How does roctool choose negative samples?

gtkfi / ArcSDM

Spatial Data Modeler 6 for ArcGIS Pro

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How does roctool choose negative samples? #127

Closed letter1225 closed 4 years ago

letter1225 commented 4 years ago

Thank you for the excellent ArcSDM toolbox, it really has helped me a lot. Now I have one question: how does the roctool determine negative samples in plotting a ROC curve if I only input the shapefile of positive points? Thank you very much!

kkorhone commented 4 years ago

If the negatives are not provided, the tool chooses them randomly. The tool does this 10,000 times in order to detemine confidence intervals for the ROC curve and AUC value.

letter1225 commented 4 years ago

Thank you very much. Does the tool randomly choose the same number of negative samples as positive samples each time?

kkorhone commented 4 years ago

Yes, exactly like that.

artolaiho commented 4 years ago

This issue is probably solved.