Thursday, May 26, 2011

Lab #7 Census 2000/2010




















The map above shows the distribution of the Black population as a percent, within each county, throughout the United States.  This map is representative of the 2000 census data reports.  The first step in reading this map is to get familiar with the legend that shows what each color represents quantitatively. The dark blue hue illustrates the areas where the percent of the Black population is below 3%.  As you move down the into the light beige you'll see 25% to 35% of the population is Black.  Red of course represents a high percentage (59% and topping out at 86%).  Now looking at the map itself,  It is a raster image produced by joining a map of all U.S. counties, with the 2000 census data, which is what the percent values are based on.  Once you understand what the colors and areas represent, it is easy to notice patterns on various scales.  On the large scale, a generalization can be made that regionally; the South has the highest percentage of Blacks, followed by the Southern East Coast up to New York, and then Northern Midwest, around the Great Lakes.  The West and Northern regions have low percentages of Blacks, with only Counties in major cities showing out of this generalization.  Interpreting this map can be done on a smaller scale as well.  Take California; The Counties with highest percentage Blacks are Los Angeles County, San Bernardino County, and the Counties around  San Francisco.  Generally speaking, the Counties existing on the coast have low percentages, and the metropolitan areas along with the growing urban areas inland have greater percentage.























This map is the same U.S. Counties map, but instead of overlaying the Counties with the 2000 census data for percent of population being Black, it was overlayed with percent of population being Asian. Again, distribution patterns can be seen on a large scale.  The west coast region and the northern east coast show the greatest percentage of Asians.  The interior of the continental U.S. shows little to no distribution pattern with scattered patches of relatively higher percentages of Asians.  Analysing the counties in Washington State, one should notice the high percent values attributed to the counties southeast of Puget Sound.





This last map shows the percent of races that are not categorized as White, Black, American Indian, Asian, and Pacific Islander.  The data used to produce this map therefore mainly represents the Hispanic population, however it does include miscellaneous races as well, but these are relatively negligible.  The most notable pattern illustrated by the map is the high percent values assigned to counties within the border states of California, Arizona, New Mexico, and Texas.  This is related to high number of Mexican immigrants that have settled in the U.S. over time.  There is also some somewhat high percentages assigned to counties along the east coast down to Florida.  This pattern can be attributed to the immigration of Hispanics from the Caribbean to the eastern U.S.


In doing this Lab, I was able to learn some of the methods used in GIS to create some thematic maps representing the counties of the continental U.S., with regards to the percent of the population according to race.  This was achieved by combining spatial data (counties shape file) with attribute data (census statistics) within ArcGIS.  This is an important skill for anyone considering a future in GIS study.

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