In lab 2 we learned about using ARC GIS to interpret geographic data.
Fixing misaligned and improperly referenced spatial data is critical for producing maps using GIS. ArcCatalog allows management of files and to preview them including seeing the spatial reference information.
Geographic coordinate systems are a 3D coordinate system in which every location on the globe has a specific coordinate designated, generally, by numbers. Projected coordinate systems are a 2D approximation of an area and coordinates so that it can be visualized on a map. Each projected coordinate system also has a geographic coordinate system because in order to make a 2D approximation of a 3D world, you must define starting points where it matches the real 3D world, in this case using a geographic coordinate system.There are two types of possible projection processes. The Projection-on-fly process visually shifts spatial coordinate systems so that map layers seem like they line up. This is useful for looking at maps (such as displaying or printing them), but not dealing with data from maps as it doesn’t actually change any of the data. Projecting a layer using the ArcToolbox Projections and Transformations tools actually changes the data to create a new/different layer with data in a new coordinate system. This allows for calculations and other data manipulations to be done on the new data.
Remotely sensed data allows for precise information about large areas to be taken with relative ease. Landsat data is very useful for geographic analysis because it consists of very frequent satellite images taken across the entire world, with each area being captured every 16 days. It can be used to create colour images, or false colour images which highlight differences in ground cover such as between water, vegetation or dry soil. It has a huge variety of uses, for example in analyzing floodplain migration.
Accomplishment statement
Acquired skills in GIS relating to (among others) map projection and analysis of Landsat data in scenarios including results of natural disasters.
