Instructor Notes W4d1

On Sharing Your Work

Google Drive:

  1. Create a folder for your soc128 stuff.
  2. Create a subfolder for the stuff you want to share with me.
  3. The subfolder should be called YOURNAME-SOC128-SHARE.
  4. When you put things in the subfolder you should name them like this (the nn starts with 01 and goes up as you have multiple files on same date/project)
    • surname-YYYYMMDD-nn-assignmentDescription

List of Stumbling Blocks and Headaches (so we can go over in lab)

Theory of Joins and Thematic Mapping

  1. Geometry with IDs + Data with IDs + visual encoding = geographic data visualization
  2. Two steps: join the data, symbolize the data

Joining the Data

Standard One-to-One "Join by Name"

join maplayer01 and table02 where maplayer01.ID=table02.StateID

FeatureID Name ID ~geospatial data
001 California 006 23.201,24.009,94.009,94.000039,….
002 Nevada 015 blah blah blah,….
003 Oregon 018 blah blah blah,….
StateID Population LandArea
015 2,750,000 110,000
018 3,900,000 98,000
006 38,000,000 164,000

JOIN creates new columns in the geo-layer table.

What happens if there is missing data (geometry with no matching data)?

What happens if there is extra data (data with no matching geometry)?

Thematic Mapping

Would it make sense to try to visualize the land area of these three states?

Computing a Column