Shrubland 1.0.2: Statewide Prediction Accuracy

Applying 2022-01-21 shrubland models to all lidar coverages.

Mike Mahoney true
2022-01-22

Evaluation Results

This report is a companion to Shrubland 1.0.2: Balanced Diet. 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: 0.489

Confusion Matrix and Statistics

         1        0
1  1807278 17342880
0   300211 62427820
                                          
               Accuracy : 0.7845          
                 95% CI : (0.7844, 0.7846)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.1297          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.85755         
            Specificity : 0.78259         
         Pos Pred Value : 0.09437         
         Neg Pred Value : 0.99521         
             Prevalence : 0.02574         
         Detection Rate : 0.02207         
   Detection Prevalence : 0.23389         
      Balanced Accuracy : 0.82007         
                                          
       'Positive' Class : 1               
                                          

90% Specificity

Threshold: 0.755

Confusion Matrix and Statistics

         1        0
1  1451903  8282306
0   655586 71488394
                                          
               Accuracy : 0.8908          
                 95% CI : (0.8908, 0.8909)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2119          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.68893         
            Specificity : 0.89617         
         Pos Pred Value : 0.14915         
         Neg Pred Value : 0.99091         
             Prevalence : 0.02574         
         Detection Rate : 0.01773         
   Detection Prevalence : 0.11889         
      Balanced Accuracy : 0.79255         
                                          
       'Positive' Class : 1               
                                          

95% Specificity

Threshold: 0.840

Confusion Matrix and Statistics

         1        0
1  1083602  3875692
0  1023887 75895008
                                          
               Accuracy : 0.9402          
                 95% CI : (0.9401, 0.9402)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2807          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.51417         
            Specificity : 0.95141         
         Pos Pred Value : 0.21850         
         Neg Pred Value : 0.98669         
             Prevalence : 0.02574         
         Detection Rate : 0.01323         
   Detection Prevalence : 0.06057         
      Balanced Accuracy : 0.73279         
                                          
       'Positive' Class : 1               
                                          

99% Specificity:

Threshold: 0.907

Confusion Matrix and Statistics

         1        0
1   519993   861375
0  1587496 78909325
                                          
               Accuracy : 0.9701          
                 95% CI : (0.9701, 0.9701)
    No Information Rate : 0.9743          
    P-Value [Acc > NIR] : 1               
                                          
                  Kappa : 0.2835          
                                          
 Mcnemar's Test P-Value : <2e-16          
                                          
            Sensitivity : 0.246736        
            Specificity : 0.989202        
         Pos Pred Value : 0.376433        
         Neg Pred Value : 0.980279        
             Prevalence : 0.025739        
         Detection Rate : 0.006351        
   Detection Prevalence : 0.016871        
      Balanced Accuracy : 0.617969        
                                          
       '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. 22). CAFRI Labs: Shrubland 1.0.2: Statewide Prediction Accuracy. Retrieved from https://cafri-labs.github.io/acceptable-growing-stock/posts/shrubland-102-statewide-prediction-accuracy/

BibTeX citation

@misc{mahoney2022shrubland,
  author = {Mahoney, Mike},
  title = {CAFRI Labs: Shrubland 1.0.2: Statewide Prediction Accuracy},
  url = {https://cafri-labs.github.io/acceptable-growing-stock/posts/shrubland-102-statewide-prediction-accuracy/},
  year = {2022}
}