Shrubland 1.0.1: Statewide Prediction Accuracy

Applying 2022-01-16 shrubland models to all lidar coverages.

Mike Mahoney true
2022-01-19

Evaluation Results

This report is a companion to Shrubland 1.0.1: Supersize Me. It describes the same models as that document.

The logistic ensemble model was used to predict shrubland in all areas with LiDAR-derived CHMs. Predictions were restricted to only pixels of vegetated LCPRI classes (excluding developed, barren, ice/snow, and water). The predicted probabilities were then classified using four thresholds, documented in the model report document, chosen to target certain values of specificity in order to improve positive predictive value.

These results pool training, validation, and test pixels with the remainder of the state. As only 00.02% of pixels were used in any of these roles, these results are for all practical purposes equal to out-of-bag accuracy.

Confusion Matrices

Optimize Both

Threshold: 0.141

Confusion Matrix and Statistics

         1        0
1  1798249 17924494
0   309228 61845686
                                          
               Accuracy : 0.7773          
                 95% CI : (0.7772, 0.7774)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.124           
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.85327         
            Specificity : 0.77530         
         Pos Pred Value : 0.09118         
         Neg Pred Value : 0.99502         
             Prevalence : 0.02574         
         Detection Rate : 0.02196         
   Detection Prevalence : 0.24088         
      Balanced Accuracy : 0.81428         
                                          
       'Positive' Class : 1               
                                          

90% Specificity

Threshold: 0.332

Confusion Matrix and Statistics

         1        0
1  1408450  7934939
0   699027 71835241
                                          
               Accuracy : 0.8946          
                 95% CI : (0.8945, 0.8946)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2129          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.66831         
            Specificity : 0.90053         
         Pos Pred Value : 0.15074         
         Neg Pred Value : 0.99036         
             Prevalence : 0.02574         
         Detection Rate : 0.01720         
   Detection Prevalence : 0.11411         
      Balanced Accuracy : 0.78442         
                                          
       'Positive' Class : 1               
                                          

95% Specificity

Threshold: 0.523

Confusion Matrix and Statistics

         1        0
1  1103682  4229838
0  1003795 75540342
                                         
               Accuracy : 0.9361         
                 95% CI : (0.936, 0.9361)
    No Information Rate : 0.9743         
    P-Value [Acc > NIR] : 1              
                                         
                  Kappa : 0.2697         
                                         
 Mcnemar's Test P-Value : <2e-16         
                                         
            Sensitivity : 0.52370        
            Specificity : 0.94697        
         Pos Pred Value : 0.20693        
         Neg Pred Value : 0.98689        
             Prevalence : 0.02574        
         Detection Rate : 0.01348        
   Detection Prevalence : 0.06514        
      Balanced Accuracy : 0.73534        
                                         
       'Positive' Class : 1              
                                         

97.5% Specificity:

Threshold: 0.677

Confusion Matrix and Statistics

         1        0
1   819812  2191544
0  1287665 77578636
                                          
               Accuracy : 0.9575          
                 95% CI : (0.9575, 0.9576)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2991          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.38900         
            Specificity : 0.97253         
         Pos Pred Value : 0.27224         
         Neg Pred Value : 0.98367         
             Prevalence : 0.02574         
         Detection Rate : 0.01001         
   Detection Prevalence : 0.03678         
      Balanced Accuracy : 0.68076         
                                          
       'Positive' Class : 1               
                                          

99% Specificity:

Threshold: 0.818

Confusion Matrix and Statistics

         1        0
1   516250   881451
0  1591227 78888729
                                          
               Accuracy : 0.9698          
                 95% CI : (0.9698, 0.9698)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2798          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.244961        
            Specificity : 0.988950        
         Pos Pred Value : 0.369357        
         Neg Pred Value : 0.980228        
             Prevalence : 0.025739        
         Detection Rate : 0.006305        
   Detection Prevalence : 0.017071        
      Balanced Accuracy : 0.616956        
                                          
       'Positive' Class : 1               
                                          

Data Access

Raster files can be downloaded from GitHub at this link.

Files ending in classified have been classified into four categories:

Files not ending in classified represent the binary shrubland maps (1 = shrub) using the threshold specified above.

The probability map is too large to share easily; I’ll be adding it to Labrador in the near future.

Corrections

If you see mistakes or want to suggest changes, please create an issue on the source repository.

Citation

For attribution, please cite this work as

Mahoney (2022, Jan. 19). CAFRI Labs: Shrubland 1.0.1: Statewide Prediction Accuracy. Retrieved from https://cafri-labs.github.io/acceptable-growing-stock/posts/shrubland-101-statewide-prediction-accuracy/

BibTeX citation

@misc{mahoney2022shrubland,
  author = {Mahoney, Mike},
  title = {CAFRI Labs: Shrubland 1.0.1: Statewide Prediction Accuracy},
  url = {https://cafri-labs.github.io/acceptable-growing-stock/posts/shrubland-101-statewide-prediction-accuracy/},
  year = {2022}
}