Parent Topic: PARAMETERS

NSAM

Specifies the number of samples to collect on which to perform the the iterative clustering. This defaults to 262144 if not provided by the user. If the indicated number is large than the total number of pixels in the image then all the pixels in the image will be used.

The time to compute each iteration is proportional to the number of samples used, so using a lot more than the default number of samples can make the clustering process much slower. Also, all the samples are stored in memory, so a large NSAM value can lead to requirements for a lot of memory. With 262144 samples, and five bands of eight bit input data the program would require approximately 1.3MB of memory while with NSAM set to 2000000, it would take 10MB.

 EASI>NSAM=             | Default to the normal 262144 samples
 EASI>NSAM=1500000      | Use up to 1500000 sample pixels

Parent Topic: PARAMETERS
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