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Where have we come so far?

Where have we come so far?. By now, you should be familiar with: What GIS is How GIS works Some of what GIS can do GIS data formats Spatial data Tabular data Modifying display of data. What comes next?. S p a t i a l A n a l y s i s. Basic vector analysis. Examples:

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Where have we come so far?

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  1. Where have we come so far? • By now, you should be familiar with: • What GIS is • How GIS works • Some of what GIS can do • GIS data formats • Spatial data • Tabular data • Modifying display of data

  2. What comes next? S p a t i a l A n a l y s i s

  3. Basic vector analysis • Examples: • Which forest stands lie within 100 m of a road? • Which sampling plots have been covered by a recent slope failure? • Does any stream pass through the oldest stands in a forested area?…

  4. Overview of basic vector analysis • Analyzing spatial relationships is done with: • Layer-on-layer selection • Spatial join • Other spatial relationships will be investigated in the next lesson.

  5. Analyzing spatial relationships • Relationships between features • Proximity • Containment • Overlap • All based on feature geometry

  6. Overview of basic vector analysis • Layer-on-layer selection • Selecting points near a line (proximity) • Selecting adjacent features (proximity) • Line-on-polygon selection (containment) • Polygon-on-line selection (overlap) • Point-in-polygon selection (containment) • Polygon-on-point selection (overlap) • Polygon-on-polygon selection (overlap)

  7. Layer-on-layer selection • Selecting points near a line (proximity)

  8. Layer-on-layer selection • Selecting adjacent features (proximity)

  9. Layer-on-layer selection • Selecting adjacent features (proximity)

  10. Layer-on-layer selection • Line-on-polygon selection (containment)

  11. Layer-on-layer selection • Polygon-on-line selection (overlap)

  12. Layer-on-layer selection • Point-in-polygon selection (containment)

  13. Layer-on-layer selection • Polygon-on-point selection (overlap)

  14. Layer-on-layer selection • Polygon-on-polygon selection (overlap)

  15. target layer selector layer Layer-on-layer selection • Definitions • Target layer: the layer we want to know something about • Selector layer: the layer we are spatially referencing to • For a series of streams, find the distance to the nearest forest stand

  16. Layer-on-layer selection: feature type relationships • Spatial relationships follow geometric rules

  17. target layer selector layer Selecting points near a line (proximity) • Find inventory plots near streams

  18. Selecting adjacent features (proximity of 0) • Find stands adjacent to other stands

  19. Line-on-polygon selection (intersection, proximity of 0, overlap) • Streams within stands

  20. Polygon-on-line selection (intersection, proximity of 0, overlap) • Stands traversed by roads

  21. Point-in-polygon selection (containment) • CFI plots within moderate to high windthrow potential soils

  22. CFI plots within moderate to high windthrow potential soils

  23. Overview of basic vector analysis • Spatial join • Spatial join: containment • Spatial join: proximity

  24. Spatial join • Layers are joined based on geometry • Features are related and compared for distance and containment • Based on feature geometry

  25. Spatial join • Layers are joined based on geometry

  26. Spatial join • Layers are joined based on geometry

  27. Spatial join: containment • Records are joined for features within other features • Polygon attributes are attached to points • related fields can be used for display

  28. Spatial join: proximity • Appends tables and automatically adds distance field distance from each plot center pointto the closest road line distance used asdisplay field

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