GIS
Assigning a CRS versus transforming coordinates in GIS
Assigning a coordinate reference system tells software how existing numbers should be interpreted.
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THE DRONE COLLAB JOURNAL
Better drone maps start with better decisions.
Explore practical photogrammetry, GNSS, IMU, GIS and remote sensing methods. Technical explanations, worked examples and field checks for the people turning aerial photographs into usable maps.
1554 articles13 topics
Flight planning
Terrain-Following Capture for Coastal Settlement Corridors
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IMU & GNSS
Marking surveyed targets in images: the uncertainty inside a pixel
A surveyed target coordinate must be associated with the same physical location in each image.
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IMU & GNSS
Control point geometry: why distribution matters more than a count alone
Control points constrain a reconstruction through their geometry as well as their number.
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IMU & GNSS
Ground control and checkpoints: different roles in one project
Ground control observations participate in defining or adjusting the model, while checkpoints are withheld to evaluate its behavior independently.
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IMU & GNSS
Position covariance and confidence ellipses without false certainty
A covariance matrix describes uncertainty under an estimator model and includes correlations between coordinate components.
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IMU & GNSS
Dual antenna GNSS heading: what the baseline actually constrains
A dual antenna system can estimate the orientation of the baseline connecting its antennas from relative GNSS observations.
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IMU & GNSS
GPS time, UTC, and local time in a mapping timeline
GPS time, UTC, and a local civil time are different time representations.
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IMU & GNSS
EXIF geotags and corrected camera coordinates: keeping both histories
An image geotag is metadata associated with a photograph, not a complete navigation solution.
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IMU & GNSS
Interpolating a trajectory at image exposure times
Navigation records and camera exposures rarely occur at exactly the same instants.
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IMU & GNSS
Camera event marks: linking the exposure to the trajectory
A camera event mark records an electrical or software event that is intended to relate an image to navigation time.
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IMU & GNSS
Forward and backward PPK solutions as a consistency test
A forward solution estimates the trajectory in chronological order, while a backward solution processes observations in the opposite direction.
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IMU & GNSS
Preparing PPK observations without losing the evidence
Post processed kinematic positioning uses recorded observations rather than depending entirely on a live correction link.
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