Ground Control for Mapping
The photogrammetric process for creating accurate mapping from aerial
imagery relies fundamentally on accurate ground control. Terrasurv has
performed ground control surveys in all 50 states and internationally for
projects ranging in size from a few acres to over 20,000 sq miles, and for a
variety of scales from 3 cm GSD to 1 m and greater.
LiDAR projects require both accurate ground control points (GCP) and
checkpoints (CP) to verify the accuracy of the delivered product. Terrasurv has
extensive experience establishing ground control for Lidar in an accurate and
economical manner for a variety of clients including numerous large USGS 3DEP
projects in both urban and remote areas.
Mapping control surveys are typically performed using Real Time methods
including RTK over cell, using a Virtual Reference Station (VRS) network, or
Trimble Real Time eXtended (RTX) methodologies.
Project: A LiDAR project was contracted for Post-Harvey mapping of several
areas in Texas.
Control Points (GCP) were surveyed:
Check Points (NVA) were surveyed:
(VVA) checkpoints (non-woods) were surveyed:
And 50 woods
(VVA-F) checkpoints were surveyed: