@@ -154,7 +154,7 @@ storing spatial information, and the **ggplot2**-package (Wickham, 2009) for vis
## Algorithms
The basic idea is to distribute sampling points evenly over the study area by selecting these points in compact spatial strata. Compact strata can be obtained by _k_-means clustering of the cells making up a fine grid representing the study area of interest. Two _k_-means algorithms have been implemented in the **spcosa**-package: a transfer algorithm and a swopping algorithm (Walvoort _et al_, 2010). The transfer algorithm obtains compact clusters (strata) by transferring cells from one cluster to the other, whereas the swopping algorithm achieves this by swopping cells between clusters. The first algorithm results in compact clusters, whereas the second algorithm results in compact clusters of equal size. For reasons of efficiency, both algorithms have been implemented in the [Java](http://www.java.com) language and communicate with **R** (R Core Team, 2015) by means of the **rJava**-package (Urbanek, 2013).
The basic idea is to distribute sampling points evenly over the study area by selecting these points in compact spatial strata. Compact strata can be obtained by _k_-means clustering of the cells making up a fine grid representing the study area of interest. Two _k_-means algorithms have been implemented in the **spcosa**-package: a transfer algorithm and a swopping algorithm (Walvoort _et al_, 2010). The transfer algorithm obtains compact clusters (strata) by transferring cells from one cluster to the other, whereas the swopping algorithm achieves this by swopping cells between clusters. The first algorithm results in compact clusters, whereas the second algorithm results in compact clusters of equal size. For reasons of efficiency, both algorithms have been implemented in the [Java](https://www.java.com) language and communicate with **R** (R Core Team, 2015) by means of the **rJava**-package (Urbanek, 2013).
