Appendix 14 GIS Analysis Concepts

1

• Some ideas for students to think about while
  doing class evaluation
•  
• Goals of the course
•  
• To teach anyone who wants to learn GIS, GIS. It
  is an intro course, so it tries to serve all
  knowledge levels.
•  
• Trying to have you leave here with a solid
  grounding of GIS and GIS science fundamentals. I
  have the exam later in the semester because I
  think it is important for your learning to go
  back and think about the early class lecture
  content with some experience using GIS.
•  
• I teach using the hands on labs for two reasons.
  It allows me to show you how to do important GIS
  steps, but it also serves as a reference book for
  later. I know of NO book that provides you the
  steps I do in the coursepack.
•  
•        
• Questions
•  
• Are the computer hands on classes too tedious?
• Would it be better to provide less structured or
  hand-holding classes? I know other classes try to
  do it this way, but I think for an introductory
  class this is a better way. If/when I teach an
  advanced course I am thinking that will be more
  free-form and open ended. But would like your
  opinion.
• Should I move to a two-exam system? With one
  earlier in the semester? Will that take away from
  the idea that I think you learn rethinking the
  intro lectures after some time with doing GIS
  stuff?
•  
• Should I cut down the GIS input section of the
  class, and maybe not show address geocoding to
  give more time for the analysis stuff at the end?

2
Analysis 1 ClassAttribute and Select by
Location Queries (p. 230 Bolstad)

• Select queries on the layers attribute table
• ArcMap selection menu, select by attribute
  queries
• Neighborhood analysis (queries)
• Whats adjacent?
• (In ArcMap selection menu, select by location
  queries)
• Whats nearby?
• (In ArcMap selection menu, select by location
  queries)
• Well do some exercises of this after this
  lecture

3
ANALYSIS 2 What kinds of analysis can we do with
GIS?

• Measurements
• Layer statistics
• Queries
• Buffering (vector) Proximity (raster)
• Filtering (raster)
• Map overlay (layer on layer selections)
• Transformations
• Reclassification

4
Buffer zones around (a) point, (b) line, and (c)
area features
4a. Buffering Vector (p. 245 Bolstad)

• Buffer at a specified distance At a distance
  from an attribute fieldand As multiple rings at
  a defined increment.
• In ArcMap ArcToolbox, Analysis tools,
  Proximity, Buffer wizard

5
7. Transformations

• Functions to transform a layer of one feature
  type to another. Some examples
• Point to line interpolation (contour mapping)
  (Bolstad ch. 13)
• Point to polygon buffering
• Polygon to polygon dissolve/merge (p. 243
  Bolstad)
• Raster to vector conversion
• (In ArcMap, 3-D analyst extension, convert,
  raster to feature)
• Vector to raster conversion
• (In ArcMap, 3-D analyst extension)
• Raster to Triangular Irregular Network (TIN)
• In ArcGIS, 3-D analyst extension
• Resampling a raster grid convert one cell size
  to another cell size

6
Vector overlays (a) point-in-polygon
6a. Vector Overlay Point-in-Polygon (p. 256
Bolstad)

• Point-in-Polygon is used to find out the polygon
  in which a pointfalls.
• Example Which landcover does each
  meteorological station fall into?
• Bolstad notes a problem going the other way
  polygon to point.
• Anyone remember?

7
Vector overlays (b) line-in-polygon
6b. Vector Overlay Line-in-Polygon

• Line-in-Polygon Used to find out what polygons
  a line falls within.
• More complicated than point, because one line
  can be in more than onepolygon
• Example Which roads pass through forest areas?
  What parcels might be affected by a new bike
  trail design?

8
Vector overlays (c) polygon-on-polygon
Where are areas of forestry OR areas within the
resort?
6c.Vector OverlaysPolygon onPolygon(Bolstad
p. 261)
Where is the resort boundary and where is there
forest within the resort?
Also called clipping
Where is there forest within the resort?
Note Problem of sliver polygons when
boundaries dont coincide exactly
9
6d. Vector Overlay In ArcMap

• ArcToolbox/Geoprocessing
• Available Functions
• Union see slide 6c. Atbox-An
  Tools-Overlay-Union
• Intersect see slide 6c. Atbox-An
  Tools-Overlay-Intersect
• Clip (cookie cutting) see slide 6c. Atbox-An
  Tools-Clip
• Merge appends two or more layers together to
  create a new layer (e.g., side by side).
  Atbox-Data Management Tools-General-Append
• Dissolve reduces number of features by merging
  adjacent features with the same attribute value.
  Creates a new layer. Atbox-Data Management
  Tools-Generalization-Dissolve