Certified Photogrammetrist Quality Control & Standards in Photogrammetry

Question 1

What does the ASPRS 2014 standard use instead of the traditional NMAS 90% circular error to define accuracy?

Accepted Answer

RMSE-based accuracy with separate thresholds for horizontal (RMSEx, RMSEy) and vertical (RMSEz) components

Answer

Probable error (PE50)

Answer

Standard deviation of ground control residuals only

Answer

Maximum allowable error for any single check point

Question 2

What is the minimum number of independent check points recommended by ASPRS 2014 for a small project area (< 500 km²)?

Accepted Answer

At least 20 well-distributed independent check points

Answer

5 check points

Answer

20 check points

Answer

100 check points per map sheet

Question 3

What is 'QA/QC' in the context of a photogrammetric mapping project?

Accepted Answer

Quality Assurance (process controls) and Quality Control (product inspection and testing) to ensure deliverables meet specifications

Answer

Quick Acquisition / Quality Collection — field data collection protocols

Answer

Quantitative Analysis / Qualitative Calibration of sensor data

Answer

The flight plan review process before data acquisition

Question 4

What is a 'metadata report' required to accompany photogrammetric deliverables?

Accepted Answer

Documentation describing data acquisition parameters, processing methods, datum/projection, accuracy, and data quality information

Answer

A financial invoice detailing all project costs

Answer

A list of all software licenses used in production

Answer

A photographic log of the camera operator's activities

Question 5

What is 'vertical datum' and why is it critical in photogrammetric elevation products?

Accepted Answer

The reference surface (e.g., NAVD 88, NGVD 29, ellipsoid) to which all elevations are referenced, determining how heights interoperate with other datasets

Answer

The minimum flight altitude allowed by aviation regulations

Answer

The maximum allowable vertical error in the DEM product

Answer

The elevation of the base station used for GPS differential correction

Question 6

What is 'data completeness' as a dimension of geospatial data quality?

Accepted Answer

The degree to which all required features and attributes are present and correctly represented in the dataset

Answer

The percentage of image pixels with valid radiometric values

Answer

The number of check points used to assess accuracy

Answer

The ratio of collected mass points to the project area