBuilder

3. Why Use ModelBuilder? • An automation tool… • But comes with some startup overhead • Most useful in two circumstances • Documents models & their parameterization • Allows experimentation with model parameters – particularly for “weighting and rating” • Common Types of Models • ETL – Extract, transform and convert raw data • Suitability – Building attractiveness maps

4. ModelBuilder Basics • Basic idea is that of a “dependency diagram” • User specifies inputs, processing and outputs • If inputs change, system repeats intermediate operations as needed • Diagram has three kinds of elements • Inputs • Geoprocessing Operations • Outputs • Output from one operation can be used as input to an other, allowing “chaining”

5. ModelBuilder Setup • Rather obscure to start…implemented as a custom toolbox tool • Open toolbox panel • Create empty toolbox • Right mouse on Toolboxes, select New Toolbox • Create empty model • Right mouse on new Toolbox, select New Model • Then populate model by drag and drop • Of data layers from map table of contents • Of geoprocessing operations from the toolbox • Finally, wire data and processing boxes together

6. Example: Simple MB Model • Goal • Create a factor map expressing simple proximity to residential landuse where output is classed from 1..9 • Method • Create new model • Add residential landuse • Add Euclidean distance geoprocessing operation • Connect landuse (input) to distance (process), specifying new grid (output) • Run • Add Reclass Operator • Connect output grid of distance operator to input of reclass, specifying new output grid • Run again

7. Review of Simple Model • Benefits • Multiple logical steps encapsulated in a single step • Model Logic Recorded in Diagram • Model Parameters Recorded • Problems / Caveats • Default is not to show results… • Model as Created is 100% specific to particular data paths/locations on disk • Model Saving Bizarre.. • Default operation names make no sense to end users • Spatial Analyst Toolbar Options do *not* inherit

8. Showing Results • Simple, but not Obvious • Right Mouse on Output -> Add to Display • If at first you don’t succeed, try toggling again

9. Saving / Finding Models • By default, models saved in “My Toolboxes” folder • Main menu Tools->Options->My Toolboxes • Default is C:\Documents and Settings\(MIT Username) \Application Data\ESRI\ArcToolbox\My Toolboxes • Easiest to find in ArcCatalog/My Toolboxes • Can “Add Toolbox” stored on disk

10. Making Models Generalizable • Running Models • Can Double Click on Models in Toolbox Panel • By default, not too useful, because no user control of outputs • Generalizing Models • By default, models only use exact data originally specified • To make a model into a true “tool” need to specify which inputs / outputs are variable parameters • Right mouse on input or output • Select “Parameter” (toggle) • After Parameters are set, double clicking brings up user dialog

11. Making MB Diagrams Legible • All elements can be “renamed” from right mouse menu • Rename layers if necessary to clarify • Explain intent of geoprocessing operations • i.e. Isolate Residential Landuse instead of reclass1 • If Desired, change diagram properties • Square – Circle – Square • Box Background Colors • If you need better quality, export diagram…

12. Environment Variables in MB • Note • Spatial Analyst “Options” settings not inheritted • Must explicitly specify for MB • Two options • Can do once for all toolboxes (recommended) • RM Top Toolbox->Environment Settings • General Settings -> Extent • Raster Analysis Settings -> Cell Size • Can do once for each model

13. Model 2: Weighted Overlay • Goal: • To Create an Attractiveness Model with ability to “Weight” factors • Method: • Create separate ModelBuilder models for each factor • Nest models into master MB model • Combine with weighted overlay

14. Model 2 Implementation • Factor 1: Proximity to Residential • Factor 2: Proximity to Job Centers • Created by copying and pasting factor 1 model and adjusting inputs and outputs • Weighting • Factor 1 = 2X Factor 2 • Use Spatial Analyst Weighted Overlay tool

15. Weighted Overlay • Function • Takes any number of uniformly scaled input (factor) grids • Outputs the arithmetically-weighted average value at each grid cell • Equal weights – similar to addition plus rescale

16. NoData Treatment in Weighted Overlay • Any value averaged with NoData = NoData, • so must code “worst case” as some number • For attractiveness, this would be value “9” • Make sure that areas beyond maximum distance specified in distance operations is recoded to 9

17. Weighted Overlay “Restricted” Category • Important and useful! • Over-rides averaging behavior if any one factor is “too bad” (as you define it) • Restricted output value can’t be specified = (range) – 1 • In case of 1..9 evaluation, becomes a 0 • Thus requires further reclass to of 0 to 9 in order to maintain 1..9 range

18. Assignment for Monday 22nd • Implement your attractiveness model in ModelBuilder (revising as needed based on crit) • Build one submodel for each factor • Create one master model combining factors • Models should have elements renamed/formatted for review presentation • Export model diagram as JPEG image for Powerpoint • Resulting revised Powerpoint due to “Attractiveness Team” Monday 22nd 9am (or by negotiation with them)

19. Midreview Prep Nov 1 & 2nd

20. Midreview Schedule • Two Morning Sessions • Thursday November 1 • 9 – 9:45 Study Introduction, Visit & Base GIS Overview • 9:45 – 10:15 Accessibility Analysis for Albacete • 10:15 – 10:30 Coffee Break • 10:30 – 12 Presentation of Scenarios • Friday November 2 • 9 – 10:30 Presentation of Attractiveness Models • 10:30 – 10:45 Coffee Break • 10:45 – 11:30 Review of related PhD project work • 11:30 – 12 Summary with Reviewer Comments

21. Midreview Logistics • All students expected to present one topic • Could be Thurs or Friday • Logistics issue: sensible presentation dictates topic order, but some students can’t stay Thursday must present Friday • Therefore, will need some content swaps • Need one student team to “produce” each module (based on content generated in part by others)

22. Production/Presentation Teams • Intro / Study Visit / Base GIS Team • Accessibility Team • Scenario Team • Attractiveness Team

23. Team Assignment for Thursday 25th • Inventory already-produced materials in section • Outline module presentation order and presenters • Assign clean-up and production tasks as needed • Thursday will be “production day” • Review outlines with Stephen & I • Gather materials from others, or schedule handoffs for Friday, etc. • Produce base maps, explanatory introduction to section slides, etc.