Gridbased Map Analysis and GIS Modeling Understanding Spatial

Grid-based Map Analysis and GIS Modeling Understanding Spatial Patterns and Relationships Intermediate Workshop Presented by Joseph K. Berry “Map Analysis and GIS Modeling is technical Oz …you’re hit with a tornado of new concepts, then come back to yourself a short time later wondering what on earth all those crazy things meant” Part 1 – Introduction and Data Considerations Part 2 – Spatial Analysis Techniques and Considerations Part 3 – Spatial Statistics Techniques and Considerations Part 4 – GIS Modeling Approaches and Considerations Berry & Associates // Spatial Information Systems 2000 S. College Ave, Suite 300, Fort Collins, CO 80525 Phone: (970) 215 -0825 Email: jberry@innovativegis. com …visit our Website at www. innovativegis. com/basis

(Nanotechnology) Geotechnology (Biotechnology) Geotechnology is one of the three "mega technologies" for the 21 st century and promises to forever change how we conceptualize, utilize and visualize spatial information in research, education and commercial applications Geographic Information Systems Remote Sensing Global Positioning System GPS/GIS/RS Today’s Focus Where Mapping involves precise placement (delineation) of physical features (graphical) Descriptive Mapping is What Prescriptive Modeling Why and So What Analysis involves investigation of spatial relationships (numerical) (Berry)

Historical Setting and GIS Evolution Manual Mapping for 8, 000 years GIS = Geographic Information Systems …a more recent expression of mapping (40 years) Computer Mapping automates the cartographic process (70 s) (digital slide show World. Zoom) Spatial Database Management links computer mapping techniques with traditional (digital slide show Real. Estate) database capabilities (80 s) Real. Estate) Map Analysis representation of relationships within and among mapped data (90 s) …the focus of today’s workshop Multimedia Mapping full integration of GIS, Internet and visualization technologies (00 s) …but that’s another story (Berry)

Desktop Mapping Framework (Vector, Discrete) Click on… Select Theme Zoom Pan Info Tool Theme Table Distance Spatial Table Geo-Query… Query Builder : Object ID X, Y : …identify tall aspen stands Attribute Table Feature : Object ID : Species : Aw : etc. Big …over 400, 000 m 2 (40 ha)? Discrete, irregular map features (objects) (Berry)

Manual GIS (Geo-query circa 1950) 1) and written description/data in the center Hole Notch 15 14 #11 13 12 9 8 Index Card with series of numbered holes around the edge 10 2) Spatial Table Special Punch was used to notch-out the hole assigned to a particular characteristic (attribute), such as #11 notch = Douglas fir timber type 3) 7 (spatial objects) Where Pass a long Needle through the stack of cards and lift… Hole 6 Cards pulled up… 5 … DO NOT have characteristic 4 (tr ay ) 3 Query Tray holds all of the index In de x 1 ca rd 2 cards for a project area 7 #5 Notch Data Table Cards falling down… 7 … HAVE characteristic #5 Repeat using the search results sub-set for more characteristics 5) Card ID# identifies the timber stand polygons from the search and the appropriate locations are shaded— …a “Database-entry Geo-query” M ap 4) Ti m be r. S ta nd What (w al l) (attribute records) (Berry)

MAP Analysis Framework (Raster, Continuous) (Short Exercise #1) Click on… Zoom Pan Rotate Display Shading Manager Grid Analytics… Map Analysis …calculate a slope map and drape on the elevation surface Grid Table : --, --, --, --, 2438, --, --, --, : Continuous, regular grid cells (objects) Points, Lines, Polygons and Surfaces (Berry)

Calculating Slope and Flow (Map Analysis) Inclination of a fitted plane to a location and its eight surrounding elevation values Slope (47, 64) = 33. 23% % Slope map draped on Elevation Slope map Elevation Surface Flow (28, 46) = 451 Paths Total number of the steepest downhill paths flowing into each location (Berry) Flow map draped on Elevation Flow map (Berry)

