Example 3 - Mapping address points on a thematic map
Other features illustrated: Viewing underlying records, clearing one dimension, changing universe from the spreadsheet
Background: If a dataset has address point information
that has been defined correctly, points can be mapped on top of a
thematic map from a separate dataset.
Goals: 1) Show the locations of all the public schools
in DC on top of a thematic map showing the median household income by
tracts from SF3. 2) Show how you can view the underlying records from
the spreadsheet to see all the information for the universe of the
- Create our underlying thematic map on which we will lay our school
locations. Open the Ferrett Session File (or saved data basket) named point_map_theme_sf3_median_income.fsf .
- Go to the Step 2 tab to see the variables in the data basket - median household income and tracts (all tracts in DC).
- "Make a Table"
- Drag the tract variable to column 1 to define the rows.
- Drag the income variable to C2, R1 and "Go Get Data".
- Highlight the data cells in column 2 and click on the "Map"
button in the toolbar. The map window showing the income by tract
opens. DO NOT CLOSE the map window.
- Go back to the spreadsheet window and CLOSE it.
- Go back to the Step 1 tab.
- Clear the data basket by clicking on the "Empty Data Basket" button on the right side.
- Open the Ferrett Session File (or saved data basket) named point_ccd_schools.fsf .
- Go to the Step 2 tab to see the variables in the data basket -
county (DC) and some information about the public schools, including
address, phone, number of students, teachers, and level of the school.
- "Make a Table"
- Drag the county variable to column 1 to define the rows.
- Drag the "MEMBER - Total students..." variable to C2, R1 and "Go Get Data".
- Highlight the C2,R3 data cell.
- Click on the "Point Map" button in the toolbar (US with a flag on it).
- After a few seconds, a dialog box appears asking if you want
to create a new map or add to an existing map. Select the "Add to
existing map" option and the theme map we created is shown and
highlighted. Click the "Ok" button.
Screenshot of the dialog box for adding point to a theme map:
- Find your map window in your taskbar and open it.
- In the map window's "View" menu, select "Layers", and then
from that select "Red Dot". The school location points will appear on
your map. These dots represent the schools for those students in the
selected table cell.
Screenshot of point map showing schools on median income theme in DC:
Additional Manipulations - Changing Universes in the Spreadsheet
- Back in your spreadsheet window, clear ONLY the column dimension -
go to the "Edit" menu, select "Clear", then select "All Columns".
- Drag the LEVEL variable into C2, R1 to re-define the columns, then "Go Get Data".
- Highlight the data cells in R3, C4 and C5, middle and high schools.
- Click on the "View Underlying Records" button in the toolbar
(looks like a spreadsheet with a magnifying glass on it). This brings
up a new window showing all the variables for the records with the
values highlighted. The output can be sorted by any variable column by
clicking in the header.
- Close the underlying record window.
- You can change your table to show some other set of counties.
- Clear your row dimension - "Edit" menu - "Clear" - "All Rows".
- Double click on the County variable in your spreadsheet
variable list on the right side. This will bring up the Geography
- Highlight "District of Columbia" shown on the right side and hit the "Delete" button.
- Highlight the FIPS county code on the left side and then hit the "Next" button.
- Highlight the FIPS state code on the left side and hit the "Next" button.
- Select "California" and hit the "Next" button. This moves California to the right side.
- Hit the "Next" button again. This will show all the counties in the state.
- Highlight the "Select All" at the top of the list and hit the "Next" button. This moves all counties to the right side.
- Hit the "Finish" button. You should be returned to your spreadsheet window.
- Drag the county variable to C1 to define the rows with all the counties in California. Hit the "Go Get Data" button.