NCASI SMDG Home

The NCASI Relative Frequency Function Tool

The Relative Frequency Function (RFF) tool is used for classifying habitat for species. Areas where the species is more likely to be found can be identified. The algorithm compares the relative frequencies of a species’ sample points to that of random points or absence points on the landscape to compute an occurrence ratio. The occurrence ratio r is smoothed across the range of values using moving, overlapping windows. The ratio of frequencies at a sample point for each variable is used to compute the geometric mean score for all data with non-missing values. This score is used to compute the classification cutoff that maximizes classification accuracy. Confidence intervals are computed with cross-validation. The user manual demonstrates the application with case studies in which accuracies above 90% are obtained. The program is for Windows machines and includes a self-contained installer. Input is a simple csv file. Computed models can be saved to a file for later use.

A Publication about RFF theory can be found here .


RFF Tool License Agreement

The RFF source code is copyrighted by NCASI. Anyone may download the executable version of RFF from the NCASI website. Use of RFF for non-commercial purposes is encouraged. All commercial uses of RFF by individuals and organizations other than NCASI member companies are strictly prohibited unless authorized in advance in writing by NCASI. Commercial uses include but are not limited to (a) any use of RFF that has any substantial effect on private forest management; (b) any use of RFF in consulting or other commercial service activities conducted for public-sector or private-sector clients, and (c) any sale of software or software-related services based directly or indirectly on RFF. Internal use of RFF by NCASI member companies is unlimited. Member companies that wish to use RFF for external commercial purposes must pay a supplemental annual fee (in addition to dues). External commercial purposes include but are not limited to: (a) any use of RFF in consulting or other commercial service activities conducted for public-sector or external private-sector clients, and (b) any sale of software or software-related services based directly or indirectly on RFF. The supplemental fee for external use of RFF for a year is $5,000. This fee may be adjusted at the start of each NCASI fiscal year (April 1). If a NCASI member company decides to terminate its membership in NCASI, any and all rights to commercial use of RFF will terminate simultaneously with termination of membership.

You May Download the RFF Tool After Reading the License Agreement

Tool last updated on 12/02/2011
I have read the RFF Tool License Agreement and:
Do Not Accept the Terms

Accept the Terms

The download zip file is 17MB and requires that you allow popups from this site.