---
title: "Short note: Photogrammetry limitation and uses"
subject: "Surveying II"
chapter: 7
key: "semester_4/surveying_ii:photogrammetry-limitations-uses"
source: https://www.bctengineer.com/q/semester_4/surveying_ii/photogrammetry-limitations-uses
site: BCT Engineering
---

# Short note: Photogrammetry limitation and uses

Surveying II · Chapter 7: Photogrammetry and Remote Sensing

- Asked in: 2066 Magh (old course), 8 marks
- Video: [Advantages and Disadvantages of Photogrammetry](https://www.youtube.com/watch?v=S9IKLF0KtLw) — Photogrammetry Academic
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/surveying_ii/photogrammetry-limitations-uses
- Whole chapter: https://www.bctengineer.com/md/semester_4/surveying_ii/chapter-7

## Question

Write a short note on photogrammetry, its limitation and uses.

## Short answer

Photogrammetry obtains measurements and maps from photographs. Uses include topographic mapping, engineering site selection, cadastral surveys and disaster management. Limitations include high cost, weather dependency, need for ground control, and inability to see beneath dense vegetation or buildings.

## Answer

**Photogrammetry** is the science and art of obtaining reliable measurements, maps and three-dimensional information of objects and terrain from photographs. Aerial photogrammetry uses photographs taken from aircraft or drones, and close-range photogrammetry uses ground-based cameras.

```text
   Camera stations O1 -------- O2
        \                      /
         \    overlap area    /
          \__________________/
              ground  -> 3D model -> map
```

#### Basic steps
1. Plan the flight and establish ground control.
2. Take overlapping photos (60 % end lap, 25–30 % side lap).
3. Process the photos, orient the stereo pairs, and measure.
4. Produce maps, DEMs, orthophotos or coordinates.

#### Uses
- Topographic, planimetric and contour maps of large areas.
- Engineering projects: route location, site selection for dams, bridges and airports.
- Earthwork volume and cross-section measurement.
- Cadastral surveys, land use planning and urban planning.
- Geology, forestry, agriculture and archaeology.
- Disaster management: flood and landslide mapping, damage assessment.
- Close-range work: structural deformation, monuments, accident reconstruction.

#### Limitations
- Costly equipment, aircraft and trained personnel; uneconomical for small areas.
- Weather dependent: clouds, haze and shadow affect photo quality.
- Ground control is still needed, and field verification of names and details is necessary.
- Dense vegetation, shadows and tall buildings hide the ground; small details may not be visible.
- Accuracy depends on scale, camera quality, tilt and relief displacement; processing needs skill.
- Boundaries and underground features cannot be seen.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Photogrammetry is:
   A. Measuring with total station
   B. Obtaining measurements, maps and 3D information from photographs
   C. GPS positioning
   D. Soil mapping by borehole
   Answer: B. It covers aerial and close-range work. (Key point: Definition)

2. The overlaps used are:
   A. 25% end lap, 60% side lap
   B. 100% both
   C. 10% both
   D. 60% end lap, 25-30% side lap
   Answer: D. Needed for stereo and coverage. (Key point: Overlaps)

3. Which is a limitation?
   A. Works through clouds
   B. Weather dependent; costly and uneconomical for small areas
   C. Needs no ground control
   D. Sees underground features
   Answer: B. Clouds, haze and shadow affect quality; ground control and field verification are needed. (Key point: Limitations)

4. Accuracy depends on:
   A. Only colour
   B. Only time of day
   C. Only film size
   D. Scale, camera quality, tilt, relief displacement
   Answer: D. These factors affect measurement. (Key point: Accuracy factors)

## Related in Surveying II

- [Short note: Photo scale, photogrammetry uses](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aphoto-scale-photogrammetry-uses) — Surveying II, chapter 7
- [Short note: Importance and uses of photogrammetry](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aphotogrammetry-importance-uses) — Surveying II, chapter 7