ASPRS Certified Mapping Scientist / Photogrammetrist (Remote Sensing, Lidar)

USA · American Society for Photogrammetry and Remote Sensing · professional · unverified source

27practice questions written to this syllabus
2subjects

Format

Unverified. Experience review and written exam by specialty (remote sensing, lidar, photogrammetry, GIS/LIS).

Sections

Over the years

Unverified. A recognised credential for forest remote-sensing and LiDAR specialists.

Official source: https://www.asprs.org/

Subjects this exam draws on

Remote Sensing & Photogrammetry for Forestry15 questionsForest GIS, GNSS & LiDAR Analytics12 questions

Five practice questions, worked

Original questions written to this exam's published syllabus and pattern. Not past papers.

1. Using Wien's displacement law, a flaming fire at 1,000 K emits most strongly near:

  1. 0.5 µm
  2. 10 µm
  3. 2.9 µm
  4. 29 µm
Answer and working

C. 2.9 µm

λmax ≈ 2898 ÷ T = 2898 ÷ 1000 = 2.9 µm, in the middle infrared; the Earth at 300 K peaks near 10 µm.

Remote Sensing & Photogrammetry for Forestry · Electromagnetic spectrum and spectral signatures of vegetation

2. The horizontal errors of four GNSS check points are 1, 2, 2 and 3 m. What is the RMSE?

  1. 2.00 m
  2. 2.12 m
  3. 4.50 m
  4. 1.50 m
Answer and working

B. 2.12 m

RMSE = √((1 + 4 + 4 + 9) ÷ 4) = √4.5 = 2.12 m. 2.00 is the mean error; 4.50 is the mean squared error before the square root.

Forest GIS, GNSS & LiDAR Analytics · GNSS data collection and accuracy

3. Of 100 reference forest points, 90 are mapped as forest. The map shows 95 forest points, of which those 90 are truly forest. What are producer's and user's accuracy for forest?

  1. 94.7% and 90%
  2. 90% and 90%
  3. 90% and 94.7%
  4. 10% and 5.3%
Answer and working

C. 90% and 94.7%

Producer's = 90 ÷ 100 = 90%; user's = 90 ÷ 95 = 94.7%.

Remote Sensing & Photogrammetry for Forestry · Image classification: supervised and unsupervised; accuracy assessment

4. How does a full-waveform LiDAR system differ from a discrete-return system?

  1. It records only the first return from each pulse
  2. It uses a continuous beam rather than pulses
  3. It digitises the whole returned energy profile
  4. It measures colour as well as range
Answer and working

C. It digitises the whole returned energy profile

Full-waveform systems record the complete return signal, from which returns can be extracted later. Discrete systems store a few returns per pulse; continuous-beam phase measurement is typical of some terrestrial scanners.

Forest GIS, GNSS & LiDAR Analytics · Airborne LiDAR: point clouds, canopy height models

5. Active-fire detections are not a measure of burned area because they:

  1. Are always larger than the fire
  2. Use radar and miss smoke
  3. Are mapped at 1 m
  4. Record only fires burning at overpass
Answer and working

D. Record only fires burning at overpass

They miss fires under cloud, under canopy and between overpasses.

Remote Sensing & Photogrammetry for Forestry · Fire detection and burned-area mapping

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