The orthogonal dispersion of a set of points can be described using the standard deviation of the x- and y-coordinates of a set of point observations. The orthogonal dispersion can then be visualized with a Standard Deviation Box. This function computes the properties of the Standard Deviation Box (SD Box) from a set of point observations.

1 2 |

`id` |
A unique integer to identify a SD Box |

`filename` |
A string indicating the ASCII textfile where the box coordinates will be written |

`centre.xy` |
A vector of length 2, containing the x- and y-coordinates of the geographic centre of the SD Box |

`calccentre` |
Boolean: Set to TRUE if the mean center is to be calculated |

`weighted` |
Boolean: Set to TRUE if the weighted mean center is to be computed with weighted coordinates |

`weights` |
Weights applied to point observations, number of weights should equal the number of observations |

`points` |
A 2-column matrix or data frame containing the set of point observations input to the calc_box function |

`verbose` |
Boolean: Set to TRUE if extensive feedback is desired on the standard output |

Use the boxloc (coordinates) and boxatt(attributes) to produce shapefiles using the convert.to.shapefile and write.shapefile from the shapefiles library

The returned result is a list:

`id` |
Identifier for the SD Box shape - it should be unique |

`calccentre` |
Boolean: TRUE if the mean centre was estimated |

`weighted` |
Boolean: TRUE if the weighted mean centre was estimated |

`CENTRE.x` |
X-coordinate of the centre |

`CENTRE.y` |
Y-coordinate of the centre |

`SD.x` |
Orthogonal standard deviation in the x-axis |

`SD.y` |
Orthogonal standard deviation in the y-axis |

`Box.area` |
Area of the standard deviation box |

`NW.coord` |
North-west coordinates of SD Box |

`NE.coord` |
North-east coordinates of SD Box |

`SW.coord` |
South-west coordinates of SD Box |

`SE.coord` |
South-east coordinates of SD Box |

Results are stored in the r.BOX object (required for plot_box). This function can be used on its own (once) or repetitively in a loop to process grouped point data stored in a larger table. When used repetitively, be sure to increment the id parameter to ensure that each SD BOX has a unique identifier. The output ASCII coordinate file can be further processed using the shapefiles package to generate an ESRI Shapefile for SD BOX polygons.

Randy Bui, Ron N. Buliung, Tarmo K. Remmel

`plot_box`

, `calc_sde`

, `calc_sdd`

,
`wtd.var`

1 2 3 4 5 6 7 8 9 | ```
## BOX example
calc_box(id=1, filename="BOX_Output.txt", centre.xy=NULL, calccentre=TRUE,
weighted=FALSE, weights=NULL, points=activities, verbose=FALSE)
## plot_box by default takes as input the result produced from the calc_box, read from the current workspace.
## SD Box to shapefile example (exclude the comments below to run script)
## shp <- convert.to.shapefile(boxloc,boxatt,"id",5)
## write.shapefile(shp, "BOX_Shape", arcgis=T)
``` |

Questions? Problems? Suggestions? Tweet to @rdrrHQ or email at ian@mutexlabs.com.

All documentation is copyright its authors; we didn't write any of that.