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Grid-based Map Analysis and GIS Modeling Understanding Spatial Patterns and Relationships Berry & Associates // Spatial Information Systems 2000 S. College.

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Presentation on theme: "Grid-based Map Analysis and GIS Modeling Understanding Spatial Patterns and Relationships Berry & Associates // Spatial Information Systems 2000 S. College."— Presentation transcript:

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2 Grid-based Map Analysis and GIS Modeling Understanding Spatial Patterns and Relationships Berry & Associates // Spatial Information Systems 2000 S. College Ave, Suite 300, Fort Collins, CO Phone: (970) …visit our Website at “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” Intermediate Workshop Presented by Joseph K. Berry 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

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

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

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

6 Manual GIS (Geo-query circa 1950) 3) Pass a long Needle through the stack of cards and lift… 4) Repeat using the search results sub-set for more characteristics Cards pulled up… Hole … DO NOT have characteristic #57 Cards falling down… … HAVE characteristic Notch Timber Stand Map (wall) Spatial Table (spatial objects) Where Data Table (attribute records) What Query Tray holds all of the index cards for a project area 1) Index Card with series of numbered holes around the edge and written description/data in the center 5) Card ID# identifies the timber stand polygons from the search and the appropriate locations are shaded— …a “Database-entry Geo-query” …a “Database-entry Geo-query” #57 Hole Index card (tray) ) Special Punch was used to notch-out the hole assigned to a particular characteristic (attribute), such as #11 notch = Douglas fir timber type Notch# (Berry)

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

8 Elevation Surface (Berry) Calculating Slope and Flow (Map Analysis) Inclination of a fitted plane to a location and its eight surrounding elevation values Total number of the steepest downhill paths flowing into each location Flow (28,46) = 451 Paths Flow map draped on Elevation Flow map (Berry) Slope (47,64) = 33.23% Slope map draped on Elevation Slope map %

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

10 Erosion_potential Streams Erosion Buffers Distance 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” Calculating Effective Distance (variable-width buffers) Effective Buffers (digital slide show VBuff2) VBuff2 Effective Erosion Distance CloseFar Heavy/Steep (far from stream) Light/Gentle (close) Simple Buffer (Berry)

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

12 Basic Grid Structure …the Analysis Frame provides consistent “parceling” needed for map analysis and extends Points, Lines and Areas to Surfaces …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 Fill Layer Mesh Grid Map (Berry)

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

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

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

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

17 Homeowners EnvironmentalistsEngineers HD & VE times 10 RP & SA times 10 HD & RP times 10 Start End EngineersEnvironmentalistsHomeowners IndividualSolutions Housing Density Road Proximity Sensitive Areas Visual Exposure MostPreferredLeastPreferred Routing Criteria Model Accuracy/Precision (spatial modeling perspective) CalibrateExpertOpinion …cognitive mapping has no definitive right/wrongsolution—MostPreferred WeightStakeholderValues CombinedSolution Start End Average of the three cost surfaces Optimal Path Optimal Corridor (Berry)

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


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