Podcast
Questions and Answers
Which component is NOT a part of the flight planning process?
Which component is NOT a part of the flight planning process?
Flight planning is only necessary for large-scale aerial missions.
Flight planning is only necessary for large-scale aerial missions.
False
List two key factors that must be determined during flight planning.
List two key factors that must be determined during flight planning.
Photographic end lap and side lap, Purpose of the photography
A successful flight plan reduces the risk of _____ which can lead to costly project delays.
A successful flight plan reduces the risk of _____ which can lead to costly project delays.
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Match the following flight planning procedures with their descriptions:
Match the following flight planning procedures with their descriptions:
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What is the primary use of shadows in aerial photography?
What is the primary use of shadows in aerial photography?
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Pilot navigation can solely rely on identifiable ground features for proper flight coverage.
Pilot navigation can solely rely on identifiable ground features for proper flight coverage.
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What ideally aligns flight lines in rectangular areas?
What ideally aligns flight lines in rectangular areas?
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A flight map is often based on __________ maps or small-scale aerial photos of the area.
A flight map is often based on __________ maps or small-scale aerial photos of the area.
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Match the terms with their definitions:
Match the terms with their definitions:
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Which of the following is NOT a function of ground control in photogrammetry?
Which of the following is NOT a function of ground control in photogrammetry?
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Templates used in flight planning can help decide where exposure stations should be placed.
Templates used in flight planning can help decide where exposure stations should be placed.
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What does GCP stand for in aerial photogrammetry?
What does GCP stand for in aerial photogrammetry?
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What does a smaller Ground Sampling Distance (GSD) indicate?
What does a smaller Ground Sampling Distance (GSD) indicate?
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Ground Control Points (GCPs) are only measured after the drone flight.
Ground Control Points (GCPs) are only measured after the drone flight.
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What is the purpose of overlapping images during aerial photography?
What is the purpose of overlapping images during aerial photography?
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A flight plan may include goals such as desired accuracy, flight height, and _______ to ensure effective photography.
A flight plan may include goals such as desired accuracy, flight height, and _______ to ensure effective photography.
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Match the following components with their functions in flight planning:
Match the following components with their functions in flight planning:
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Which device can reduce the need for Ground Control Points during drone flights?
Which device can reduce the need for Ground Control Points during drone flights?
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To achieve centimeter accuracy, using GCPs is essential.
To achieve centimeter accuracy, using GCPs is essential.
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What key factors should be taken into account when planning a drone flight?
What key factors should be taken into account when planning a drone flight?
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Study Notes
Digital Photogrammetry (GEOM 2020) - Week 5: Planning a Mapping Project: Flight & GCP
- Course: Digital Photogrammetry (GEOM 2020)
- Department: Geomatics Engineering and Land Management
- Week: 5
- Lecturer: Dr O.O Aladejana
- Topic: Planning a Mapping Project (Flight & GCP)
Outline
- Flight Planning
- Planning the Ground Control
- Selecting Instruments
- Estimating Costs and Delivery Schedules
Flight Planning
- Purpose: For effective photography, the mission must be meticulously planned and executed according to the flight plan
- Components: A flight (navigation) map is essential, showing where aerial photographs are to be taken along with key parameters
- Importance: Critical to successful photogrammetric projects, ensures proper specifications (camera, scale, flying height, overlap, tilt, etc.) and avoids costly re-flights and delays
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Procedures:
- Photographic end lap and side lap
- Purpose of the photography
- Photo scale
- Flying height
- Ground coverage
- Weather conditions
- Season of the year
- Flight map
Photographic Overlap and Side Lap
- Requirement: Aerial photo projects for most mapping and image analysis require a series of exposures made along multiple flight lines
- Importance: Stereoscopic coverage of the entire site, essential for avoiding missing bits
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Types:
- Overlap: In the line of flight (needed for parallax)
- Sidelap: Between adjacent flights (to avoid missing bits)
Flightline of Aerial Photography
- Stereoscopic model: The overlap of photographs allows for the creation of a stereoscopic model, recording terrain on three successive photographs
- Altitude: The altitude above ground level is a factor in the accuracy of the stereoscopic model
- Coverage: The coverage of each photograph is crucial for comprehensive terrain recording
Purpose of Photography
- Metric vs. Pictorial: Metric qualities are needed for topographic mapping and quantitative measurements, while pictorial qualities are essential for qualitative analysis and visualization
- Uses (Metric): High precision for surveying, creating accurate maps, and photogrammetric analysis
- Uses (Pictorial): Suitable for photographic interpretation, orthophotos, aerial mosaics, and photomaps
- Cameras (Metric): Calibrated cameras (known focal length, principal point, lens distortion, sensor alignment, image resolution, and scaling factors) are needed for high-precision tasks
- Cameras (Pictorial): Wide-angle or super-wide-angle cameras (short focal lengths) are preferred for tasks like photographic interpretation
B/H' Ratio
- Definition: The ratio of the air base (B) of overlapping photos to the average flying height (H').
