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?

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 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 target layer selector layer

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

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

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

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 point to the closest road line distance used as display field