1. Spatial Analysis – vector data analysis
Lecture 2

2. Recap: three data models
Vector
Raster
Geodatabase (object-oriented data model)
Vector data and table
feature class is the basis
Raster data
The real world is complex. Neither discrete (object) nor continuous (field) can perfectly represent some of real world situations. We need combined model: dual, hybrid, or object-oriented approach

3. Spatial Analysis tools in ArcToolBox
Vector data analysis:
Shapefile &
Feature class/table
Raster data analysis

4. Details
Vector

5. 1. Extract
To create a new subset from the input (shapefile, features and attributes in a feature class or table) based on spatial intersection or an attribute query.
Clip
Select
Split
Table select

6. Clip Learn more from help XY tolerance:
The minimum distance separating all feature coordinates (nodes and vertices) as well as the distance a coordinate can move in X or Y (or both). You can set the value to be higher for data that has less coordinate accuracy and lower for datasets with extremely high accuracy.
Learn more from help

9. Select

10. Split

11. Table select

12. 2. Overlay
Joining two existing sets of features into a single set of features to identify spatial relationships between the input features.
Erase
Identify
Intersect
Spatial Join
Symmetrical difference
Union
Update

20. 3. Proximity
Identify features that are closest to one another, calculate the distances around them, and calculate distances between them.
Buffer
Create Thiessen Polygon
Generate Near Table
Multiple ring buffer
Near
Point distance

23. Not dissolved
Dissolved

24. Example

26. How to form Thiessen polygons
Also known as 'Voronoi networks' and 'Delaunay triangulations', Thiessen polygons were independently discovered in several fields of study, including climatology and geography. They are named after a climatologist who used them to perform a transformation from point climate stations to watersheds.
Thiessen polygons can be used to describe the area of influence of a point in a set of points. If you take a set of points and connect each point to its nearest neighbor, you have what's called a triangulated irregular network (TIN). If you bisect each connecting line segment perpendicularly and create closed polygons with the perpendicular bisectors, the result will be a set of Thiessen polygons. The area contained in each polygon is closer to the point on which the polygon is based than to any other point in the dataset.

29. Statistics Basic statistic to the attribute table Frequency
Summary statistics