Shrubland 1.0: Statewide Prediction Accuracy

Applying 2022-01-15 shrubland models to all lidar coverages.

Mike Mahoney true
2022-01-15

Evaluation Results

This report is a companion to Shrubland 1.0: The Gang’s All Here. 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: 0.493

Confusion Matrix and Statistics

         1        0
1  1727907 17395571
0   379570 62374609
                                         
               Accuracy : 0.7829         
                 95% CI : (0.7828, 0.783)
    No Information Rate : 0.9743         
    P-Value [Acc > NIR] : 1              
                                         
                  Kappa : 0.1221         
                                         
 Mcnemar's Test P-Value : <2e-16         
                                         
            Sensitivity : 0.81989        
            Specificity : 0.78193        
         Pos Pred Value : 0.09036        
         Neg Pred Value : 0.99395        
             Prevalence : 0.02574        
         Detection Rate : 0.02110        
   Detection Prevalence : 0.23356        
      Balanced Accuracy : 0.80091        
                                         
       'Positive' Class : 1              
                                         

90% Specificity

Threshold: 0.759

Confusion Matrix and Statistics

         1        0
1  1290887  7733699
0   816590 72036481
                                          
               Accuracy : 0.8956          
                 95% CI : (0.8955, 0.8956)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.1985          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.61253         
            Specificity : 0.90305         
         Pos Pred Value : 0.14304         
         Neg Pred Value : 0.98879         
             Prevalence : 0.02574         
         Detection Rate : 0.01577         
   Detection Prevalence : 0.11022         
      Balanced Accuracy : 0.75779         
                                          
       'Positive' Class : 1               
                                          

95% Specificity

Threshold: 0.854

Confusion Matrix and Statistics

         1        0
1   850761  3264302
0  1256716 76505878
                                          
               Accuracy : 0.9448          
                 95% CI : (0.9447, 0.9448)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2478          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.40369         
            Specificity : 0.95908         
         Pos Pred Value : 0.20674         
         Neg Pred Value : 0.98384         
             Prevalence : 0.02574         
         Detection Rate : 0.01039         
   Detection Prevalence : 0.05026         
      Balanced Accuracy : 0.68138         
                                          
       'Positive' Class : 1               
                                          

97.5% Specificity:

Threshold: 0.891

Confusion Matrix and Statistics

         1        0
1   490841  1341543
0  1616636 78428637
                                          
               Accuracy : 0.9639          
                 95% CI : (0.9638, 0.9639)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2307          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.232905        
            Specificity : 0.983182        
         Pos Pred Value : 0.267870        
         Neg Pred Value : 0.979803        
             Prevalence : 0.025739        
         Detection Rate : 0.005995        
   Detection Prevalence : 0.022380        
      Balanced Accuracy : 0.608043        
                                          
       'Positive' Class : 1               
                                          

99% Specificity:

Threshold: 0.910

Confusion Matrix and Statistics

         1        0
1   223049   492771
0  1884428 79277409
                                         
               Accuracy : 0.971          
                 95% CI : (0.9709, 0.971)
    No Information Rate : 0.9743         
    P-Value [Acc > NIR] : 1              
                                         
                  Kappa : 0.1469         
                                         
 Mcnemar's Test P-Value : <2e-16         
                                         
            Sensitivity : 0.105837       
            Specificity : 0.993823       
         Pos Pred Value : 0.311599       
         Neg Pred Value : 0.976782       
             Prevalence : 0.025739       
         Detection Rate : 0.002724       
   Detection Prevalence : 0.008743       
      Balanced Accuracy : 0.549830       
                                         
       '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. 15). CAFRI Labs: Shrubland 1.0: Statewide Prediction Accuracy. Retrieved from https://cafri-labs.github.io/acceptable-growing-stock/posts/shrubland-10-statewide-prediction-accuracy/

BibTeX citation

@misc{mahoney2022shrubland,
  author = {Mahoney, Mike},
  title = {CAFRI Labs: Shrubland 1.0: Statewide Prediction Accuracy},
  url = {https://cafri-labs.github.io/acceptable-growing-stock/posts/shrubland-10-statewide-prediction-accuracy/},
  year = {2022}
}