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Maps By Mitch

A Comparison Study; US Census Bureau data

September 1, 2011

Welcome to "Maps By Mitch". A "blog" of sorts to highlight various maps and the techniques used to create them. I hope to have a new "map" posted on a monthly basis.

This month's map comes from data collected by the US Census Bureau during the 2010 census.  While perusing thier site I located data that contained the median age of men, women, and the total popoluation for each municipality in Columbia County.  The median is being displayed in this case and is typically tied to the average of a dataset.  Unlike last month's map, this month has less geoprocessing and more data entry and cartography.  if you have any questions regarding the methods used, please contact me.

Purpose: To graphically show trends, if any, in the data as well as any anomalies that may exist.

Requirements: 1) The map must contain the median age of men, women and the total population. 2) Graphically display in an easy to understand manner and adhere to proper cartographic techniques and ideals.

Design: In order to create this map I had to collect the data from the US Census Bureau and import it into ArcMap.  This was accomplished by downloading the data from the US Census Bureau as individual Microsoft Excel files, (Figure 1).


Figure 1.

Once I had the individual files added to Microsoft Excel, I merged them into a single file and saved it as an .xls file, which is a standard Excel workbook, (Figure 2).  I then removed any unwanted data from the Excel workbook to simply clean it up, (Figure 3).

Figure 2. / Figure 3.

Figure 4. / Figure 5.

Next was to add the Excel data into Arcmap.  Now this could have been accomplished several ways including a GIS geoprocessing join or relate.  However, in order to use a join or relate I would need to change the Excel workbook to complement the attribute table of the "Municipalities" vector layer.  Instead, I chose to enter the data into ArcMap manually, for the dataset is rather small and in this caseit would be much quicker.  To do this I opened the attribute table for the "Municipalities" layer and added three new fields called"median Age Total", "Median Age Male" and "Median Age Female", (Figure 4 & Figure 5).  Once the fields were added to the attribute table I began adding the data from the Excel file to the corresponding fields in ArcMap, (Figure 6).

Figure 6.

Now that the data has been entered for each feature of the "Municipalities" layer it was time to display it graphically.  First, I decided to display all three fields, "Median Age Total", "Median Age Male" and "Median Age Female" simultaneously.  Therefore, i added three data frames into ArcMap and populated them with the "Municipalities" and "Communities" layers, (Figure 7).

Figure 7.

Next was to symbolize each "Municipalities" layer, renamed "Median Age", via their selected fields which were added to the attribute table in a prior step.  After adding a consistent symbology to the "Median Age" layer in each data frame i provided the appropriate range and labels, (Figure 8). The final step was to add the basic cartographic elements that are necessary for this map.  They included: titles, legends, north arrows, a neat line and a source.

Figure 8.


10/23/2011 5:18:15 AM
You have the monopoly on uefsul information—aren't monopolies illegal? ;)

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