Available with Spatial Analyst license.
To create training samples, use the training sample drawing tools on the Image Classification toolbar.
- On the toolbar, choose an appropriate image layer in the Layer list.
- Click the draw button. Notice that there is a choice of four drawing tools available: polygons, circles, rectangles, and select segment.
For the Select Segment drawing option to be available, the image layer in the Layer list must be a segmented raster layer.
- In the map display, identify an area that belongs to a known class. Use the drawing tool to define a training sample.
The following image shows a polygon training sample:
When choosing polygon segments in Select Segment mode, one mouse click highlights the segment and a second click captures the segment as a training polygon. Since a segment is a single object with average attribute values, a statistically significant number of segments (about 15-20) need to be collected to represent a class.
Once you finish drawing or selecting the training sample, a new class is created in Training Sample Manager with a default name, value, and color.
- In the manager, optionally change the class name, value, and color for the class.
- Repeat steps 2 through 4 to create a few more training samples to represent the rest of the classes in the image.
The following screen shot shows how manager appears after five classes were created: