aspace (version 4.0.1)

calc_box: Calculate the Standard Deviation Box

Description

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.

Usage

calc_box(id=1, centre.xy=NULL, calccentre=TRUE, weighted=FALSE,
weights=NULL, points=NULL, verbose=FALSE)

Value

The returned result is a list:

TYPE

The type of calculation results stored in the object: BOX, SDD, SDE, CF, or CF2PTS

DATE

The date and time that the function was run

LOCATIONS

Locations pertinent for the BOX that can be used with ATTRIBUTES if wishing to build a vector point file for geographic data outside of this pacakge.

FORPLOTTING

Coordinates and identifiers used for plotting by plot_box()

ATTRIBUTES

Attributes for the output BOX that can be used with LOCATIONS coordinates if wishing to build a vector point file for geographic data outside of this package.

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

Arguments

id

A unique integer to identify a SD Box

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

Author

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

Details

Use the LOCATIONS element in the output list object along with the ATTRIBUTES elements can be used to produce shapefiles or other vector point files for geographic data.

See Also

plot_box, calc_sde, calc_sdd, wtd.var

Examples

# BOX EXAMPLE
data(activities)
a <- calc_box(id=1, centre.xy=NULL, points=activities)
str(a)
print(a)

# IF THE RESULT OF THIS FUNCTION IS STORED TO AN OBJECT, THE plot_box()
# FUNCTION WILL TAKE THAT OBJECT AS INPUT FOR PLOTTING VIA THE datin ARGUMENT

# BOX TO SHAPEFILE EXAMPLE (REMOVE THE COMMENTS TO RUN)
# shp <- convert.to.shapefile(a$LOCATIONS, a$ATTRIBUTES, "id", 5)
# write.shapefile(shp, "BOX_Shape", arcgis=T)