| Title: | Nearest-Neighbor Analysis |
| Version: | 0.0.2.1 |
| Maintainer: | Cristiano Pereira <cristianomp@gmail.com> |
| Description: | Calculates spatial pattern analysis using a T-square sample procedure. This method is based on two measures "x" and "y". "x" - Distance from the random point to the nearest individual. "y" - Distance from individual to its nearest neighbor. This is a methodology commonly used in phytosociology or marine benthos ecology to analyze the species' distribution (random, uniform or clumped patterns). Ludwig & Reynolds (1988, ISBN:0471832359). |
| Depends: | R (≥ 3.4.0) |
| License: | GPL-2 | GPL-3 [expanded from: GPL (≥ 2)] |
| Encoding: | UTF-8 |
| LazyData: | true |
| RoxygenNote: | 6.0.1 |
| NeedsCompilation: | no |
| Packaged: | 2018-04-12 19:13:11 UTC; Cristiano |
| Author: | Cristiano Pereira [aut, cre], Clovis Castro [aut] |
| Repository: | CRAN |
| Date/Publication: | 2018-04-13 08:54:13 UTC |
Calculates Spatial Pattern Analysis usisng a T-square sample procedure.
Description
Calculates Spatial Pattern Analysis usisng a T-square sample procedure.
Usage
nna(x, y)
Arguments
x |
- Distance from the random point to the nearest individual |
y |
- Distance from individual to its nearest neighbor |
Value
Returns the T-Square Index of Spatial Pattern (C); z-score of C; the Distance Index of Dispersion (I); and z-score of I
References
[1] Cottam, G., & Curtis, J. T. (1956). The use of distance measures in phytosociological sampling. Ecology, 37(3), 451-460. doi:10.2307/1930167 [2] Diggle, P. J., Besag, J., & Gleaves, J. T. (1976). Statistical analysis of spatial point patterns by means of distance methods. Biometrics, 659-667. [3] Johnson, R. B., & Zimmer, W. J. (1985). A more powerful test for dispersion using distance measurements. Ecology, 66(5), 1669-1675. doi:10.2307/1938029 [4] Lamacraft, R. R., Friedel, M. H., & Chewings, V. H. (1983). Comparison of distance based density estimates for some arid rangeland vegetation. Austral Ecology, 8(2), 181-187. doi:10.1111/j.1442-9993.1983.tb01605.x [5] Ludwig, J. A., & Reynolds, J. F. (1988). Statistical ecology: a primer in methods and computing (Vol. 1). John Wiley & Sons.
Examples
a=c(7, 19, 11, 18, 12, 27, 23, 27, 12, 8, 2, 4, 10, 18, 19, 8, 3, 9, 4, 5)
b=c(8, 6, 6, 13, 16, 11, 18, 8, 7, 7, 3, 7, 32, 22, 22, 12, 17, 18, 11, 10)
nna(a,b)