Work Flow

GEOID not only gone through client’s Scope of work but also instils value addition on any project.

Collect AOI (Area of interest ) in KML or Shape Format & Permanent Bench Mark (if any) from any nearby Project or ORSAC PBM.

Flight Planning

• Pre-planning
• Import KML Mapping out driving route and ground control placement.
• Safety assessments and traffic management SRTM/Quarry DEM Terrain.

GCP

Without GCPs, combined errors of ten-plus degrees in a drone’s pitch or roll can introduce errors of tens of centimeters in the final survey.
Basically, absolute accuracy can be reined in from meters to centimeters with GCPs.

Used 75 Nos of GCP; preferable in Grid pattern to have most accurate Georeferenced data.
The GCPs were placed homogeneously in the area of interest.

Photogrammetry, image overlap, and camera settings

To get accurate and precise data on photogrammetry, acquired each image with a regular grid pattern from at least three positions with at least 75% frontal overlap (with respect to the flight direction) and at least 60% side overlap (between flying tracks).
The camera was maintained at a constant height over the terrain / object to ensure the desired Ground Sample Distance.

GSD

The distance between center points of each sample taken of the ground. Since we’re talking about digital photos, each sample is a pixel.
In simpler terms, the GSD is how big each pixel is on the ground.
In the present case, 2.5-3cm per pixel was taken.

Image capturing

Capturing images with in a regular grid pattern with 75% Frontal Overlap & 60% side overlap (between flying tracks). The camera was maintained at a nadir direction with a constant height over the terrain to ensure the desired GSD Survey statistics are outlined hereunder.