shotGroups (version 0.3)

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 = c('0', '1', '2'), dstTarget = 100,
              conversion = 'm2cm', target = c('BDS25m', 'DSB25m'), caliber=9)

## S3 method for class 'data.frame':
groupLocation(xy, level = 0.95, plots = c('0', '1', '2'), dstTarget = 100,
              conversion = 'm2cm', target = c('BDS25m', 'DSB25m'), caliber=9)

## S3 method for class 'default':
groupLocation(xy, level = 0.95, plots = c('0', '1', '2'), dstTarget = 100,
              conversion = 'm2cm', target = c('BDS25m', 'DSB25m'), caliber=9)

Arguments

xy

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

a numerical value indicating whether a 2D-scatterplot should be shown. 0: no plot, 1: regular scatterplot, 2: scatterplot with added target in the background (this feature is incomplete and experimental).

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.

target

a character string indicating the target type to be drawn in the scatterplot. Currently, only two types of pistol targets are supported.

caliber

a numerical value indicating the bullet diameter in mm. Only used with plots='2'.

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.
• ctrXci
  parametric (t) and bootstrap (basic, BCa) confidence intervals for center x-coordinate (1499 replicates).
• ctrYci
  parametric (t) and bootstrap (basic, BCa) confidence intervals for center y-coordinate (1499 replicates).
• ctrRob
  robust estimate of group center offset relative to point of aim (MCD algorithm).
• distPOA
  distance from group center to point of aim (in original measurement units and MOA).
• distPOArob
  distance from robust estimate of group center to point of aim (in original measurement units and MOA).
• Hotelling
  Hotelling's T^2-Test result from testing if group center equals point of aim.

See Also

getMOA, covMcd, anova.mlm, boot, boot.ci

Examples

# coordinates given by a suitable data frame
res <- groupLocation(DFsavage, dstTarget=100, conversion='m2mm',
                     level=0.95, plots=2, target='BDS', caliber=7.62)
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,
              target='BDS25m', caliber=9)