Topographic Analysis Using Slope and Aspect Mapping with SRTM DEM in Google Earth Engine

Description

This product provides high-resolution topographic insights into China’s terrain by generating slope and aspect maps using the Shuttle Radar Topography Mission (SRTM) DEM. Utilizing the powerful cloud-based geospatial platform Google Earth Engine (GEE), this analysis computes and visualizes:

1. Aspect Map:

Aspect represents the compass direction that a slope faces. It is useful in:

• Hydrological modeling

• Solar radiation analysis

• Land use planning

• Agricultural zoning

The aspect values are visualized with a color palette ranging from blue → green → red representing different directional orientations (0° to 360°).

2. Slope Map:

Slope is the measure of steepness or incline of the terrain. This is essential for:

• Landslide risk assessment

• Infrastructure planning (roads, buildings)

• Soil erosion studies

• Agricultural machinery feasibility

The slope values are visualized from 0° (flat) to 90° (vertical) using a palette from black → yellow → orange → red, highlighting elevation gradients.

3. Digital Elevation Model (DEM):

The raw elevation data clipped to China’s boundary is also visualized for contextual understanding. The elevation is styled using a terrain color scale (black → light green → brown).

📤 Deliverables:

• High-quality GeoTIFF files of Slope and Aspect layers (30-meter resolution)

• Ready-to-use outputs for GIS applications, modeling, or environmental analysis

• Exports available directly to your Google Drive

• CRS: EPSG:4326 (WGS 84)

🔍Use Cases:

• Environmental Impact Assessments (EIA)

• Solar farm site selection

• Forest and watershed management

• Risk zoning in mountainous regions

• Terrain modeling for real estate and infrastructure

📂 Technical Workflow Summary:

1. Load China’s administrative boundaries from FAO GAUL.

2. Import NASA’s SRTM 30m DEM.

3. Clip the DEM to China’s boundary.

4. Generate and visualize Aspect and Slope using GEE’s ee.Terrain functions.

5. Export the results as GeoTIFFs for offline use or integration in GIS software.