◊How to Fix Misaligned and Improperly Reference Spatial Data:
When using spatial data to create a map, it is important to have data with consistent projection systems and coordinate systems. If the spatial data systems are inconsistent, it can cause the data to be misrepresented.
In the case they are inconsistent, fix the data by going to its Properties>XY Coordinate System, then selecting the coordinate system that is consistent with the other data.
If there is a layer with an ‘unknown’coordinate system, check the metadata or the original source of the data set to determine the coordinate system/datum that the data was created with.
Next, right-click the layer with the ‘unknown’coordinate system and click Properties.
Finally, access the XY Coordinate System tab, then choose the coordinate system and datum accordingly to the information represented in the metadata.
◊Advantages to Using Remotely Sensed Landsat Data for Geographic Analysis:
Landsat Data is collected through recording the response time of sunlight, and then converting it into spatial data that can be mapped. Landsat Data is especially useful when examining changes on the earth when:
1. the scope is so large that it cannot be recorded through human calibration equipment
2. when recording phenomena that is constantly changing, and therefore requires data to be captured immediately.
Under such conditions, Landsat Data is useful in recording natural events, such as the change in land-use after the explosion of Mount St. Helens, or when recording the transformation of the snow coverage in the Arctic.