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ASSIGNED in class Monday March 28

DUE: Decision on scale of data and maps Monday March 28

DUE: in class Wednesday April 20 (w/required discussion) at 9:00 am

Introduction:

This exercise involves making and interpreting choropleth maps of U.S. Census data in the area around your U.S. home.

You will draw upon past lecture material about data classification and color symbolization (in the Cartographic Abstraction Lecture Notes) to complete this exercise. You will also be expected to interpret the patterns you see on the maps you create, based on what you know about your home.

Basic Information about the U.S. Census

• Read about the general idea of a Census and the U.S. Census.

• U.S. Census Glossary

The U.S. Census provides data aggregated to many different sized areas, the smallest area being the block level - usually an area about the size of a city block. In rural areas these "blocks" are larger in area (but they contain about the same amount of people as a city block). Some, but not all Census data is available at the block level. Different data is available at the Census Block Group level (the data from numerous blocks are aggregated into a larger area). The following graphics illustrate the hierarchy of census geographic entities, and are taken from the U.S. Census Geographic Reference Manual which has much more information about U.S. Census Geography if you are interested (which of course you are).

You already used the U.S. Census Bureau's American Factfinder to locate some quick facts about your home county, in exercise 4. We will use some more advanced mapping features of this site to create detailed maps of 2000 U.S. Census data in your home neighborhood. Unfortunately, the Census has not yet managed to get the new 2010 Census data into this mapping system.

Goals: You will map eight different Census data variables, around your home, and provide basic map reading, analysis, and interpretation of patterns on these choropleth maps.

If the Census mapping site is not working it may be because you have your browser set to block pop-up windows. Turn that feature off for this exercise!

Go to the Thematic Maps page at the US Census Bureau.

You should see a map of the US by state with Persons Per Square Mile: 2000 data.

1) The American Factfinder site offers different ways to change scale. For now do this...

• from the list of links after You are here select Geography:

  

  
  

• A new page (as below) allows you to set the area you want the Factfinder to map.

• Please select County Subdivision (as below).

• Please set State, County, and Geographic Area to your home (the following shows selections for my home):

  

  
  

• Hit Show Result

• You should see a map of the area you just selected as below, which is of my 'home'. The map should have basic Geography (roads, boundaries, rivers, etc.) and should also have basic population data mapped out (the Thematic data) at a Census Tract level.

  

  
  

• If the area covered by the thematic data is not the area around your home, you need to repeat this step and select the correct Geography. You may need to select something other than county subdivision. If you are having trouble at this stage you must ask to your instructor for help.

2) Change the level of detail of the Census geography and data. From the pop-up menu near the top center of the page:

• ...select Block and you should see something like this: a map of the area around you home:
  

  
  

  Block level data is the most detailed. The patterns are similar to the patterns on the Census Tract but with more detail. Most of you will use Block level data for the rest of your exercise. If you are from a large city, you may have to use less detailed data, at the Block Group or Census Tract scale. If you are having difficulty at this state, please consult your kindly instructor.

  
  

To change scale (zoom in or out) select the + (zoom in) or - (zoom out) button and click on the map, or select a scale from the zoom bar on the left. This is zoomed in a bit from the map above:






The Census site has a limited number of scales, so you may not be able to get the perfect scale for your map. Don't zoom in too much: you want to be able to see the variation in the data you map around your home, not only the data in your home block.

To adjust the center of the map, use the hand tool.

To find out details about a particular block, select the i tool, which stands for identify and click on a particular block.

Please show the instructor your decision on the scale and detail (block level in most cases) of your map prior to proceeding with this exercise!

3) The American Factfinder site offers different ways to change data themes. For now do this...

• from the list of links after You are here select Theme:

  

  
  

• You will arrive at a page like the one below: a list of all Census 'Themes' you can map out:

  

  
  

• Review the list of Themes. There are many of them! Select one that seems interesting to you and then Show Result. I selected the Percent of Persons under 18 Years: 2000 and got this map:

  

  
  

• You will eventually select EIGHT different themes and, in essence, make a Census Atlas of Home using the American Factfinder site and the U.S. Census 2000 data. All of the maps should be the same scale. You may find that a map that is 7 miles across gives you a bit broader perspective on variations of Census social data around your home than a map that is 2.8 miles across. Keep in mind that the point here is to find geographic patterns, not to identify the specific details of the Census block your home is in.

