extern double armin(int, float *);
extern double armax(int, float *);
extern void Initialize(int, float [], float [], int, int,
float [], float []);
int ReadData(int, float *, float *, float *);
float **MakeGrid(int, int, float *, float *);
void c_nngetslopes(int, int, float *, int *);
void c_nngetaspects(int, int, float *, int *);
void c_nnpntinits(int, float [], float [], float []);
extern void c_nnpnts(float, float, float *);
void c_nnpntend();