Geog 7 Lab 7

The first map in the top left corner shows the change in population throughout the country from 1990 to 2000, the years when the census was taken.  The values were calculated by taking count within the census, and applying the data within the tables.  The map's color ramp is appropriate for this kind of data because the areas of greatest change are denoted by dark green, denoting that this area is prospering.  Like crops, the greener it is, the better.  The pink colors seem appropriate because they are very light and show that population is lightening up in these areas.  In fact, it is decreasing in these areas.

The second map in the top right corner shows the number of people in different areas around the country in the year 2000.  The values in this map, much like the values in the other map, were likely calculated by the counts taken within the census in the year 2000.  The map shows similar statistics to the first map.  The middle of the country, encompassing the Great Plains and much of states such as Idaho, Wyoming and Montana, has the least population, with much of these towns averaging less than 10,000 people.  The color ramp, like the other map, seems appropriate, because the greatest populations are the darkest, while the lightest populations are in a light blue color.  The colors clearly transition nicely from the middle of the country outwards, as the greatest populations do seem to be near the coasts, such as in California, New York and Florida, and cities like Chicago which is near Lake Michigan, another large water source.

The third map in the lower left corner shows the percentage change in population between 1990 and 2000.  This is likely the most accurate depiction of the population change in different areas, as it is based on percentages based on the areas' original numbers, not just a display of actual numbers as in the first map.  In that map, it is obvious that the big cities will have the greatest amount of people, but that does not necessarily mean that the percentage change is the greatest.  These values were calculated by taking the rough count of the change in population and likely dividing this by the midpoint between the population of 1990 and 2000.  This color ramp is very good for this type of map because it clearly displays the areas which have a greatly increased percentage in population, and also a very obvious color for areas which have decreased percentage in population greatly.  Everything else in between is rather nonchalant, which shows just basic percentage changes in population either way

The fourth map in the lower right corner shows the population density calculated in the year 2000.  These values were calculated by dividing the populations of different towns by the entire national population.  Based on these numbers, the map can be created to show which areas have the greatest populations.  And as this graph shows, the greatest population density, not surprisingly, is centered around the major cities throughout the United States.  What is also apparent from this map is that, besides the major populations centers, there seems to be much greatest population density overall in the eastern half of the United States versus the western half.  The color ramp seems appropriate because it clearly displays the areas of greatest population density, yet at the same time shows clearly which areas have the least population.  The most important part though is that one can also distinctly see which areas have medium population density, as these closer are distinct from the areas of highest population density as well as the areas of lowest population.