Choosing layers for the PAAT session
Before you can start digitizing points in a Positional Accuracy Assessment tool (PAAT) session, there are several parameters that must be configured. These parameters are presented to you in a wizard that allows you to choose the layers; the color of the grid, if applicable; the reporting units; the field names for the evaluation methods; and the evaluation units.
When you initially choose the layers, you are indicating what is going to be evaluated and what is going to be used as the reference. You can use feature classes or rasters for one or both of the layers. However, when the raster is a digital elevation model (DEM), the reference layer must be a z-enabled point feature class.
Both the data layer and the reference layer need to be in the same projection and datum to ensure the results are accurate.
If the layers do not have a spatial reference defined, the results of the PAAT session will be incorrect.
- Start ArcMap.
- If necessary, load data in the map.
- On the main menu, click Customize > Toolbars > Data Reviewer.
- On the Data Reviewer toolbar, click Data Reviewer > Positional Accuracy Assessment.
The Positional Accuracy Assessment toolbar appears.
- Click the Start Session button on the Positional Accuracy Assessment toolbar.
The Welcome to the Positional Accuracy Assessment Tool Wizard dialog box appears.
- Click Next.
The Pick the layer to evaluate and the layer to use as the reference dialog box appears.
- Click the Data Layer drop-down arrow and choose a layer to evaluate.
- Click the Reference Layer drop-down arrow and choose a layer to use as a reference.
- Click Next.