Quality Control & Standards in Photogrammetry Flashcards

What does 'logical consistency' mean in geospatial data quality standards (ISO 19157)?

Answer: The degree to which a dataset conforms to its data model rules, including topological correctness and no invalid geometries

Logical consistency (ISO 19157) measures adherence to the data model's rules—such as polygon closure, no slivers, proper topology, and valid attribute values—independent of real-world accuracy.

In photogrammetric production, what is a 'calibration certificate' for a metric camera?

Answer: A laboratory report documenting the camera's interior orientation parameters (principal distance, principal point, lens distortion) determined by calibration

A calibration certificate documents the metric camera's interior orientation parameters—principal distance, principal point location, radial and decentering distortion—determined through laboratory calibration, essential for accurate photogrammetric processing.

What is a 'flight report' in aerial photogrammetry production?

Answer: Documentation recording flight line numbers, photo numbers, exposure stations, weather conditions, and quality observations during data acquisition

A flight report documents all relevant information about the data acquisition flight—including flight lines, photo numbers, GPS positions, weather conditions, and any anomalies—supporting project documentation and quality review.

What is 'stereo compilation QC' (quality control) typically checking for?

Answer: Feature completeness, geometric accuracy, attribution correctness, edge match quality, and adherence to project specifications

Stereo compilation QC reviews the compiled map features for completeness, geometric accuracy relative to the imagery, correct attribution, seamless edge matching between models, and conformance to the project's feature and accuracy specifications.

What does 'positional accuracy' mean in the ASPRS/FGDC standards context?

Answer: The closeness of the reported positions of features to their true positions on the Earth's surface

Positional accuracy (per ASPRS/FGDC) is the closeness of the reported coordinates of geographic features to their true positions, typically measured by RMSE against independently surveyed check points.

What is the purpose of 'independent QC' (third-party accuracy testing) in photogrammetric projects?

Answer: To provide an unbiased assessment of accuracy by an organization not involved in data production

Independent QC uses a third party not involved in production to collect and analyze check points, providing an unbiased accuracy assessment free from the production organization's potential self-reporting bias.