GELE Photogrammetry & Cartography — Aerial Photography and Camera GeometryConcept Map

Concept

Camera Geometry and Optical Systems

Sub Concepts

• Focal length (f)
• Principal point
• Optical axis
• Nadir point
• Metric camera specifications

Relationship To Central

Foundation of photogrammetric measurement; defines how images are formed

Concept

Vertical Photography

Sub Concepts

• True vertical condition
• Principal point and nadir coincidence
• Flying height above terrain
• Mean ground elevation

Relationship To Central

Primary method for mapping; simplifies geometry through similar triangles

Concept

Photo Scale and Measurement

Sub Concepts

• Scale formula (f/H)
• Scale denominator
• Photo distance to ground distance conversion
• Scale variation over terrain

Relationship To Central

Core principle enabling ground distance extraction from photos

Concept

Ground Coverage and Area Calculation

Sub Concepts

• Photo format dimensions
• Ground side calculation
• Ground area coverage
• Area units conversion (m², ha, km²)

Relationship To Central

Determines survey efficiency and photo requirements

Concept

Flight Planning and Overlap

Sub Concepts

• Forward overlap (60%)
• Sidelap (30%)
• Air-base calculation
• Line spacing
• Exposure interval

Relationship To Central

Ensures complete stereo coverage and continuous mapping

Concept

Unit Conversion and Calculations

Sub Concepts

• Millimeters to meters
• Scale denominators
• Area conversions
• Distance scaling

Relationship To Central

Essential for practical problem solving in photogrammetry

Concept

Practical Applications in Philippine Surveying

Sub Concepts

• Cadastral mapping requirements
• Land classification surveys
• Infrastructure planning
• Environmental monitoring
• PRS92/WGS84 integration

Relationship To Central

Contextualizes photogrammetry in RA 4374, RA 8560, and PD 1529 framework

To

Photo Scale

From

Focal Length (f)

Strength

strong

Relationship

Focal length is the numerator in the scale equation; directly proportional to scale magnitude

To

Photo Scale

From

Flying Height (H)

Strength

strong

Relationship

Flying height is the denominator in scale equation; inversely proportional to scale—higher flight produces smaller scale

To

Ground Distance Conversion

From

Photo Scale

Strength

strong

Relationship

Scale denominator (S) is the multiplier to convert photo distances to ground distances

To

Photo Scale

From

Vertical Photography

Strength

strong

Relationship

Vertical condition ensures valid application of simple scale formula f/H; tilted photos require different geometric corrections

To

Ground Coverage

From

Photo Format (d)

Strength

strong

Relationship

Photo format dimension multiplied by scale denominator gives ground side; squared for area

To

Flight Planning

From

Ground Coverage

Strength

strong

Relationship

Area covered per photo determines number of photos needed; guides flight line planning and spacing

To

Flight Planning

From

Forward Overlap (60%)

Strength

strong

Relationship

Overlap percentage determines air-base spacing between consecutive exposures along flight line

To

Flight Planning

From

Sidelap (30%)

Strength

strong

Relationship

Sidelap percentage determines perpendicular line spacing; ensures continuous coverage between adjacent flight lines

To

Principal Point and Nadir

From

Camera Geometry

Strength

moderate

Relationship

For truly vertical photos, principal point coincides with nadir, simplifying ground projection calculations

To

Mean Ground Elevation

From

Flying Height above Terrain

Strength

moderate

Relationship

Average scale calculation uses mean ground elevation to determine effective flying height for scale computation

To

Photo Distance to Ground Distance

From

Unit Conversion

Strength

strong

Relationship

Photo measurements in millimeters converted to ground distances in meters using scale denominator; essential for accuracy

To

Survey Accuracy

From

Metric Camera Specifications

Strength

strong

Relationship

Known focal length and format dimensions provide foundation for all photogrammetric calculations

To

Aerial Photography Requirements

From

Philippine Surveying Standards (RA 4374, RA 8560, PD 1529)

Strength

moderate

Relationship

Regulatory framework defines accuracy standards and specifications for cadastral and engineering surveys using photogrammetry

To

Aerial Photography Data

From

PRS92/WGS84 Coordinate Systems

Strength

moderate

Relationship

Photogrammetric measurements must be integrated with geodetic coordinate systems for accurate geospatial referencing

To

Ground Distance between Exposures

From

Air-Base Calculation

Strength

strong

Relationship

Air-base is the ground distance between camera positions; determines overlap effectiveness and stereo base

To

60% Forward Overlap and 30% Sidelap

From

Stereo Coverage

Strength

strong

Relationship

Combined overlap percentages ensure every ground point is visible in at least two photos from different camera positions