Statewide Shrubland Prediction Accuracy

Applying 2022-01-12 shrubland models to all lidar coverages.

Mike Mahoney true
2022-01-12

Evaluation Results

This report is a companion to Shrubland 0.0.1: Making It Happen. 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: 0.416

Confusion Matrix and Statistics

         1        0
1  1790234 20837811
0   317255 58932889
                                          
               Accuracy : 0.7416          
                 95% CI : (0.7415, 0.7417)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.1025          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.84946         
            Specificity : 0.73878         
         Pos Pred Value : 0.07912         
         Neg Pred Value : 0.99465         
             Prevalence : 0.02574         
         Detection Rate : 0.02186         
   Detection Prevalence : 0.27636         
      Balanced Accuracy : 0.79412         
                                          
       'Positive' Class : 1               
                                          

95% Specificity

Threshold: 0.848

Confusion Matrix and Statistics

         1        0
1   831553  3394254
0  1275936 76376446
                                         
               Accuracy : 0.943          
                 95% CI : (0.9429, 0.943)
    No Information Rate : 0.9743         
    P-Value [Acc > NIR] : 1              
                                         
                  Kappa : 0.2364         
                                         
 Mcnemar's Test P-Value : <2e-16         
                                         
            Sensitivity : 0.39457        
            Specificity : 0.95745        
         Pos Pred Value : 0.19678        
         Neg Pred Value : 0.98357        
             Prevalence : 0.02574        
         Detection Rate : 0.01016        
   Detection Prevalence : 0.05161        
      Balanced Accuracy : 0.67601        
                                         
       'Positive' Class : 1              
                                         

97.5% Specificity:

Threshold: 0.882

Confusion Matrix and Statistics

         1        0
1   513678  1565742
0  1593811 78204958
                                          
               Accuracy : 0.9614          
                 95% CI : (0.9614, 0.9615)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2256          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.243739        
            Specificity : 0.980372        
         Pos Pred Value : 0.247029        
         Neg Pred Value : 0.980027        
             Prevalence : 0.025739        
         Detection Rate : 0.006274        
   Detection Prevalence : 0.025397        
      Balanced Accuracy : 0.612056        
                                          
       'Positive' Class : 1               
                                          

99% Specificity:

Threshold: 0.902

Confusion Matrix and Statistics

         1        0
1   260243   626483
0  1847246 79144217
                                          
               Accuracy : 0.9698          
                 95% CI : (0.9698, 0.9698)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.161           
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.123485        
            Specificity : 0.992146        
         Pos Pred Value : 0.293488        
         Neg Pred Value : 0.977192        
             Prevalence : 0.025739        
         Detection Rate : 0.003178        
   Detection Prevalence : 0.010830        
      Balanced Accuracy : 0.557816        
                                          
       '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. 12). CAFRI Labs: Statewide Shrubland Prediction Accuracy. Retrieved from https://cafri-labs.github.io/acceptable-growing-stock/posts/statewide-shrubland-prediction-accuracy/

BibTeX citation

@misc{mahoney2022statewide,
  author = {Mahoney, Mike},
  title = {CAFRI Labs: Statewide Shrubland Prediction Accuracy},
  url = {https://cafri-labs.github.io/acceptable-growing-stock/posts/statewide-shrubland-prediction-accuracy/},
  year = {2022}
}