We utilize multiple data sources for the preparation of geo-referenced vectorized base maps. These sources include the following:
- Existing hard copy maps (administrative maps, cadastral sheets etc.)
- High-resolution satellite imagery and aerial images
- Field survey mainly to validate the existing data and to collect landmarks
- In addition to spatial information, our surveyors also collect attribute information to make the base map more reliable and useful.
The base maps we create undergo a series of steps for development. Here's a quick look:
- Fixation of area of interest including demarcation of administrative boundaries
Scanning and mosaicking of the existing hardcopy maps
GCP collection to geo-reference the administrative maps and satellite imagery
Superimposition of scanned maps over Satellite Imagery
Field validation of the same mainly using DGPS to ensure accuracy
- Digitization of relevant layers from geo-referenced scanned maps including administrative layers like corporation/ municipality boundaries, ward boundaries etc.
- Extraction of spatial layers from the satellite imagery including roads, railways, water bodies and other relevant features.
- Ground-truthing to validate the prepared map via attribute data collection
- DGPS/ GPS survey to collect points of interest
- This is followed by integration of the field output for further enhancement of the base map.
So far, we have developed more than 150 base maps for town planning.