← Back to all projects

TOPEX Interactive & Satellite Gravity Studio

Created: January 2022 · Major Upgrade (v2.0 WebGL 2.0 & Potential Field Studio): 2026

TOPEX/Poseidon & Sandwell-Smith is a global satellite altimetry platform developed by the Scripps Institution of Oceanography, UC San Diego (SIO/UCSD) providing global high-resolution marine gravity anomalies and bathymetry grids. The raw endpoint returns unformatted text streams with strict server-side bounding limits, making regional exploration and geophysical modeling cumbersome.

TOPEX Interactive (v2.0) transforms this into an edge-powered, WebGL 2.0 GPU-accelerated scientific platform — featuring zero-latency client-side processing, complete marine & continental Bouguer anomaly reduction with Hayford-Bowie terrain correction, interactive Parasnis linear regression, multi-field GPU heatmap shader rasterization, interactive 2D potential field cross-section profiler with full derivative calculus (FHD, SVD, TDR), automated Elkins (1951) structural fault classification, and multi-format export suites (Oasis Montaj .XYZ, Surfer .GRD, Geosoft .GXF, CSV, GeoTIFF, and high-DPI publication plates).

Live demo: topex-interactive.yufajjiru.work

Step 1: Global spatial grid extraction with live location search and Google Earth satellite layers

TOPEX Interactive — Spatial Extraction & Leaflet Search

Step 2: Complete Bouguer anomaly reduction engine with Hayford-Bowie terrain correction & Parasnis density regression

TOPEX Interactive — Bouguer Reduction & Parasnis Regression

Step 3: WebGL 2.0 Satellite Gravity Studio with 3-field GPU heatmaps, 2D cross-section calculus profiler, and multi-sounding probe

TOPEX Interactive — Satellite Gravity Studio

Key Capabilities & Architecture

1. High-Performance Edge Streaming & JIT Recovery

  • Cloudflare Workers & Hono API: Ultra-low-latency edge proxy handling streaming coordinate requests, CORS negotiation, and fault-tolerant upstream data chunking.
  • Canonical 0.5° Snap-to-Grid: Slices arbitrary user bounding boxes into standard 0.5∘×0.5∘0.5^\circ \times 0.5^\circ discrete tiles, guaranteeing 100%100\% global edge cache reuse across concurrent users.
  • Resumable Stream Engine: Quarantines truncated CGI streams and automatically resumes missing tiles in 0 ms0\text{ ms} directly from client-side IndexedDB.
  • Progressive Web App (PWA): Installable on Desktop, iOS, and Android with offline asset caching and touch gesture controls.

2. Complete Bouguer Gravity Anomaly Reduction & Terrain Engine

  • Marine & Continental Slab Correction:
    • Continental (h≥0h \ge 0): BA=FAA−2πGρch+TC\text{BA} = \text{FAA} - 2\pi G \rho_c h + \text{TC}
    • Oceanic (h<0h < 0): BA=FAA−2πG(ρc−ρw)h+TC\text{BA} = \text{FAA} - 2\pi G (\rho_c - \rho_w) h + \text{TC}
  • Hayford-Bowie & Hammer Terrain Correction: Integrates regional terrain prism corrections into Complete Bouguer Anomalies (CBA) with dynamic marine density adjustments.
  • Parasnis & Nettleton Linear Regression:
    • Automatically computes least-squares empirical crustal density from the sounding data cloud (ΔgFAA=m⋅h+c  ⟹  ρreg=m2πG\Delta g_{\text{FAA}} = m \cdot h + c \implies \rho_{\text{reg}} = \frac{m}{2\pi G}).
    • Interactive scatter plot comparing the empirical regression slope against manual density estimates.
    • Rigorous academic literature citations (Parasnis 1952, Nettleton 1939, Telford et al. 1990, Sandwell & Smith 1997).

