Lab#7

The first map displays the Asian population in America. In the map, there are six levels of Asian's density, with darker color representing high density and light color representing low density. We can tell from the color on the map that there is a great population of Asian people distributing on the West Coast and North-East Coast of America, while the population in the central part of America is small, which matches my experience before. UCLA has a big amount of Asian students while one of my friend who studies in a university in central America told me Asian students take up a rather small amount of percentage in her school. As we can see from the map, Los Angeles is one of the cities with most Asians.

THe second map represents the distribution of Black people in America. Like the distribution of Asian people, most black people live on the east and west coast. The most direct indication from the map is that there is a very distinct difference of the black population in the north and south area. The black people in the south area are much more than those in the north area. which can be contributed to the historical reason. Some areas in the central north have rather small distribution and the black people in certain south area can take up to more than 80%.

The third map represents the distribution of some other races in America.Same as the rule in the maps above, the dark color represents the high concentration while the light color represents the low concentration. We can tell from the map that in the border areas adjacent to other countries, the concentration of other races is high. For example, in the West Coast, the Hispanic population is big, which may result from the geographic position. The overall concentration of the concentration, however, is not very high.

In conclusion, the maps above indicate the diverse population in America. The most diverse population distributes on the coast areas where immigrants take up a big amount of percentage. In my opinion, as time goes by, the population of certain races on the coast areas will scatter and in the near future we might not see such a distinct difference of population distribution in America.

In this lab, we use the American Lambert Conformal Conic projection in GIS to represent a customer-friendly map of population. This projection provides the viewers a direct visual sense of how different races be distribute in a certain area, with different colors. GIS is a powerful tool to summarize and visualize geographic data and convey useful information to the mass.

Above is the image information of a mountain area in California. I chose this area because it can provide distinct data about the elevation. The top edge native is 27.5722 degree. The bottom edge native is 27.570833 degree. The left edge native is -112.9899999 degree and the right edge native is -112.9886111 degree. The data is from the GCS North American 1983. The four different maps display different views about the terrain, which includes a shaded relief model, an aspect map. a slope map and a 3-D representation of the map.

lab #5

The maps above are created to show different features using different geographic method. As we can perceive from these maps, the equidistant maps preserve the distance; the equal area maps preserve the area; the confrontal maps preserve the angle locally. These characteristic projections display contrasting information for the viewers: the equidistant maps always havee very skwed angles and areas; the equal area maps have distorted angles and distances ; the confrontal maps project skewed areas and distances.

Each kind of projection has its own purpose and needs to present the world. As the projections transform the 3-D reference ellipsoid into a 2-D map, the on different levels distort the earth surface depending on various needs of the map. Therefor no maps represent the exact earth surface. And each projection has its own advantages and pitfalls. For example, the mercator maps mainly serve for nautical purposes as they always preseve right angles at the intersections of longtitude and latitude, being able to display the linear scale towards all directions. In the equal area maps, relative sizes are shown, but shapes and directions are distorted. This kind of maps make it possible for a visual presentation of the land on the earth foratlases and classroom use.

Althought all these projections are useful for people's lives in one way or another, there are many perils in utilizing them because while each kind of maps correctly portray some aspects, they distort others aspects at the same time. In other words, there is no one single exactly correct maps and there is no best map. The best map is the one which can show certain characteristics which we are looking for.

Despite the pitfalls of map projections, there is still musch benefitial potentials in using projections: we are allowed to view the geographic data in a 2-D way in a convenient and fast way. And I believe that it is always our pursuit to find out a better way to represent the world with the lowest level of inaccuracies.