CART Model for Black-Odorous Water Body Identification
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Solution Overview
Problem
Current remote sensing methods for identifying black-odorous water bodies lack objectivity in threshold setting and rely on single features, leading to low accuracy in distinguishing between black-odorous and general water bodies.
Innovation Solution
A method utilizing a Classification and Regression Tree (CART) classification model that selects multiple sampling points, monitors chemical indicators, extracts remote sensing reflectance data, and constructs a decision tree based on spectral change features to classify black-odorous water bodies, incorporating multiple features for accurate identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threshold segmentation method is used based on spectral difference, then black-odorous water bodies can be identified, but threshold selection relies excessively on expert experience leading to non-objective and inconsistent results
Solution Approach 1:
The CART classification model performs self-learning from training data to automatically determine optimal thresholds and classification rules. The model selects spectral features and sets thresholds through iterative training on labeled black-odorous and non-black-odorous water body samples, eliminating the need for manual expert threshold setting while maintaining scientific objectivity and consistency.
Solution Approach 2:
The model uses feedback from training data to continuously optimize classification thresholds. During the training phase, the model learns from labeled samples and adjusts its internal parameters and thresholds based on classification performance, creating a self-improving system that adapts to different water body conditions without requiring repeated expert intervention.
2Ease of manufacture
If single feature classification is used, then the method is simple, but spectral features of some black-odorous water bodies are similar to general water bodies resulting in low accuracy
Solution Approach 1:
The CART classification model merges multiple spectral features (including but not limited to blue band, green band, red band, near-infrared band reflectance values) into a comprehensive classification system. The model evaluates combinations of these features together to distinguish black-odorous water bodies, leveraging the complementary information from each spectral band to improve overall identification accuracy while maintaining a unified analytical framework.
Solution Approach 2:
The model transitions from single-feature analysis to multi-dimensional spectral space analysis. By considering multiple spectral bands simultaneously and evaluating their combined effects through the decision tree structure, the model creates additional discriminative dimensions that enable better separation between black-odorous and non-black-odorous water bodies that cannot be distinguished using single features alone.
Data Source
AI summary
A method for extracting a black-odorous water body based on a CART classification model includes: selecting a research region, designing sampling points within the region; monitoring relevant chemical indicators of the water body at various sampling points, extracting remote sensing reflectance data of the water body, determining a type of the water body according to a classification standard of relevant chemical indicators for an urban black-odorous water body; comparing and analyzing the remote sensing reflectance data to obtain spectral change features of the black-odorous water body and a general water body; constructing each node of a decision tree according to the spectral change features and based on Gini index, constructing a decision tree classification model to obtain classification results of the black-odorous water body and the general water body, calculating a classification accuracy; analyzing the classification results to obtain spatiotemporal distribution changes of black-odorous water bodies in the region.