3. WebGL 2.0 & GLSL Hardware Shader Acceleration

  • GPU Fragment Shaders: Real-time multi-colormap mapping (Viridis, Coolwarm, Turbo, Jet, Spectral, Earth/Ocean Bathymetry) executed entirely on the GPU via custom GLSL shaders.
  • Vectorized Single-Pass Matrix Builder: Coordinates, unique sorted spatial axes, and cell index maps are generated in a single pass for all 5 potential fields simultaneously (5×5\times performance gain over multi-pass loops).
  • Hardware Bilinear & Bicubic Interpolation: Utilizes WebGL 2.0 32-bit floating-point textures (OES_texture_float_linear / EXT_color_buffer_float) for zero-latency raster resampling during high-DPI viewport pan and zoom.
  • Graceful Headless Fallback: Automatically detects GPU capability limits and provides a headless export view without application lockup.

4. 2D Potential Field Calculus & Fault Interpretation Profiler

  • Multi-Line Survey Cross-Sections: Freely draw, stack, and compare transect lines (A→A′A \to A', B→B′B \to B') with synchronized dual-panel distance-elevation-anomaly plots.
  • Full Potential Field Derivative Suite:
    • First Horizontal Derivative (FHD): Highlights maximum horizontal gradient inflection boundaries across structural contacts.
    • Second Vertical Derivative (SVD): Solves Laplace's equation (∇2g=0  ⟹  ∂2g∂z2=−∂2g∂x2\nabla^2 g = 0 \implies \frac{\partial^2 g}{\partial z^2} = -\frac{\partial^2 g}{\partial x^2}) for high-resolution basement edge detection.
    • Tilt Derivative (TDR): Automatic Gain Control (AGC) phase angle filter (θ=tan⁡−1[VDR/THDR]\theta = \tan^{-1}[\text{VDR}/\text{THDR}]) normalizing amplitude decay for deep and shallow basement depth estimation (h=Δx45∘h = \Delta x_{45^\circ}).
  • Elkins (1951) Fault Classification Engine: Automated real-time structural analysis classifying normal faults, thrust/reverse faults, and strike-slip/transtensional steps based on SVD peak-to-trough dipole amplitude ratios.
  • Sounding Picks Inspection Table: Interactive multi-pin sounding markers with dynamic channel visibility filtering and embedded high-DPI cross-section PNG reporting.

5. Industry-Standard Geophysical Deliverables

  • Oasis Montaj .XYZ: Formatted point database for Seequent Oasis Montaj, GM-SYS, and forward gravity modeling.
  • Surfer ASCII Grid .GRD: Golden Software Surfer matrix format.
  • Geosoft Grid .GXF: ASCII grid format compatible with GIS, QGIS, and geophysical modeling software.
  • Publication Composite Plate (4K PNG): High-resolution single-image poster uniting all 3 anomaly maps, colorbars, transect line, 2D cross-section chart, value callouts, and reduction parameters table.
  • GeoTIFF & GeoJSON: 3D Point and raster features for direct drag-and-drop into QGIS and ArcGIS.

Technical Stack

LayerTechnology
Frontend FrameworkReact 18, TypeScript, Vite, PWA (vite-plugin-pwa)
GPU & GraphicsWebGL 2.0, GLSL Fragment Shaders, HTML5 Canvas 2D, SVG HUD Data Graphics
Mapping & SpatialLeaflet, Leaflet-Draw, Nominatim Geocoding, Google Earth Satellite Layer
Backend & EdgeCloudflare Workers, Hono, Cloudflare Cache API, Node.js / TypeScript
Geophysics AlgorithmsBullard-A Reduction, Hayford-Bowie Terrain Correction, Parasnis Regression, FHD, SVD, Tilt Derivative (TDR), Elkins (1951)
Package & ExportOasis Montaj .XYZ, Surfer .GRD, Geosoft .GXF, GeoTIFF, GeoJSON, JSZip, High-DPI PNG Exporters
Upstream Data SourceSIO / UCSD Sandwell & Smith Satellite Altimetry Model
Deployment & HostingCloudflare Workers (Custom Domain: topex-interactive.yufajjiru.work)

License & Usage

  • License: Free Commercial Use License (No Commercial Redistribution)
  • Usage: Free for commercial exploration, geotechnical assessment, client deliverables, and academic research.

Project Links