Solution for Immersive 3D Terrain & Pipeline Modeling
Unistal transforms terrain and pipeline data into rich 3D models using DEM (digital elevation model) and DTM (digital terrain model) techniques. We generate detailed Civil3D alignments, CAD‑GIS integration, and interactive visuals to simulate proposed routes, earthwork, and cross‑sections. These models support design validation, construction monitoring, and cost‑effective decision‑making throughout the project lifecycle.
Technical Objective
We leverage high-resolution satellite stereo imagery, remote sensing, and GIS computing to design and visualize pipeline alignments in 3D, enabling feasibility analysis, cost estimates, and planning before construction.
Pipeline Alignment, Terrain Modeling & 3D Visualization
Traditional manual alignment methods are replaced with computer-aided 3D models, allowing visualization, comparison of multiple route options, and socio‑economic impact assessment.
Once a final alignment is chosen, working drawings and cost estimates are derived efficiently using the terrain model. The 3D model is used throughout the project — from planning and construction to ongoing monitoring.
Key Features
- Intuitive 3D interaction: users can navigate in real-time, switch views, and generate animations
- Design analysis: cross-sections, earthwork estimates, and alignment review
- Construction visualization: track progress in a virtual environment
- Multidisciplinary integration: combine data from design, GIS, and engineering into a unified model
- Conflict detection: identify design clashes, terrain issues, and visibility problems early
3D Terrain
A digital elevation model (DEM) represents terrain surface elevation, while a digital terrain model (DTM) represents bare ground without objects. DEM/DTM can be generated using remote sensing, DGPS, total stations, and stereoscopic satellite imagery. Factors like terrain roughness, sampling density, grid resolution, and interpolation algorithms influence DEM quality.
Inputs for DTM Model:
- Stereo satellite imagery (4 m LISS)
- Real-time kinematic GPS
- Topographic maps
- Total station surveys
- DGPS-based GCPs
- Inertial surveys
Remote Sensing: The Technology
GIS and remote sensing enable the creation of digital spatial databases using precise navigation, satellite imagery, aerial surveys, and transactional data. Remote sensing facilitates pipeline corridor monitoring, natural resource management, and spatial-temporal analysis.
Remote sensing technology assessment ensures:
- Optimal satellite imagery selection and frequency
- Image processing and mathematical modeling
- Data modeling, security, and system integration
- Survey planning, warnings, and alerts
DGPS Survey for Capturing GCPs
Ground Control Points (GCPs) are established at corners and centers of forecasted imagery blocks, ensuring maximum accuracy. Accuracy of GCPs is ±1 m.
Retracing and Pegging of TPs
Turning Points (TPs) are retraced on the ground using a Total Survey Station, and pegs are installed for accurate alignment referencing.
DGPS Survey of TPs and Crossings
Mapped features include:
- Pipelines, TPs, IPs, GCPs, Crossings
- Roads, Highways, Canals, Power Lines, Water Bodies
Feature Extraction from Satellite Imagery
Existing data, including maps, tables, and satellite images, is verified for accuracy. Raster maps are scanned, digitized, and integrated with DGPS survey layers in GIS. Geocoding ensures correct spatial referencing, and data is published for client verification.
Preliminary Alignment
Preliminary alignments are placed on Google Maps to verify the corridor and TPs. DGPS surveys and stereo-pair DTM refine the alignment.
Satellite Image Processing and Ortho Photo Generation
Satellite images are processed to convert binary data into colored, usable images. PAN and multispectral images are merged and orthorectified using GCPs to correct terrain and sensor distortions. Orthoimages are applied to GIS-based 3D alignment.
Creating a DEM
DEM creation involves three key steps: epipolar image creation, image matching, and DEM geocoding. Stereo pair tools and epipolar 3D cursors extract precise elevation values. DEMs can be relative or absolute, georeferenced to ground coordinates.
DTM Overlay on Satellite Land Use
DTM elevation data is overlaid on 2D satellite images with a 750 m buffer for Civil 3D pipeline alignment.
Ground Surface Model
TIN models define the ground surface in Civil 3D. Pipeline centerline alignment, vertical profiles, and cross-sections create dynamic 3D design models.
Object Styles and Creating Alignments
Civil 3D object styles control display and annotation. Polylines through TPs are used to generate vertical and horizontal alignments. Cross-sections and corridors update automatically with alignment changes.
Extraction of Model
Civil 3D terrain and alignment models are extracted into infrastructure modellers to create 3D virtual pipeline visualizations.
2D and 3D Alignment Sheets
Final deliverables include 2D planimetry, 3D alignment sheets, and animated terrain models showing pipeline traces and construction-ready visualizations.
