What is the difference between the projected coordinate system and the geographic coordinate system in ArcGIS?
A geographic coordinate system (GCS) is a reference framework that defines the locations of features on a model of the earth. A projected coordinate system (PCS) is flat. It contains a GCS, but it converts that GCS into a flat surface, using math (the projection algorithm) and other parameters.
How do I change a shapefile Coordinate System?
- In ArcCatalog, click the shapefile whose coordinate system you want to define.
- Click the File menu and click Properties.
- Click the XY Coordinate System tab.
- Click Modify.
- Follow the steps for defining either a new geographic or a new projected coordinate system to change the appropriate parameters.
- Click OK.
When to use ArcGIS to apply a transformation?
ArcGIS will apply a transformation appropriately based on the input and output geographic coordinate systems. If a pair of geographic coordinate systems does not have any transformations, it is sometimes possible to build a chain of transformations by using a third geographic coordinate system.
What are the coordinate systems in ArcGIS Pro?
In ArcGIS Pro, both maps and their layers have coordinate systems, and they are not always the same. Each coordinate system may be either geographic or projected. Projected coordinate systems always include an underlying geographic coordinate system.
Can a geographic transformation be used in any direction?
Even though a geographic transformation has a built-in directionality, all transformation methods are inversible. That is, a transformation can be used in either direction. ArcGIS will apply a transformation appropriately based on the input and output geographic coordinate systems.
When do you not need a geographic datum transformation?
If layers have a different projected coordinate system than the map they are in, but both the layers and the map reference the same underlying geographic coordinate system, a transformation is not needed.