In order to fix misaligned and improperly referenced spatial data, you must take into account properties such as areas, angles, distance and direction. When data is projected into a different coordinate system, these four properties can be compromised and a map is said to be distorted. For instance, a Mercator projection of the world distorts the area of countries and maintains the angles. Take for example Alaska and Brazil, they appear to be the same size when in reality, Brazil is significantly larger. On the other hand, a Peters’ projection of the world distorts the angles and shapes of countries but, maintains their true area. The “projecting-on-the-fly” method allows you to combine separate layers with different projected coordinate systems in order to align them onto one map projection. As well, you can use the ArcToolbox Project and Transformation commands which will allow you to combine separate layers with the same projected coordinate systems by changing the coordinates of the layers to align with each other. These commands help align different layers onto one map projection, however one changes the coordinates (ArcToolbox Project and Transformation) and one changes the coordinate system (“projecting-on-the-fly”).

In order to prevent misaligned and improperly referenced spatial data, we can use the remote sensing technique called Landsat to provide us with more accurate data for geographic analysis. Advantages to using Landsat are that the images from Landsat have been collected since 1972 and contain a lot of data within the set. This can tell us about land use, water, agriculture and a multitude of other aspects and how they have changed over the years.