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18-Geom-B1 Digital Terrain Modelling: December 2015

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

  1. Question 1 Drivers of the DEM Sampling Interval
  2. Question 2 DTM vs DEM vs DSM
  3. Question 3 Definitions in Digital Terrain Modelling
  4. Question 4 Merits of DEM Data-Generation Methods
  5. Question 5 Regular Grid vs Irregular (TIN) Data Distribution
  6. Question 6 Steps to Create a TIN
  7. Question 7 DEM for Watershed and Floodplain Boundaries
  8. Question 8 Filtering vs Smoothing
  9. Question 9 Kriging for DEM Interpolation
  10. Question 10 Locating and Eliminating Blunders in a DEM
  11. Question 11 DEMs for Orthophotos and Volume Computation
  12. Question 12 DSM to Rectify Digital Satellite Imagery

Start with Question 1 →

Paper format: National Exams, December 2015 — 3 hours, closed book (an approved Casio or Sharp calculator permitted). TWELVE numbered questions constitute a complete paper; each is of varying value and the margin schedule totals 100 marks. Most answers are required in essay format, so clarity and organization are graded. All twelve questions are solved below for completeness.

Reference texts: Li, Zhu & Gold, Digital Terrain Modeling — Principles and Methodology (CRC Press, 2005); Maune (ed.), Digital Elevation Model Technologies and Applications: The DEM Users Manual (2nd ed., ASPRS, 2007); Wilson & Gallant, Terrain Analysis — Principles and Applications (Wiley, 2000); Wolf, Dewitt & Wilkinson, Elements of Photogrammetry with Applications in GIS (4th ed., McGraw-Hill); Natural Resources Canada High-Resolution DEM (HRDEM) and CDEM product specifications. Canadian datums throughout (NAD83(CSRS), CGVD2013).

Note: this December 2015 paper is the same twelve-question essay set as the December 2014 04-Geom-B1 exam, re-ordered and with one definition changed (Q3(e) asks for the contour interval where the 2014 paper asked for the interpolation method). The margin marks are internally consistent this year — every sub-part annotation matches its header weight and the schedule sums to 100.