SRC Software for 2000 Census Data; Summary File 1 DVD, part 2

SRC Software for 2000 Census Data
Summary File 1 DVD
Part 2

Custom Variables | Saving Custom Variables | Custom Radii

Last updated on January 8, 2002

Custom Variables

The Custom Variables section of the software allows you to do simple mathematical operations and create percentages. If you are familiar with spreadsheet programs, you may prefer to download the raw data and perform those operations with a spreadsheet program rather than the DVD software.

In the Simple Variables example, we had already chosen block groups for the City of Detroit.

Because we had already chosen our geography, we pressed the top tab to return to Output and saved the file with a new name, detage.csv rather than detrbg.csv. This preserves the spreadsheet in our first file.

This time we chose the Custom Variables tab rather than the Simple Variables tab. Because we had not exited the program beforehand, the program remembers the last search. We decided to keep the Geographic Identifiers in the table. To delete the previous tables, highlight them and PRESS DELETE.

Create a separate variable for all of the 15-21 year olds (male and female).

Identify the table you want by browsing the P tables in the lefthand box. (The PCT tables are limited to the tract level; we want block groups.) The appropriate table is P012.
Click on the + next to P012 to expand it.
Highlight P012006, click on the VAR button above the formula box, then click on the + button above the formula box. The first part of your formula should appear in the box.
The cursor will move down to P012007 automatically. Repeat the process through P012009.
Move the highlight from P012010 and place it on P012030. Continue the selection.
Highlight the last variable, P012033. Click on the VAR button above the formula box. Do NOT click on the plus.
Move your cursur to the NEW VARIABLE NAME box and name your variable. Then click SELECT. Your new variable should appear in the box at the right.

New variable in righthand box.
To obtain a spreadsheet, click on FINISH.

Use the new Custom Variable created to determine the percentage of the total population aged 15-21.

Double-click on the name of the new custom variable in the righthand box to place it in the formula box. When you do so, your named variable reverts to the original formula.
Place your cursor in the formula box and TYPE parentheses (not brackets) around the formula.
Click on the slash (/) operator.
Page up to the list of variables on the lefthand side of the screen. Expand P1. Highlight P001001 and then click on the variable box above the formula box.
Click on the asterisk (*) operator. Type 100 after the asterisk. This will change your formula into a percentage.
Place your cursor in the New Variable Name box. Backspace over the old name. Type in a name for the newly-created variable.
Click on SELECT to transfer your new formula to the righthand box.

Once your new formula is the righthand box, click on FINISH to obtain the data.

The resulting spreadsheet is shown below. The columns were widened by highlighting the second and third rows, then using the FORMAT/COLUMN/AUTO FIT option.

The column named 1521per is already a percentage. You can change the number of decimal places in a percentage by first highlighting the entire column, then FORMAT/CELLS/NUMBER/ and changing the number of decimal places.

Saving Custom Variables

Although you cannot save a custom variable by inserting it in your variable tree (lefthand side of the screen), you can save it by saving your workspace.

When you close your program, you will be asked if you want to write over your old workspace or name a new one. Unless you are sure, it is a good idea to name a new workspace. In this case, we would not overwrite detrbg.aws; we would rename it detage.aws

The next time you log on, you will be asked if you want to open an old workspace. If you open detage.aws, you automatically have the same geography and custom variables you used before. If you change either the geography or custom variables in your second use, you should probably rename the workspace when you exit.

Custom Radii

The software allows users to create and save their own custom radii using land measurement or driving time. The resulting table will give a total for the area chosen but will not include data for individual parts of that area, such as individual blocks within a three-mile radius.

A custom radius requires an internal latitude or longitude. The "radius within address" feature does not work. The easiest way to obtain the latitude or longitude is by using the American Factfinder (http://factfinder.census.gov) web site. Go to DATA SETS/SUMMARY FILE 1/DETAILED TABLES. First choose your geography; then choose Table P1 for total population. When the screen displays the resulting table, CLICK on the OPTIONS/SHOW GEOGRAPHIC IDENTIFIERS BUTTON. The latitude and longitude is toward the bottom of the identifiers screen.

You can also determine the latitude and longitude using the Census DVD.

1. Use PICK GEOGRAPHY to choose the physical area (county, city, tract, block group, block) that you want.

2. Choose OPTIONS. Change from REPORT to FILE. SAVE AS and name the file anything you want. This is a temporary file.

3. Pick SIMPLE VARIABLES. Expand GEOGRAPHIC IDENTIFIERS.

4. Highlight Internal Latitude and Select. Highlight Internal Longitude and Select. These two identifiers should appear in the righthand column. Then PRESS FINISH.

5. Display your spreadsheet and print or write down the latitude and longitude.

6. Go back to PICK GEOGRAPHY. Highlight CUSTOM RADII. Click on FILE. Click on ADD RADII.

7. The FROM AN ADDRESS feature does not work with SF1 in the pop-up CREATE A POINT MENU. Type in the latitude and longitude; then PRESS OK.

8. In the COMPLETE A POINT MENU, you can create your own circles. You can change miles to kilometers or driving time. PRESS OK.

9. Choose your variables, either simple or custom. In this case, we've used and previous custom variable so we just pressed FINISH. You can see from the spreadsheet, that approximately 10% of Detroit's population is aged 15-21. That percentage slowly diminishes the farther you move away from the city. It is also possible that the 30 mile radius extends into another city.

10. You save your custom variables by saving your workspace with a new name. The next time you log into that workspace and PICK GEOGRAPHY, you must expand the custom radius box and check off the latitude/longitude before using it.

Grace York, Coordinator, Documents Center
University of Michigan Library
January 8, 2002
Send comments and suggestions to graceyor@umich.edu

http://www.lib.umich.edu/govdocs/census2/alloca4b.htm

January 7, 2002 this page has been accessed