Geography 417
Mapping Exercise 1: Population, Land Cover and Agricultural Development in California
In this exercise, you will use an on-line mapping tool called DDViewer to examine patterns of land cover in California. The objectives of this exercise include:
1) The student will produce maps of California using an on-line software program.
2) The student will interpret data and cartographic representations of the data.
3) The student will distinguish between two major strategies for classifying mapped data.
4) The student will be able to describe and analyze regional patterns of population, landcover and agriculture.
5) The student will recognize natural and man-made landcover regions and patterns in California.
6) The student will formulate hypotheses regarding natural landcover and agricultural potential/output.
7) The student will answer questions correctly on the test regarding concepts and terms in bold presented below.
Background: California is the nation’s leading agricultural producer. Agriculture may be considered the states’ number one economic activity, yet few urban students know much about our agricultural economy or how environmental and man-made conditions permit the enormous agricultural bounty in the state.
Instructions:
1) Fill in your name (first name first) and email in the response boxes below.
USE THE TAB BUTTON OR MOUSE TO MOVE CURSOR BETWEEN RESPONSE BOXES. IF YOU PRESS ENTER, THE FORM WILL SUBMIT AND YOU’LL HAVE TO START OVER.
Name (first name first) email. Four Digit Student Code
2) Press Ctrl + N at the same time. This action will open a second browser window. In one window you will read these directions and fill in answers, in the other you will launch the DDViewer, the mapping application upon which this exercise is built. You can use Alt + Tab to switch quickly between the two open browser windows.
3) In the second browser window, click on the link to the right à http://www.ciesin.org
4) Click on the Online Tools and Applications link on the left hand tool bar.
5) Scroll down to the United States & Mexico Demographic Data Viewer (US-MEX DDViewer) link and click on it. This will launch the viewer’s “home page”.
6) Click on the words “Launch DDViewer 3.1” and give it a moment to load.
7) You should see the windows in figure 1 below.
Figure 1
8) Next you need to select the regions you wish to further inspect or analyze. Make sure the Select radial button is selected, so you can select the region labeled “US-Border”. Click on the region including California. See Figure 2 below. Then click “Get States” button
9) Using your cursor, click on the outline of California. What you have indicated to the software by highlighting California is that you want to map some variables in the highlighted (now orange) state.
Figure 2
10) Once you have selected California, a green base map of California’s counties will appear. You will need to click on the radial button to the left of the words “Select Box”. This will change your cursor in the map window to a crosshair or plus (+) sign. This will allow you select (highlight in orange) multiple counties. You need to select all 58 counties, so place your crosshair cursor just under the word “About” in the top toolbar, press and hold the left button on your mouse and then pull (click and drag) the mouse down and to the right until you have included all 58 counties. Your resultant map window should look like Figure 3 below.
Figure 3
11) Next you should click on the “Select Vars” button to bring up a dialog box displaying a list of variables that you can use to make a choropleth map. When this dialog box appears, scroll down to the variable ‘TOTPOP2000” and click on it once. Scroll the rest of the way down within Select Variables dialog box and select three more variables: “popchange90_00”, “PCTpopchange90_00” and “popsqmi2000”. These variable abbreviations stand for raw population change from 1990 to 2000, percent population change from 1990 to 2000 and for population density per square mile in 2000 Your dialog box should look like Figure 4 below.
Figure 4
12) In the map window, click on the “Submit Job” button and map will be generated of California’s population by county in the year 2000. Congratulations you have made a map! It should look like the one in Figure 5 below.
Figure 5
13) Drag your mouse over the various counties. You should make note that the name of the county and the statistic currently mapped both appear. For example, in figure 5 above, you’ll note that San Bernadino County displays a population of 1,709, 434.0 persons. Keep this function in mind as you will be asked to answer some questions regarding population.
Questions: Place your answer in the response box at the end of each question.
Question 1: How many counties fall in the lowest (yellow ) population category? Answer:
Question 2: What is the most populous California County? à:
Question 3: What is the population of this most populated California County? à (no commas):
14) Back in the map window, click on the “Customize Map” button.
15) In the “Customize Output” window that appears, you should notice that the variable you’ve mapped has been classified (divided into colors) based upon Quantiles. This means that if you had 100 states, the 25 states with the lowest value for the variable, in our case 2000 population, would be appear in category 1, which is yellow. This is good if the data set you are working with is normally distributed (on the “bell curve”). Population however is not “normally distributed” because some states have less than a million people and some have over 35 million. Some states are way above the average and some are way below average. So another ranging method may be in order if we have data (like population) that is non-normal or skewed.
