groupLocation: Accuracy: Location measures for a single group of bullet holes

Description

Calculates location measures for a single group of bullet holes.

Usage

groupLocation(xy, level = 0.95, plots = TRUE, bootCI = c('basic', 'bca'),
              dstTarget = 100, conversion = 'm2cm')

## S3 method for class 'data.frame':
groupLocation(xy, level = 0.95, plots = TRUE, bootCI = c('basic', 'bca'),
              dstTarget = 100, conversion = 'm2cm')

## S3 method for class 'default':
groupLocation(xy, level = 0.95, plots = TRUE, bootCI = c('basic', 'bca'),
              dstTarget = 100, conversion = 'm2cm')

Arguments

either a numerical (n x 2)-matrix with the (x,y)-coordinates of n points (1 row of coordinates per point), or a data frame with either the variables X, Y or Point.X, Point.Y as well as Aim.X

level

a numerical value giving the level for the confidence intervals for the center (x,y)-coordinates.

plots

logical: show a 2D-scatterplot?

bootCI

a character vector to select which bootstrap confidence interval type to report. Possible types are 'none' (no bootstrap CI), 'norm', 'basic', 'perc', 'bca'. See

dstTarget

a numerical value giving the distance to the target - used in MOA calculation. See getMOA.

conversion

how to convert the measurement unit for distance to target to that of the (x,y)-coordinates - used in MOA calculation. See getMOA.

Value

A list with the results from the numerical analyses and statistical tests.
ctr(x,y)-offset of group center relative to point of aim.
ctrXciparametric (t) and bootstrap confidence intervals for center x-coordinate.
ctrYciparametric (t) and bootstrap confidence intervals for center y-coordinate.
ctrRobrobust estimate of group center offset relative to point of aim (MCD algorithm).
distPOAdistance from group center to point of aim (in original measurement units, MOA, SMOA, milliradian).
distPOArobdistance from robust estimate of group center to point of aim (in original measurement units, MOA, SMOA, milliradian).
HotellingHotelling's T^2-Test result from testing if group center equals point of aim.

Details

The number of replicates for the reported bootstrap confidence intervals is at least 1499. If the BCa interval is reported, it is at least the number of points.

Examples

Run this code

# coordinates given by a suitable data frame
res <- groupLocation(DFsavage, dstTarget=100, conversion='m2mm',
                     level=0.95, plots=2, bootCI='basic')
names(res)
res$ctr
res$distPOA
res$ctrXci
res$ctrYci

# coordinates given by a matrix
# assume data from pistol shooting at 25m with 9mm ammo
# metric units
xy <- matrix(round(rnorm(100, 0, 5), 2), ncol=2)
groupLocation(xy, dstTarget=25, conversion='m2cm', plots=2)

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