California's Japanese Americans

The impact of internment on California's Japanese American population was obviously enormous, but it went well beyond the three to four years spent in the assembly centers and relocation camps. Based on available census data from 1930, 1940, and from1950, after the war and after the camps were closed, you can begin to see the broader impact of the internment experience in terms of the dramatic shift in popuation.

An Example to Get You Started -

In order to assess the impact of the internment on California’s Japanese population let's go back to the decade of the 1930s and and compare and contrast the changes in both California's Japanese American population and changes in the population of the state as a whole.

Load your GIS and open the Japanese Internment project file. Zoom in on California. You are going to determine the percent change of the Japanese American population from 1930 to 1940 for each of the counties in California and present this information in a data map.

Look first at the list of census categories in the California's Japanese Americans worksheet. Notice that the percentage you want is not on the list. You need to do some simple arithmetic, dividing the Japanese40 population by the Japanese30 population to obtain the desired percentage.

My World
ArcGIS
• Click on the Analyze tab, select to Add Field(s) By Math Operation, and complete the form as follows:

• When you click OK the computation you want is done and the data shown in Visualize mode.

• Next, click the Edit Appearance button ().

You can choose the Colorscheme you want to use. Enter 7 as the Number of Fill Colors and select to Classify By: Quantiles. This will give you seven groups with approximately the same number of counties per group.

• Click on the Apply button and Close the window.

 • Right click the California layer in the table of contents and select Properties....

• Click on the Symbology tab and select Quantities.

• In the Fields pane select Japanese1940 as the Value and Japanese1930 as the Normalization value.

The result is the is the desired division. It is said to be a normalized value because we now have a rate that is not affected by the size of the counties.

• In the Classification pane click the Classify button. You will see a new window. Select to classify by Quantiles and 7 classes as pictured below:

This will give you seven groups with approximately the same number of counties per group.

• Click OK

• You can define your own labels to make the map easier to read by editing the values in the Labels column:

• Click OK again to leave the Properties window.


Once the data is available it is easy to prepare a map of the results like the one below.


My World
ArcGIS
• Select File >> Layout & Print from the main menu.

• Uncheck the Show Scale and Show Compass boxes in this case.

• Click Print

• My World prints an image of the map to a file. Name the file and Save it where you can get to it from your word processer.

 • Select View >> Layout View from the main menu.

• A map template is provided for you to edit. Double click on:

- Map Title to enter your own title
- Created by to add your name and today's date

• Zoom in () and/or pan () to position the map image as desired.

• Select File >> Print from the main menu. Check to see that the correct printer is selected and that the orientation of the map is correct.

• Click OK to print your map.

• Select View >> Data View from the main menu.


Your turn. Prepare a similar map showing the change in the state's total population from 1930 to 1940. You need to go through the same steps except that this time you need to define the same classification scheme as in the previous map. This will allow you to examine the results on a comparable county-by-county basis.

My World
ArcGIS
• Click on the Analyze tab and set up the division to create the new percentage as you did for the Japanese population data.

• Click on the California layer to make it the active layer. Scroll to select the % Change in Japanese Population 1930-1940 field as pictured below:

• Click on the Edit Appearance icon ( ) and select to Copy... to the new % Change in Total Population field.

• Click Copy.

• Click Close.

 • Right click the California layer in the table of contents and select Properties....

• Click on the Symbology tab and select Quantities.

• Set up the Value and Normalization fields as before this time using the TOTALPOP40 and TOTALPOP30 fields.

• Copy the Range and Label values from the first map to allow you to compare county-to-county on the same terms.

• Click OK


Compare your maps side-by-side.

To Start You Thinking -

1) Which California counties had no Japanese American population in 1930?

2) Which counties had the most significant growth in Japanese American population in the decade of the 1930s? (This is a trick question. You will need to examine not only the finished map, but individual counties as well. For example, according to the map, in Lake County, north and east of the San Francisco area, it looks like the increase has been substantial. Click on the county with the information tool, though, and examine the actual Japanese American populations in 1930 and 1940.)

3) Generally speaking, how does the change in the Japanese American population compare with the change in the population of the state as a whole during the decade of the 1930s? What factors in California state history during the 1920s and 30s might account for the differences in change in the populations?

Last modified in July, 2008 by Rick Thomas