What is a DGPS survey?
Differential Global Positioning System (DGPS) surveying uses a fixed base station of known coordinates together with a roving receiver to correct ordinary GPS error. This brings positional accuracy from several metres down to the sub-metre or centimetre level.
Where it is used
- Forest boundary demarcation and land-schedule preparation
- Generation of KML / SHP files for the PARIVESH portal
- Georeferencing of toposheets and cadastral maps
- Route and alignment surveys for roads, transmission lines and pipelines
- Area computation for Compensatory Afforestation and diversion proposals
Why precision matters
In forest and environmental clearance, the exact area and boundary of the land being diverted decides the Compensatory Afforestation, the Net Present Value and the legal extent of the approval. Even small errors can trigger objections, re-surveys and long delays. Accurate DGPS data makes a proposal defensible and speeds approval.
Key takeaways
- DGPS corrects GPS error to sub-metre / centimetre accuracy
- Essential for the KML / SHP files required on PARIVESH
- Underpins land schedules, alignments and area computation
- Precision reduces objections and approval delays