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What is the difference between project and define projection?
If your data doesn’t have a coordinate system, or you suspect it has the wrong one, you want Define Projection. If your data already has a coordinate system but you wish to convert it into a different one, you want Project. Here’s an analogy: You bought some things online.
How do I project a layer in ArcGIS?
Procedure
- Open the ArcToolbox Projection wizard. ArcGIS 9.x.
- Select the shapefile or geodatabase to be projected. ArcGIS 9.x.
- Specify a location and name for the new projected data.
- Specify the output coordinate system to project the data.
- Select an optional geographic transformation, if required.
- Complete the projection.
How to define a projection for an ArcGIS layer?
Define Projection: This tool allows you to tell ArcGIS what projection/coordiates/datum a layer is using, if such information wasn’t included with the layer (layer Properties shows Unknown projection under Source). You can also define the projection in ArcCatalog. Online help.
What happens when the first layer of ArcGIS is undefined?
If the first layer has undefined geographic (latitude/longitude) coordinates, then ArcGIS discerns degrees and the cursor’s position will display as degrees, but the Data Frame properties will still show an unknown coordinate system. Subsequent unprojected lat/long layers will overlay properly, but projected layers won’t.
How to overlay unprojected Lat and long layers?
Subsequent unprojected lat/long layers will overlay properly, but projected layers won’t. To get them to overlay, you must define the unknown layers’ projections, then also define the Data Frame’s coordinates.
How to choose a georeferencing layer in ArcMap?
Select: Drill down through lists of Geographic or Projected coordinate systems to choose one. Import: Pick another layer that’s already projected the way you want to choose its projection. Geographic transformations: Choosing a datum transformation method is sometimes necessary when using the Project Tool.