Why is This a Problem?

When data is captured, it is done with a specific projection in mind. When the wrong projection is used to display the data, areas, angles, and direction can become deformed—negatively impacting GIS analysis. To prevent this issue, a GIS user needs to ensure that all obtained data sets are properly aligned and referenced. To determine what coordinate datum and projection the data is stored as, check within the ‘Spatial References’ tab in the layer’s properties.

How to Fix the Problem

To fix this problem, select ‘XY Coordinate System’ tab within the layer’s properties and select the appropriate coordinate system. However, if spatial analysis needs to be done, the necessary action is to project the layer. Projecting a layer alters the data and creates a new layer with a different coordinate system. From the ArcToolbox, select Data Management Tools > Projections and Transformations > Project. The ‘Input Dataset’ field should be filled with the name of the file  that you want to change the projection of and the ‘Output Dataset’ field should have the desired projection.

The Use of Remotely Sensed Landsat Imagery

Landsat imagery is a beneficial tool for all GIS analysts to have in their toolbox. Remotely sensed imagery not only provides basic aerial photos to use for analysis, but also captures different wavelengths of energy. These different bands can be used for more advanced analysis regarding vegetation, glaciers, or a multitude of other tasks. Landsat imagery has been collected of the Earth since 1972, providing a visual history of the changes to the Earth’s surface—allowing for analysis on differing timescales.