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Impact of Larger Ratio:
- Greater intersection angles between light rays
- Better accuracy in determining points on the ground
-
Impact of Lower Ratio:
- Lower flying heights, smaller parallactic angle
- Less accurate for mapping
- Importance: Understanding B/H' is crucial for accurate mapping.
Photo Scale
- Importance: An important variable in planning aerial photography, generally fixed by project requirements
- Topographic Mapping: Dictated by the map's required scale and/or horizontal and vertical accuracy
- Photo Interpretation/Mosaics: The ability to clearly see the smallest important ground objects is crucial when preparing orthophotos or mosaics
Deriving Photo Scale
- Example (Highway Markings): A project needing to study highway centerlines requires a particular photo scale to capture the necessary detail. Calculations using given values (actual width, high-resolution film, and the smallest resolvable object size) will determine the minimum required scale
Flying Height
- Focal length and average photo scale: The flying height is determined automatically (fixed) according to the selected camera focal length and required average photo scale
- Terrain elevations: The average elevation of the terrain is important to account for in accurate calculations
Ground Coverage
- Neat model: The stereoscopic area between adjacent principal points, extending out sideways to the middle of the side lap
- Dimensions: The neat model has a width of B and a breadth of W, representing the approximate area of each stereopair
Weather Conditions
- Ideal: Clear skies, less than 10% cloud cover, overcast weather (helpful for large-scale photos)
- Unsuitable: Haze, smog, dust, smoke, high winds, and image motion (difficult for mapping, best to avoid)
Season of the Year
- Deciduous trees: Photography should be done when deciduous trees are bare (late fall/early spring) to prevent obscuring ground detail
- Forestry: Photography may require trees to be in full leaf during specific seasons
- Snow: Not ideal for photography since it obscures details; however, light snow can sometimes aid identification in areas with trees -Sun's altitude: Best times for aerial photography are when the sun is above 30° to minimize long shadows
Flight Map
- Boundaries and lines: A flight map shows the project boundaries and flight lines the pilot must follow for proper coverage
- Basis: Often based on topographic maps or small-scale, aerial photos of the area
- Navigation: Pilots use identifiable ground features for accurate coverage; airborne GPS can also be used for predefined flight lines
Flight Line Orientation
- Rectangular areas: North-South or East-West alignment is ideal for efficient mapping
- Irregular areas: Flight lines can be aligned parallel to project boundaries for efficiency
- Templates: Transparent templates help show blocks of neat models are placed over maps to plan the most economical coverage
Planning the Ground Control
- Photogrammetric control: Involves points with known positions and references with identified images in photographs
- Aerial photogrammetry: Ground control relates aerial photographs to the ground and is essential across all phases
- GPS/INS: Aircraft can serve as control for photogrammetric surveys (measuring camera positions and attitudes during acquisition)
Ground Control Points (GCPs)
- Definition: Points with known positions in a reference coordinate system, whose images are identifiable in photographs
-
Use:
- Georeferencing products
- Accurately determining intrinsic & extrinsic parameters
- Improved accuracy of finished photogrammetric products
- Types: Horizontal Control Points, Vertical Control Points, and Full Control Points
- Measurement: Usually measured using GPS or other terrestrial surveying before or after the flight
Drone Flight Planning: Principles and Practices
- Topics: On drones and what they can do, reasons for Planning (The 'Why,' 'How,' and 'What,' some points on Planning), Software, and examples regarding planning
Cost Estimation and Delivery Schedules
- Materials, labor, overhead factors considered in cost estimation
- Effort categories: Labor, materials, overhead, and profit
Delivery Schedule
- Basis: Project hours, available instruments/workstations, trained personnel, ongoing work, and client urgency influence scheduling each project phase
Drone Flight Path Design and Accuracy
- Area of Interest (AOI): Drone flight plans focus more than just the AOI but also consider flight altitude, forward overlap, and side overlap
- Altitude: Higher altitude means more area covered, but less detail (and vice-versa)
- Ground Sampling Distance (GSD): A measure of the accuracy of the image; smaller GSD equates to a more detailed view of the area
Drone Flight Plan Design and GCPs
- Overlaps: Images need overlaps in both frontal (between flight lines) and side directions (at the flight line edges)
- GCPs: Needed to register/relate the models to real-world coordinates for creating accurate 3D models
Summary/Summary Tables
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Description
Test your knowledge of flight planning processes and procedures. This quiz covers key factors to consider during planning and identifies components essential for successful missions. Perfect for aviation students and professionals alike.