16) Refer to figure 5 below and select the data classification method Equal Intervals, by clicking the radial button to the left of the words “Eq. intervals”.
This ranging method does not divide the data into an equal number of groups (e.g. quantiles), but instead divides the data into equal ranges. This means if the range of population among US states was from 1 million (smallest state) to 17 million (biggest state) you would have a range of 16 million. By dividing the 16 million by 4 equal intervals, you would put all states with less than 5 million in the lowest category and they would appear yellow on the map. Those with 13 to 17 million would be in the top category and they would appear red on the map. Those in the middle ranges would be light orange and darker orange. See figure 5 below.
17) Examine your map, now that it is divided by equal intervals (sometimes also called equal range).
Question 4: How many states are in the highest (red) category now that the data is mapped according to equal intervals? à
Question 5: If you wanted to portray the potential voting and political power of Southern California, which of the two maps you’ve made would best characterize this uneven political power? A) quantiles or B) equal intervals ? à:
18) If you were from Northern California, you might be interested in knowing whether your part of the state ever had a chance of catching up in terms of population. Therefore, you might want to map recent changes in population growth in northern versus southern California. So in the map window, click on the variable “popchange90_00” to get a map of population increases (or decreases by county during the 1990’s).
Question 6: What county gained the most people during the 1990s? à
19) Is the population change in Southern California as a percentage of existing population large by statewide standards? Is Southern California growing more rapidly than other parts of the state? To answer these questions you need to map the percent of population change during the 1990s. Click on PCTpopchange90_00.
Question 7: What county had the greatest percentage increase in population during the 1990s? à
20) Some counties had negative growth during the 1990s, but this fact does does not appear very well on the map. You can customize the map so those counties that lost population during that decade appear distinct from those that gained population. To customize the map, click on the “Customize Map” button, or activate the Customize Output window if it is already open.
21) In the data box under the words “Enter break Value:” enter the number zero. Then click apply. Examine your map.
Question 8: How many counties had negative growth during the 1990s? à
22) You can further customize the map by entering additional break values of you own choosing. Good cartographic principles might suggest that additional break values be placed at 10 and 20 percent. Enter 10, click apply. Enter 20 and then click apply.
23) You may also want to show on the map more clearly that your data has negative values by using a divergent color scheme. So in the Customize Output window, click on the box of yellow to the right of the number 1. This will open another window dialog box lableled “ColorSpectrum”.
24) This dialog box allows you to customize the colors you would like to use in your map. Since you want to show that negative growth is opposite positive growth, you would probably want to pick a color that would evoke this notion most clearly. I would suggest a green or blue, since those seem opposite the yellow/orange/red color ramp that is the default scheme in the application. Pick a relatively light shade because your negative values are not that large. See figure 6 below for an example.
Figure 6
25) **You WILL NEED to use such a map for this class (and possibly others). If you press Ctrl + Alt and Print Screen simultaneously, the active window will be placed (copied) onto the clipboard. You can paste it into another application (such as Word or Powerpoint) by pasting (Ctrl + V).
26) Finally among the demographic variables, you should map population density. Click on the variable “popsqmi2000” to get a map of population density.
27) Because some of the counties are small, it may be difficult to see them all. You could drag your cursor over all of them hoping to note the highest density county. You could also reclassify the map by equal interval, but you still might not see it because very small counties are sometimes very densely populated. So, click on the “Statistical Info” button in the map window. A new “Statistical Information” window will appear. Scroll through the variables, find the data for population density and answer the questions below (round answer to nearest 1).
Question 9: What is the maximum population density in among counties in California? à persons per square mile
Question 10: What is the mean (average) population density in California? à persons per square mile
28) Unfortunately, this window does not immediately indicate which county has the highest and lowest data values. So click on the radial button next to the words “Tabular Info”, this will produce a table of the values for each of the variables in all 58 counties. Scroll through the values and examine the data.
Question 11: Which county has the highest population density? à persons per square mile.