Deriving Erosion Potential & Buffers Slope_classes Reclassify Flow/Slope Erosion_potential Reclassify Slopemap Overlay Reclassify Erosion Potential Flowmap Flow_classes Protective Buffers But all buffer-feet are not the same… …reach farther in areas of high erosion potential (slope/flow Erosion_potential) Streams Simple Buffer Erosion_potential Simple Buffer (Berry)

Calculating Effective Distance (variable-width buffers) Distance Erosion_potential Distance away from the streams is a function of the erosion potential (Flow/Slope Class) with intervening heavy flow and steep slopes computed as effectively closer than simple distance— “as the crow walks” Effective Erosion Distance Erosion Buffers Close Streams Far Simple Buffer Heavy/Steep (far from stream) Light/Gentle (close) Effective Buffers (digital slide show VBuff 2) (Berry)

Erosion Potential Buffer Model (Map. Calc script) Simple erosion potential model– based on terrain slope and flow (Short Exercise #2) Workshop CD Bighorn_erosion. scr Script See Default. htm …extended to derive a Variable-width Buffer (Full Exercise #2) (Berry)

Basic Grid Structure …a Grid Map consists of a matrix of numbers with a value indicating the characteristic or condition at each grid cell location—geo-registered set of Grid Layers Lines Layer Mesh Grid Map Fill …the Analysis Frame provides consistent “parceling” needed for map analysis and extends Points, Lines and Areas to Surfaces (Berry)

Recognizing Data & Display Types Data Types Numerical Distribution — • Nominal, Ordinal (Qualitative) • Interval, Ratio (Quantitative) • Binary (Boolean) Geographical Distribution — • Choropleth (Discrete) • Isopleth (Continuous) Display Types Display Form — 2 D or 3 D Display Structure — Grid or Lattice Display Data Type — Discrete or Continuous (Berry)

Vector to/from Raster V to R– burning the points, lines and areas into the grid (fat, thin and split) Points— Containing Cell Lines Polygons Points— Cell Centroid R to V– connecting grid centroids, sides and edges (line smoothing) Old saying—“…raster is faster, but vector is corrector” Vector— “precise” placement of spatial objects Grid— “accurate” characterization of spatial relationships (Berry)

Accuracy versus Precision The Wikipedia defines Accuracy as “the degree of veracity” (exactness) while Precision as “the degree of reproducibility” (repeatable) Accuracy describes the closeness of arrows to the bull’s-eye at the target center (actual/correct) High Accuracy but Low Precision Handheld GPS unit Accuracy vs. Precision …the “target analogy” compares measurements to the pattern of arrows shot at a target High Precision but Low Accuracy Precision GPS unit Precision relates to the size of the cluster of arrows— grouped tightly together is considered precise (Berry)

Classification versus Delineation (spatial perspective) Interpreter A Interpreter B Interpreter C Superimposed interpretation boundaries Vegetation Parcel Mapping Accuracy = classification (What) Photo Interpreter A Cottonwood Precision = delineation (Where) Photo Interpreter B Ponderosa Pine Photo Interpreter C Cottonwood Classification Accuracy (What) Delineation Precision (Where) (Berry)

Model Accuracy/Precision (spatial modeling perspective) Routing Criteria Most Preferred 1 2 Calibrate Expert Opinion Least Preferred 3 4 5 6 7 8 HD & VE times 10 Homeowners 9 Housing Density Road Proximity RP & SA times 10 Sensitive Areas Visual Exposure HD & RP times 10 Environmentalists …cognitive mapping has no definitive right/wrong solution— Engineers Weight Stakeholder Values Most Preferred Start Optimal Path Optimal Corridor Engineers Environmentalists Average of the three cost surfaces Homeowners Individual Solutions Start End Combined Solution End (Berry)

…but before we leave Introduction & Data Considerations to tackle Spatial Analysis (operations for reclassify, overlay, distance and neighbors), any… Questions? (Berry)