What is the difference between a geographic coordinate system and a projected Coordinate System?

What is the difference between a geographic coordinate system and a projected Coordinate System?

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 the shapefile Coordinate System?

1. In ArcCatalog, click the shapefile whose coordinate system you want to define.
2. Click the File menu and click Properties.
3. Click the XY Coordinate System tab.
4. Click Modify.
5. Follow the steps for defining either a new geographic or a new projected coordinate system to change the appropriate parameters.
6. Click OK.

Why does ArcGIS not show geographic coordinate systems warning?

This Geographic Coordinate Systems Warning dialog box will not appear if you add data later that does not have the map or globe’s coordinate system if you have set a geographic transformation. If the transformation is between the same coordinate systems, it will treat the set one as the default.

How to identify an unknown geographic coordinate system?

One by one, expand the folders, click a State Plane projection file, then click Apply. The Geographic Coordinate Systems warning box may appear to warn you that the layer’s geographic coordinate system is not the same as the data frame’s geographic coordinate system.

What does projecting the data mean in ArcMap?

This is often called projecting the data. If the source and target coordinate system do not use the same geographic coordinate system, data can be shifted anywhere from a few meters to hundreds of meters from the correct locations. The table lists any data sources that you are adding and their geographic coordinate systems.

How to find an unknown coordinate system in ArcMap?

Start ArcMap with a new empty map and add the data with the unknown coordinate system. The data must not have a defined coordinate system. For shapefiles, it must not have a PRJ file.