LANDCOVER AND AGRICULTURE
We can get an idea of why Californians grow what they do, where they do by examining maps of natural landcover. The following section examines this relationship. Before you dash through these remaining questions, take a look over the slide show of landcover maps I have created for you at: http://www.csun.edu/~sg4002/courses/417/417_study/417veghome.htm
29) To examine some of the other data available, you should erase the population variables. In the map window, click “Select Vars” and in the Select Variables dialog window click on the “Clear All Selections” button.
30) Click on the button “Land” at the top bar of buttons in the Select Variables window. Select (click once on) each of the following variables:
a. Percent Grassland
b. Percent Shrubland
c. Percent Mixed Dryland/Irrigated Crop/Pasture
d. Percent Savanna
e. Percent Deciduous/Broadleaf Forest
f. Percent Evergreen/Needleleaf Forest
g. *Percent Percent Wooded Tundra (which is really Percent Barren or Barn_PCT)
31) Click on “Submit Job” in the map window (make sure your counties are all still seleted). A map of Percent Grassland should appear.
32) Click on the “Customize Map” window and select equal intervals as your classification system.
33) Examine the map. Select each of the variables in turn and notice the regional patterns of landcover for each county. Notice the change from north to south, from coastal to interior valley to transmontane (other side of the mountains). Each climate zone has its own set of vegetative cover. Examine the maps in turn and answer the questions below.
Question 12: The presence of grasslands generally indicates that the land is too dry for crops so will be used to produce hay and cattle. Which of the following counties therefore probably have their leading crops in hay and produce much beef?
A. Butte
B. Modoc
C. Santa Clara
D. Ventura
Answerà
Question 13: Savanna is a ground cover that is made up of grasslands mixed with widely space trees (like on Lion King in Africa). If irrigated, this can become prime agricultural lands. Examine the map of Percent Mixed Dryland/Irrigated Crops and note the correlation between Savanna and irrigated cropland. Which of the following California counties has a lot of savanna, but not a lot of irrigated cropland?
A. Kings County
B. Ventura County
C. San Luis Obispo County
D. Inyo County
Answer à
Question 14: The map of deciduous forest is similar to the map of one of California’s most famous agricultural by-products (a beverage). What is this product? à
Question 15: The heavy presence of evergreen-needleaf forests generally suggests that the soil is too poor for many crops (other than trees). The presence of barren land suggests that there is too little water for crops.
Which two parts of the state do you think have the smallest production of food crops?
A. The Central Coast and Central Valley
B. The Northeast and Northwest
C. The Central Valley and the Southwest
D. The Northwest and the Southeastern
34) You may want to click on the submit button now (see step 40 below). You are finished with the data entry component of this exercise, but you must still make a map of your own and compose a brief description of your map to hand in. Instructions are as follows. You may use the back button to return to this page.
35) Make a new map of your own using the Build New Variable function. You can clear the selected variables and chose any of your own, or you can use those agricultural/landuse ones available to you.
36) To make your own variable, click on the button “Build New Vars” in the map window. This will open a the Variable Builder window (see figure 7 below). A list of the variables currently available for mapping will appear in a list. You may add, subtract, multiply and divide these variables in a variety of fashions. You can build equations, etc. You can be as creative as your statistical abilities allow you to be.
In Figure 7 below I have built a very simple new variable that I called CROPLAND, which I made from adding the four landcover categories that mentioned the word “crop” in the variable description. This way I have a new map which shows roughly the distribution cropland in California. It’s Figure 8 below.
37) Once you’ve built a variable, click on the “Apply” button and examine the map window. You will notice your new variable appearing among the list of variables that you can map in the mapper window.
38) Chose your new variable to map and modify it as you see fit. You should open your word processing program (Word or Wordperfect ?)
39) Last, copy and paste the map you’ve made (Ctrl + Alt + Print Screen to copy) into your word processing program as a graphic. You should write several paragraphs describing the map you’ve made, how you made it and what it might indicate to the viewer of the map. You will hand this in upon the due date for this exercise. It will count as your first “writing assignment”.
Figure 7.
Figure 8
STEP 40:
After you have finished filling in each of the input boxes, INCLUDING the input box for your NAME!!!, click on the submit button below. A web page will appear confirming the posting of your answers to the email server. PRINT THE CONFIRMATION PAGE OUT AS EVIDENCE OF YOUR SUBMISSION. USE the back button to complete steps 35 through 39 if you have not yet done so. Thanks.
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If you have comments or suggestions, email me at steve.graves@csun.edu