Objectives

The primary objective of this tender is to appoint a service provider capable of supplying high-resolution digital colour aerial imagery with a ground sample distance (GSD) of 0.25 meters in Swellendam. The imagery will support the Chief Directorate: National Geospatial Information (NGI) in their mapping and geospatial data production programs, ensuring accurate, radiometrically and geometrically calibrated data suitable for photogrammetric and GIS applications.

Scope

The scope encompasses the acquisition of digital aerial imagery using advanced sensor systems, including:

• Use of large format digital photogrammetric cameras mounted on airborne platforms.
• Simultaneous capture of panchromatic and multispectral (RGB and NIR) imagery.
• Integration with GNSS/INS systems for precise exterior orientation data.
• Pre- and post-acquisition processing, calibration, and quality control.
• Delivery of processed, orthorectified, and radiometrically consistent imagery, along with comprehensive reports and metadata.

The acquisition must cover the designated area with specified overlaps, flight lines, and within the stipulated timeframes, ensuring data meets the technical and quality standards set by NGI.

Technical Requirements

The technical specifications include, but are not limited to:

• Sensor System: Large format digital photogrammetric cameras with true nadir and oblique capabilities, separate channels for multispectral bands, and calibration certificates.
• Image Resolution & Quality: Minimum GSD of 0.25m, 12-bit radiometric resolution, and high geometric accuracy (within 25% of pixel size).
• Sensor Calibration & Testing: Calibration certificates, boresight calibration, and operational tests with specified accuracy thresholds.
• GNSS/INS Integration: Use of IGS-approved GNSS antennas, IMU systems with specified post-processed accuracy, and proper registration and survey of antenna positions.
• Flight Planning & Acquisition: Proper flight line design, overlaps (forward 55-65%, sidelap 25%), minimal tilt and crab, and appropriate flying times considering solar altitude.
• Post-Acquisition Processing: Radiometric and geometric correction, image compression (TIFF with JPEG Q=3), and generation of metadata files.
• Quality Control & Validation: Operational tests, accuracy assessments, and detailed reporting on positioning, processing, and imagery quality.

Skills Requirements

The service provider must demonstrate expertise in:

• Operating large format digital photogrammetric cameras and sensor calibration procedures.
• Planning and executing aerial surveys with precise flight line design and overlap specifications.
• Integrating GNSS/INS systems for accurate exterior orientation data collection and processing.
• Processing and calibrating digital imagery, including radiometric and geometric corrections.
• Performing boresight calibration, aerial triangulation, and quality assurance of geospatial data.
• Producing comprehensive technical reports, including flight plans, processing summaries, and validation results.
• Managing data labelling, storage, and delivery in accordance with specified formats and standards.