# 00012: The combination of spatial reference and the units used in the layer's proportional symbology is not supported

Using linear units in combination with a geographic coordinate system is invalid when using the proportional symbol symbology option. You cannot represent a layer with proportional symbols whose dataset is defined by a nonlinear geographic coordinate system (in other words, using coordinates in latitude-longitude).

## Solutions

- Change the symbol properties of your map layer to use an alternative for displaying quantities. See About symbolizing layers to represent quantity for more information.
- Alternatively, you can change the coordinate system of your data source to use a projected coordinate system (one that uses linear units for its coordinates). To learn more about coordinate systems, see Projection basics for GIS professionals.

## More information

When representing proportional symbols for a layer in a basemap layer or an optimized map service, a layer must reference a dataset using a projected coordinate system. A projected coordinate system uses a linear unit of measure.

There are also other alternatives for representing quantity in your map layer. For more information, see About symbolizing layers to represent quantity.

You should be aware that not all symbology options for showing quantity are supported for fast map display. See Supported symbology options for more information.