How to Create A Simple Pennyslvania Map
Using BusinessMap
There are three primary
tasks involved in creating a map with your own zip code data in BusinessMap:
This cheat sheet will guide
you through each of these three steps.
Preparing
Your Data Back
The easiest way to format
your data so that BusinessMap can import it is to create your data file in
Excel. I'll assume you already know how
to create an Excel file, so these steps are the steps you'll follow once you
have an Excel file.
- Open the Excel file. In order for BusinessMap to properly import the file, you
should have only one column of data.
The column should be named ZIP (for zip codes), and should contain
a list of the zip codes you want to map.
- Save the file as a DBF 4 (dBASE IV) file. This file format only allows you to
save one sheet in a workbook at a time.
Make sure the sheet you want is the active sheet when you are
saving. Repeat the procedure for
as many worksheets as you need to save.
- Your data file is now ready to import into
BusinessMap.
Adding
Your Zip Code Data Back
Now that your data file is
ready, we can import it into BusinessMap.
Open BusinessMap Pro, and
select the Create a New Map option from the start page.
Select the No Template Option
from the list of options.
At the Add Layer dialogue
box, navigate to the /States/PA folder.
Select the PA_CNTY.shp file.
This file is a file that contains information on the location of
theboundaries of PA counties and click OK.
You will now see a map of PA
counties on your screen. It should look
like this.
Now we will add your Zip
code data to the map. Select File – Add
Layer – Databases.
In the Add Database Layer
dialogue box, select the By 5 digit zip code option and continue.
Navigate to the directory
you saved you .dbf file to (as in Preparing Your Data) and continue.
Name the data layer
something sensible. Don't use abbreviations
– the title you give the layer here will appear in the legend. Check to make sure that the Zip code field
matches the name of the Zip code field in your .dbf file (if you followed the
instructions in Preparing Your Data, this field should be called ZIP).
The dialogue box should now
inform you how many of your records have been successfully mapped. If some of them have not been mapped, you
should check your .dbf file to make sure that all of the zip codes are
valid. Some potential problems are APO
zip codes (which are not in PA or on the US map) or zip codes with too few or
too many digits.
Now you can choose what type
of symbol you want to represent the zip codes you are mapping. You can change the symbol's size, shape and
color here.
The result should look
something like this.
You can repeat this as many
times as you need to add layers to your map.
To "turn a layer off" (i.e. make it non-visible), simply click
its checkbox in the Layer Status window.
Similarly check a layer to make it visible.
Creating
a Choropleth Map back
So what is a choropleth
map? Most of you probably see at least
one in the paper everyday, but just don't know what a choropleth map is.
Quite simply, it is a type
of map in which the areas shown on the map (e.g. states, counties, census
tracts) are assigned a color value that corresponds to some data value. This type of map is usually only made when
the data you are representing are somehow normalized. Examples of such data are: per capita income, median age, and percent
of persons holding a bachelor's degree or higher.
You might want to make this
kind of map if you wanted to see demographic information along with the
locations of your survey respondents.
So in this example, we'll
use the same survey data we used in Adding Zip Code Data,
adding some demographic data to make the
map more informative.
First select Edit-Color Coding.
Then select the Color Code
geographic areas by numerical values option from the Color Code Options
dialogue box (this is the default selection), and click Next.
If you have more than one layer
loaded into your BusinessMap file (e.g. counties and census tracts), you will
have to select which layer you want to color code. In this case, we have only got counties loaded, so we can
continue.
You will now see the Color
Key Code dialogue box. In this box,
there are several options to specify. In
the Color tab, the first step is to select which demographic variable to map by
clicking on the Field pull-down menu.
For this type of map, since
we are representing data that is ordered (i.e. we are showing quantitative
differences rather than qualitative differences), we should use color value
rather than color hue to represent different categories. Color hues are what we call color in
vernacular language – different hues are red, green and blue. Color value, on the other hand, refers to
the lightness or darkness of a single hue.
That is, we would pick one hue (e.g. green) and represent low data
values with a lighter shade of green and high data values with a darker shade
of green.
After choosing a variable,
you need to decide how many categories you would like to divide the data into. The human eye is really only able to
distinguish five or six different values of a color well, so I would recommend
using four or five categories for most maps.
This can be specified with the Ranges Number drop-down menu.
After specifying the number
of categories you want to use, you have to select a method of calculating the
ranges. The two types of calculation
methods BusinessMap offers are Equal Number of Objects in Every Range and Equal
Size Ranges.
In the Equal Number of
Objects in Every Range method, the computer orders the data values from low
to high and divides the data into however many groups you specified in the
Ranges Number drop-down menu. This calculation method is appropriate when you
want to show something about the distribution of the data values you are
representing (e.g. when representing the age of the population).
The Equal Size Ranges
method calculates the minimum and maximum of the data values and divides the data
range into the number of categories you specified. In this method, there might some categories
that don't get mapped at all. For
example, if you were mapping percent of persons with at least a bachelor's
degree by county, and you used the Equal Size Range method to divide the
possible data values into five categories, the top category would be those
counties where at least 80% of the residents have at least a bachelor's degree. It is unlikely that such a county exists,
but this method is appropriate for mapping variables when you want to make
comparisons based on a particular value across counties, or to find all of the
counties where at least X% of the residents have at least a bachelor's degree.
In the Color Key Code
dialogue box, there are also a couple of other things you can change. If for example you wanted your lowest value
to be white, and the highest value dark green, you could select the first
category and change its color to white with the Color button in the
Current Range attributes box. After
selecting both a beginning and an ending color for your scheme, you can use the
Ramp Colors button (as shown in the graphic below) to have the computer
calculate the colors in between.
Finally, you can change the text of each category's description in the
legend by modifying the text in the Legend Text box.
One thing that is nice to do
is to change the text of the Legend categories. You'll notice in the graphic above that the legend categories are
inclusive – that is, the first category ends at 0 AND the second category
starts at 0. In practice, the computer
doesn't put the counties that have a value of 0 in both categories. It actually only puts such counties in the
first category. So you can change the
category definitions to reflect this by ending the first category with 0 and
beginning the second category at 0.1.
You can use the Title tab of
the Color Key Options dialogue box to enter in the Legend Title.
When you have changed all of
that, you can click OK and your choropleth map that also shows your survey
respondents' locations will appear.
You'll notice that in addition to the title you specified, there is a
subtitle in the legend box. You can
remove this by double-clicking on the legend box and deleting the subtitle from
the dialogue box that opens up. You can
also add the symbol for your survey participants to the legend by un-checking
the Show Only Last Layer Coded box in the Title tab of the same dialogue box
and adding that layer to the list of presented layers.
Now all that's left is to
add a map title, create any additional labels that you want, and move the
legend, scale and title to positions you like.
You can modify the title by
double-clicking on the map title box or by selecting Edit - Map Title.
The title, legend and scale
can by clicking on them once, holding the mouse button down, and repositioning
the box.
Text labels can be added by putting
BusinessMap into Text mode (click on the A icon below the Preferences menu item.
Next, click the location on
the map where you would like the text to appear, and type the desired text into
the text box, formatting it as desired.
If the box's location is not exactly where you wanted it to be, return
to pointer mode (by clicking the arrow icon) and pick it up and move it as you
would move a the legend or the title.
At this point, you should
have a finished map!
