Here are the representation of Census collected by the US Census department regarding the ethnicity of "Asian", "Black", and "Some other race".
The above two pictures are the representation of census regarding "Asian" in the United States. Notice that the first picture tells the distribution of the exact absolute number of Asian population by counties. The second picture, tells the distribution of the percentage of Asian population by counties. Notice the differences between two pictures: In terms of the absolute number of population, most Asian populations are resided in the Southern California region, while some in reside in Washington, East Coast New York region, Texas, and Florida. On the other hand in the percentage distribution, there are lot more shaded counties where Asian reside. This proves that there are Asian people living in other countries that I have not mentioned above. The number is very low though, and it only became significant to stand out from the overall census when we calculate with percentage, that a few Asians will just "pop out" easily in a small area of county that the majority ethnicity is not Asian.
In this graphical comparison of "Black" ethnicity, the difference between the calculation of distribution of absolute number and percentage became very obvious. If someone was asked "where do you think most African American people reside now?" They might have answered either "Los angeles or Southern United States", and both answers are right, depends on the context of reference. In the year of 2000-2010, most African American people, in terms of total number live in Southern California, Los Angeles area. However, the percentage of concentration of African American people is still high in the Southern states. Why is that? One possible reason is that counties in Southern United States might be comparably smaller in terms of area, compare to the counties else where in the United States. Thus, the ratio of the few residing African American people in Southern states over the actual area of the county will be high. Another reason might be that there is actually a very high concentration of African American population in the Southern United States compare to the region of Los Angeles in Southern California. California is known to be "a melting pot", where a mixture of various ethnicity creates the diversity of the state. So, even though there are a lot of African American people reside in the Southern California region in terms of absolute number, other ethnicities might have a high number of population reside in Southern California at the same time. We cannot exclusively conclude that Southern California, the Los Angeles region is full of African American people choose to reside. We must make a conclusion that is valid and includes the context of the data.
The graphical representation of the "Some Other Race" data is another reinforcement of my argument, that we must make conclusions base on the context of the data. For example, in terms of absolute concentration, states such as California and Arizona is very diverse, because a lot of people of the ethnicities other than Asian and Black reside in the two states. However, their concentration is high mostly in the Southwestern United States and the coastal lines of the Eastern United States, with a few blocks in the inland region here and there. The sparse blocks of their concentration here and there, may means that their actual population is so few in some small area counties that they stand out when we calculate the data in terms of the percentage.
Also, we must note that, besides the context of the data distribution is important, the classification of the data is important as well. In this practice, we are looking at the population distribution in terms of counties. We need to remember that the classification number must be low. Or, in another way to say it in terms of statistics, the numerical range must be high. This way, counties with similar census will be easily gathered and compared. The more the detailed comparison and classification of data, the harder we can compare and make conclusions. The more we are using the ArcGIS software now, the more I am amazed at how convenient this software can provide for us. It is extremely well built for data analyzation, I am impressed at how this software is complexly written to save us time on analyzing the data. Once again, this exercise reinforce the idea that, even though the ArcGIS is extremely convenient and easy for us to make conclusions at a shorter time, we MUST know what we are analyzing. The way we are "manipulating" the data can provide very different results, thus very different conclusions. Even though we need less time now, we must realize and understand that the connivence that ArcGIS bring to us is to let us have more time to undergo scientific research, not to produce conclusions carelessly.
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