When new layers are added in ArcGIS Pro, such as the “no_projection.shp” file, a warning may appear indicating: “Unknown Coordinate System ‘Map2’ data source is missing coordinate system information. Click here to view details.” This means that the added layer lacks a defined spatial reference system, likely because no coordinate system was set during its creation.
It is important not to assign a coordinate system arbitrarily. The correct coordinate system must be known and verified before defining it. Assigning the wrong coordinate system may result in incorrect positioning of the data.
To define the coordinate system of a vector or raster layer, follow this path:
Geoprocessing > Toolboxes > Data Management Tools > Projections and Transformations > Define Projection
In the “Define Projection” tool, configure the parameters as follows:
- Input Dataset or Feature Class: Select the vector or raster layer that lacks a projection, such as “no_projection”.
- Coordinate System: Choose the correct coordinate system. For example, go to Projected Coordinate Systems > UTM > WGS 1984 > Southern Hemisphere > WGS 1984 UTM Zone 17S.
Defining a coordinate system for a layer.
After configuring these parameters, click “OK” to apply the changes. The selected layer will then have a defined spatial reference, ensuring that it aligns correctly with other geographic data in the project.