GRASS Cluster analysis statistics Library

by GRASS Development Team (https://grass.osgeo.org)

Introduction

This library does a k-means style of cluster analysis. It is currently only used by i.cluster.

The library functions are defined in cluster.h.

#include <grass/cluster.h>

Cluster structure

struct Cluster
{
    int nbands;                 /* number of bands */
    int npoints;                /* number of points */
    DCELL **points;             /* array of points */
    int np;
 
    double *band_sum;           /* sum over each band */
    double *band_sum2;          /* sum of squares over each band */
 
    int *class;                 /* class of each point */
    int *reclass;               /* for removing empty classes  */
    int *count;                 /* number of points in each class */
    int *countdiff;             /* change in count */
    double **sum;               /* sum over band per class */
    double **sumdiff;           /* change in sum */
    double **sum2;              /* sum of squares per band per class */
    double **mean;              /* initial class means */
    struct Signature S;         /* final signature(s) */
 
    int nclasses;               /* number of classes */
    int merge1, merge2;
    int iteration;              /* number of iterations */
    double percent_stable;      /* percentage stable */
};

List of functions

• I_cluster_assign()
• I_cluster_begin()
• I_cluster_clear()
• I_cluster_distinct()
• I_cluster_exec()
• I_cluster_exec_allocate()
• I_cluster_exec_free()
• I_cluster_means()
• I_cluster_merge()
• I_cluster_nclasses()
• I_cluster_point()
• I_cluster_begin_point_set()
• I_cluster_point_part()
• I_cluster_end_point_set()
• I_cluster_reassign()
• I_cluster_reclass()
• I_cluster_separation()
• I_cluster_signatures()
• I_cluster_sum2()