Projection is the most important thing when mapping to get right. If not it can seriously affect the quality of the map produced. every map has a coordinate system, however due to the fact that the earth is spherical and a map will be a flat surface some system of projection is likely to have occurred. however during projection changes, the shape and size of polygons and line, and the angles between these entities will likely change. This means that a coherent map, with every layer displaying features in the correct place, will have all its features projected to the same coordinate system. However, ARCGIS has a feature which allows ‘projection-on-the-fly’. Projecting-on-the-fly is useful within ArcMap in order for different data sets that have been recorded on different coordinate systems to be combined without actually changing much of the data. Projecting on the fly can work on new versions of GIS, but anyone with older software is likely to struggle with the ‘on-the-fly’ projection, making the map unreadable and therefore unusable.
Also during this assignment, I worked with vector and LANDSAT remote sensing raster data. Using remote sensing layers can be useful as it shows the exact satellite image from the area, giving rich, interesting information which is hard to display with vector data. Furthermore LANDSAT remote sensing has been operational for a large amount of time meaning that long term comparison of a changing environment can be shown.
During this assignment:
- I gained understanding of the importance of projection with maps, and how poor projection practices can lead to maps that show completely the wrong thing.
- Gained hands on experience with the process of changing projections within ARCGIS.