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How many segments are needed for a class in ArcGIS?
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.
How are training samples generated in ArcGIS Pro?
Available with Spatial Analyst license. In supervised image classification, you need to train the classifier to assign pixels or objects to a given class using training samples. The class categories are determined by your classification schema, and the training samples can be generated using the Training Samples Manager pane.
How does image classification work in ArcGIS Pro?
The image classification algorithm uses the training samples, saved as a feature class, to identify the land cover classes in the entire image. You can view and manage training samples by adding, grouping, or removing them. When you select a training sample, it is selected on the map.
How many segments are in a training sample?
For example, if eight segments were collected as training samples for a class, it may not be a statistically significant number of samples for reliable classification.
How to create a polygon training sample in ArcGIS?
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.
How are segments represented in a classification model?
Instead of classifying pixels the process classifies segments, which can be thought of as super pixels. Each segment, or super pixel, is represented by a set of attributes that are used by the classifier tools to produce the classified image. Below is a geoprocessing model that shows the object-oriented feature extraction workflow.
How are image segmentation and classification tools used?
Available with Spatial Analyst license. Segmentation and classification tools provide an approach to extracting features from imagery based on objects. These objects are created via an image segmentation process where pixels in close proximity and having similar spectral characteristics are grouped together into a segment.