Tag Archive: digital terrain model

3D feature extraction services

3D shapes have been functional in many fields, such as 3D City modelling, Terrain Visualization, industrial design, education, animation entertainment and preservation of historical sites, etc. Feature extraction of 3D shapes is an important branch of Geographical Information Systems using the advanced technologies like Digital Photogrammetry, LiDAR Data processing and pattern recognition, attracting more responsiveness from many technocrats. 2D feature mapping shows only horizontal features on a planar surface, without elevation contours to depict the terrain, whereas in 3D topographic mapping contour and elevations are vital parts. More importantly combination of Planimetric/Topographic Mapping is a depiction of the Earth surface features in 3D means and used for geospatial analysis and modeling.

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SBL’s 2D/3D Feature Extraction in-house expertise qualifies us to capture data from small to large scale stereo models and generate high precision digital topographic maps. SBL 3D feature extraction services provides accurate digital planimetric feature extraction for cartography mapping and 3D topo mapping by extracting surface features like railroads, buildings, hydrological features, vegetation, etc., with proper coding and symbology.
     Viewing the features extracted from the above methods and get superimposed on the 3-dimensional digital aerial photograph, ensures that editing and collection time is accurate and complete.
SBL’s ability to create customized databases and cartographic map representations is useful in meeting any specification or software format.

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The benefit of 3D features is the value-added geospatial information that can be derived from high resolution stereo images and hi-density point cloud data. This comprises three specific data products, not exclusively, Digital Orthophoto, digital terrain models and 3D vector data. Digital Orthophoto have turn out to be a standard constituent of base map data, and can be used for accuracy assessment, 2D vector digitizing and update, change detection and a number of other applications. 

AREAS INFLUENCED BY 3D APPLICATIONS:
     •Long Range Planning
     •BIM 
     •Utility Network Designing
     •Plant/Facility Planning & Management
     •Roadway Design
     •Utility Management
     •Landfill/Quarry Management
     •Topographic Surveys
     •Volumetric/Quantity Calculations

Rail Utility mapping and digital asset preparation from 3D point clouds

Light Detection And Ranging (LiDAR) technology provides most accurate input data source for utility mapping. High accuracy, operation from multiple platforms, and ability to survey through tunnels makes this technology unique for rail utilities. Lidar data can be acquired in discrete patches and later register to get a complete 3D point cloud of the rail corridor. Hence data handling and processing will be faster when comparing with other technologies. Another added advantage is that its feasibility to get minute details of the intricate features. Ability to collect RGB values along with intensity makes this technology most relevant for 3D model preparations. This will be of great help to rail engineering, designing and maintenance and constructing organizations. So survey grade spatial information can be collected in a faster pace with this kind of data. More over this data can be processes in multiple software platforms like Auto CAD, Leica Cyclone, Terra, Micro station and combination of these.

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Digital rail asset mapping

The mail application of lidar survey in rail utility mapping area

  • Condition assessment of tracks and switches
  • Digital rail asset register preparation
  • Signage management
  • Vegetation encroachment monitoring
  • Corridor monitoring
  • Corridor design
  • Corridor maintenance
  • Kinetic monitoring

Sample Gantry

Sample Gantry

Rail right of way area is an asset intensive corridor. So mapping these corridors is labor intensive. SBL has got the technical capabilities to map, capture features and model them in a 3D environment for various design and maintenance activities. In a recent project SBL geo spatial team has collected an exhaustive list of more than 100 features related to rail assets. These are ranging from base structures to huge bridges. Presentation of output files in various 3D models pertaining to rail assets was one of the peculiarities of the project. SBL has prepared the data in 3D wire face model, 3D surface model, MX GENIO format as well as in lexica true view formats. Initially all the features were captured as wire frames and later converted to surface models. A digital terrain model of the area has been created by classifying the data to ground and non ground categories. Trimming adjustment with digital terrain models were performed to bring the features to ground level and to obtain accurate height of the features.

Sample electrical structure

Sample electrical structure

Challenges of using lidar data in rail corridor mapping are a). Possibility of features missing due to low intensity of the point clouds, b). Masking of the features due to presence of debris, c). Blockage of features due to presences of temporary articles present over the area and d). Registration related issues.

Sample over bridge

Sample over bridge

Rail operators are benefited in using such kind of data due to

  • It provides a complete digital record of all assets
  • Change detection is very easy
  • Encroachment of vegetation, unauthorized occupation and missing of features can be monitored
  • Condition assessment is very easy
  • Standard maintenance programme can be implemented and managed effectively.
  • Alternate and optimal routes can be established for new tracks and yards
  • Prefeasibility studies will became easy

GeoSpatial Scientific back up to Vastu Shastra

In a recent study, SBL has provided scientific back up to Vastu Shastra. Vastu shastra deals with the ancient Hindu beliefs in architecture. According to this school of thought prosperity of the house hold depends on its slope of the land and directional alignment of that location on the surface of the earth.In a similar way prosperity of the country also depends on its elevation orientation and position on the surface of the earth. In this context SBL has assisted a research study by Vastuvidya Gurukulam by analyzing elevation data of 50 countries.The digital terrain model generated through Shuttle Radar Topographical Mapping (SRTM) were analyzed for all these 50 countries and presented in the form of ready to print maps. Care has taken to see a true representation of the rich and poor counties and countries lies north and south of equator. In a similar way population density and per capita income of these 50 counties analyzed for establishing a correlation between these three entities and finally to related with other vastu vidya practices. So a geospatial data base has created for these 50 countries along with cartographic representations whereby spatial variation of elevation, population density and per capita income of all these countries were established.

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