  
  

4) Click once on the word Data Classes on the upper left side of the screen. A new smaller window should pop up.

You can adjust how the data is classified here. If you make changes, click Update to apply the changes to your map:






• Number of Classes: 5 is a good default, but you can select 2 to 7 classes.

• Color Scheme: select what you like best.

• Classing Method: Review the notes from class (in the Cartographic Abstraction Lecture Notes). Also, select Explain Classing Methods on the pop-up page for on-line information. Briefly:
  • Natural Breaks: best default: statistically determines natural 'gaps' in the data and places the class divisions at those places.

  • Equal Interval: Same numeric interval for each class.

  • Quantile: equal number of data values in each class.

    
    

You can also adjust which features are mapped by selecting the Features tab and checking the features you want displayed. If you make changes, click Update to apply the changes to your map:






Finally, the Title tab allows you to change the title of the map if you so choose.

5) Generate 8 different maps of 8 Census themes for your Census Atlas of Home. Each should have the same scale and US Census data level (eg., Blocks) and each should have the same features (roads, rivers, etc.)

• Save each map and associated legend. The map won't make sense without the legend. You can save the map and legend separately and insert them in your exercise, or use a screen capture that includes both in one image.

6) Finally: do some basic map reading, analysis, and interpretation for each map. This should be easy for most of you to do as you are familiar with the place - home - you have mapped.

Format your work like the following example (you should be able to fit each map with its associated reading, analysis, and interpretation on one page):

Map reading: process of determining what the map maker has depicted

ex) A choropleth map of the city of Waukesha, Wisconsin, showing the Percent of Persons under 18 years old, in 5 classes, classified by natural breaks.

Map analysis: process of seeing spatial patterns on the map

ex) In general, the further you move away from downtown Waukesha, the higher the percent of people under 18. Distinct low areas in the north-central part of town, and in a few blocks in the extreme south part of town, and directly south of downtown. Distinct high areas in the west, south-east, and north-east areas away from downtown. Mid-level areas in many of the areas surrounding downtown. The particular block where my parents live has a mid-level of persons under 18 years old.

Map interpretation: explaining the patterns noticed in the map analysis; note low areas, medium areas, and high areas; note things that surprised you and explain patterns based on what you know about your home.

ex) These patterns are explained in several ways. The general pattern of a higher percentage of people over 18 living in the areas away from downtown is easy to explain: more families with children live in the suburban areas of town, than live downtown. Specific very low blocks are areas that are not residential: some low blocks downtown are largely commercial and have few houses or apartments; some low blocks to the south of town are industrial parks, again with few places for anyone to live (looking at a map of general population in the area shows that few people live in these areas). High areas are explained by several factors: some are new subdivisions, which appeal to families with children. Also, the Census blocks around the three high schools in town have higher percentages of people under 18 - people with kids live near schools. I was surprised that there were relatively low numbers of under 18 persons in many of the older residential areas of Waukesha. This is probably because many of the homes in these areas - built in the 1960s - are owned by couples who's children, like myself, no longer live at home: empty nesters. It may be the case that these folks will sell their homes to young couples before the next Census, and these areas will show higher percentages of people under 18 in the 2010 Census as a result.

What is Due

Please turn in the following:

• Eight maps of eight U.S. Census Variables each with a legend

• each map should have a paragraph of map reading, a paragraph of map analysis, and a paragraph of map interpretation (3 paragraphs total; the reading and analysis paragraphs can be briefer and the interpretation paragraph should be a bit longer).

• Go to the Census Bureau's Quick Facts page for your home state and county, and check out the population change since the 2000 census. If there is a significant change, your 2000 maps (the only data available on the Census mapping site) may be not so reliable. If the change is low, then your maps may still be relevant. Review the Quick Facts for your county and discuss, in a paragraph, if you think the now 10 year old data you are mapping has much relevance, based on what you know of your place.
  • on the U.S. Census main page, select your state from the "Find an Area Profile with Quick Facts" pop up menu. Select your county or city from that page.

Remember that we will take some class time to discuss the results of this exercise on the day it is due. You will use these maps in your take home final exam.

E-mail: jbkrygier@owu.edu

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