Instructor Notes W4d1
On Sharing Your Work
Google Drive:
- Create a folder for your soc128 stuff.
- Create a subfolder for the stuff you want to share with me.
- The subfolder should be called YOURNAME-SOC128-SHARE.
- 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
- Geometry with IDs + Data with IDs + visual encoding = geographic data visualization
- 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
25
39.8
231.7