Stratified estimation of map accuracy and area

Stratified estimation of map accuracy and area after Card (1982). The stratified estimator accounts for disproportional allocation of samples within the strata.

Usage

aa_card(
  data,
  w = NULL,
  strata = NULL,
  area = NULL,
  confusion_matrix = T,
  olofsson = T
)

Arguments

data: confusion matrix or cbind(reference,map)
w: stratum weights
strata: stratum names
area: total area (optional)
confusion_matrix: (default=T) define if data contains a confusion matrix or sample vectors
olofsson: (default=TRUE) uses Olofsson formula instead of Card to estimate standard errors of reference class proportions and OA.

Value

list of accuracy and area proportion estimates and associated standard errors

Details

Map agreement

References

Card, D.H. (1982). Using Known Map Category Marginal Frequencies to Improve Estimates of Thematic Map Accuracy. Photogrammetric Engineering and Remote Sensing, 48, 431-439

Olofsson, P., Foody, G.M., Stehman, S.V., & Woodcock, C.E. (2013). Making better use of accuracy data in land change studies: Estimating accuracy and area and quantifying uncertainty using stratified estimation. Remote Sensing of Environment, 129, 122-131

Author

Dirk Pflugmacher

Examples

  
m <- matrix(c(410,67,26,369), nrow=2)
A <- c(828837,33067283)
w_j <- A/sum(A)
aa_card(m, w_j)
#> $cm
#>      [,1] [,2]
#> [1,]  410   26
#> [2,]   67  369
#> 
#> $cmp
#>           1           2
#> 1 0.0229941 0.001458163
#> 2 0.1499122 0.825635581
#> 
#> $stats
#>   class        ua       pa       p_i     p_i_se      ua_se        pa_se
#> 1     1 0.9403670 0.132986 0.1729063 0.01687046 0.01134094 0.0130331827
#> 2     2 0.8463303 0.998237 0.8270937 0.01687046 0.01727113 0.0003366146
#>            w
#> 1 0.02445227
#> 2 0.97554773
#> 
#> $accuracy
#> [1] 0.84862969 0.01687046
#> 
#> $area
#>   class proportion proportion_ci
#> 1     1  0.1729063    0.03306609
#> 2     2  0.8270937    0.03306609
#>