| # TASK_02_Feature_Extraction |
| |
| **Assignee:** Google Earth Engine Specialist |
| **Role:** Feature Extraction & Stack Generation |
| |
| --- |
| |
| ## 1. Project Overview |
| |
| We are building a Rock Glacier Segmentation Dataset for Himalayan rock glacier mapping. The segmentation labels have already been generated from manually delineated rock glacier polygons. |
| |
| **Current Project Structure:** |
| ```text |
| RockGlacier_Project/ |
| │ |
| ├── EDA/ |
| │ ├── individual_polygons/ |
| │ │ ├── polygon_0.geojson |
| │ │ ├── polygon_1.geojson |
| │ │ └── ... |
| │ └── individual_plots/ |
| │ |
| ├── masks/ |
| │ ├── mask_0000.tif |
| │ ├── mask_0001.tif |
| │ └── ... |
| │ |
| ├── features/ |
| └── dataset/ |
| ``` |
| |
| - **Polygons:** Located at `EDA/individual_polygons/` (e.g., `polygon_0.geojson`) |
| - **Masks:** Already generated and located at `masks/` (e.g., `mask_0000.tif`) |
| - **Mask Values:** `0` = Background, `1` = Rock Glacier |
| |
| --- |
| |
| ## 2. Objective |
| |
| Generate georeferenced multi-band feature stacks from Google Earth Engine for every rock glacier polygon. The generated features **must align perfectly** with their corresponding masks. |
| |
| > [!WARNING] |
| > **Important Notes** |
| > This is a semantic segmentation project. |
| > - **Do NOT** create polygon-level statistics. |
| > - **Do NOT** calculate mean NDVI, mean slope, mean elevation, etc. |
| > - **Do NOT** generate CSV tables. |
| > |
| > We explicitly need pixel-level feature images (rasters). |
| |
| --- |
| |
| ## 3. Data Sources & Required Features |
| |
| Use **Google Earth Engine** to extract the following: |
| |
| **Primary Imagery:** Sentinel-2 Surface Reflectance |
| **Terrain:** Copernicus DEM (preferred) |
| |
| ### Required Bands/Features: |
| **Sentinel-2 Bands:** |
| - Blue (B2) |
| - Green (B3) |
| - Red (B4) |
| - NIR (B8) |
| - SWIR1 (B11) |
| - SWIR2 (B12) |
| |
| **Spectral Indices:** |
| - NDVI |
| - NDWI |
| - NDSI |
| |
| **Terrain Features:** |
| - Elevation |
| - Slope |
| - Aspect |
| |
| *If feasible, also include:* |
| - Land Surface Temperature (LST) |
| - Surface Velocity |
| |
| --- |
| |
| ## 4. Technical Specifications |
| |
| ### Spatial Resolution |
| All outputs must use exactly **10 meter spatial resolution**. |
| - **Reason:** Sentinel-2 native resolution is 10m. The masks and features must have absolutely identical spatial resolutions to prevent dimension mismatch during U-Net training. |
| |
| ### Extraction Strategy |
| For each polygon, perform the following sequence: |
| 1. Load `polygon_i.geojson` |
| 2. Compute bounding box |
| 3. Add **200 meter padding** around the bounding box. *(Note: This padding allows future segmentation models to see surrounding terrain context, not just the glacier).* |
| 4. Download all required features for this bounds area. |
| 5. Clip features to the padded region. |
| 6. Resample all layers to exactly 10m resolution. |
| 7. Stack all features into a single multi-band GeoTIFF. |
| |
| ### Output Location |
| Save all generated feature stacks inside the `features/` directory: |
| ```text |
| features/ |
| ├── feature_0000.tif |
| ├── feature_0001.tif |
| ├── feature_0002.tif |
| └── ... |
| ``` |
| |
| --- |
| |
| ## 5. Band Order Specification |
| |
| Your final GeoTIFF stacks must strictly follow this band ordering: |
| - **Band 1** = Blue |
| - **Band 2** = Green |
| - **Band 3** = Red |
| - **Band 4** = NIR |
| - **Band 5** = SWIR1 |
| - **Band 6** = SWIR2 |
| - **Band 7** = NDVI |
| - **Band 8** = NDWI |
| - **Band 9** = NDSI |
| - **Band 10** = Elevation |
| - **Band 11** = Slope |
| - **Band 12** = Aspect |
| |
| *Optional (if acquired):* |
| - **Band 13** = LST |
| - **Band 14** = Velocity |
| |
| --- |
| |
| ## 6. Alignment Validation |
| |
| You must physically verify that the features perfectly overlap the masks: |
| - `feature_0000.tif` aligns perfectly with `mask_0000.tif` |
| - `feature_0001.tif` aligns perfectly with `mask_0001.tif` |
| |
| **Checklist for alignment:** |
| - [ ] Matching CRS (Coordinate Reference System) |
| - [ ] Matching Resolution (10m) |
| - [ ] Matching Bounding Box Coordinates |
| - [ ] Exact Pixel-to-Pixel alignment (dimensions must be identical) |
| |
| --- |
| |
| ## 7. Deliverables & Current Scope |
| |
| **What you must deliver:** |
| 1. Google Earth Engine extraction script. |
| 2. Feature stack generation pipeline. |
| 3. Validation script (to verify alignment checklist above). |
| 4. Documentation explaining each generated feature. |
| 5. Feature extraction report. |
| |
| > [!IMPORTANT] |
| > **Strict Scope Limitations** |
| > - Only perform feature extraction and feature stack generation. |
| > - **Do NOT** create train/validation/test splits. |
| > - **Do NOT** generate patches. |
| > - **Do NOT** train any machine learning model. |
| > |
| > The sole goal of this task is to produce correctly aligned multi-band feature stacks for all rock glacier masks. |
| |
