Lab 2: This Lab highlighted the importance of coordinate systems and methods of projection. It also helped explain how to change these aspects so that the data can be most useful.

• There are key reasons to pay attention to the projection type used to represent data on a map. For example, the GCS North American 1983 coordinate system is recommended for pilots over the Canada Lambert Conformal Conic coordinate system. This is because the former is a Geodesic map projection, which takes into account the spherical nature of the Earth, whereas the latter is a planar map projection, which does not. ArcMap will accommodate two layers with differing coordinate systems because it is capable of projecting-on-the-fly, but this is not a true representation, as it is aligning layers rather than changing the way the data is projected onto a map. The best way to correct this is by using the ArcToolbox tool, selecting Data Management Tools > Projections and Transformations > Project.

This lab also touched on the differences between raster and vector data. One method of attaining data is through Landsat, which collects raster data.

• The benefit of using remotely sensed Landsat data for geographic analysis is that this method of gathering data is not intrusive, and does not require direct physical contact with that which is being observed. One drawback to Landsat data is the mixed pixel problem. Because each pixel can only represent on attribute at a time, the raster model has to assign additional pixels to convey all the information in the map. This leads to possible inaccuracies in terms of the road’s shape compared to a vector model.