18-Geom-A7 Geospatial Information Systems · May 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
National Exams — May 2014 — 04-Geom-A7 Geospatial Information Systems. Closed-book; no calculator permitted. Format: twenty-three short-answer questions of equal value (5 marks each); a candidate answers any twenty, but all twenty-three are solved in full below. Datum and coordinate conventions follow the Canadian spatial reference framework — NAD83(CSRS) horizontally and CGVD2013 vertically.
Reference texts: P. A. Longley, M. F. Goodchild, D. J. Maguire & D. W. Rhind, Geographic Information Systems and Science (4th ed., Wiley, 2015); P. Bolstad, GIS Fundamentals: A First Text on Geographic Information Systems (6th ed., XanEdu, 2019); P. A. Burrough, R. A. McDonnell & C. D. Lloyd, Principles of Geographical Information Systems (3rd ed., Oxford, 2015); M. Worboys & M. Duckham, GIS: A Computing Perspective (2nd ed., CRC, 2004); ISO 19115 Geographic information — Metadata.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
A DBMS (Database Management System) is the software that stores, organizes, retrieves and maintains data in a structured, controlled way — providing data integrity, security, concurrent multi-user access, backup/recovery and a query language (SQL) — independent of any single application. In a GIS the DBMS manages the attribute tables and, in a spatial DBMS, the feature geometry as well, so that spatial and non-spatial data live together in one managed store (a geodatabase). It lets many users query and edit a shared dataset simultaneously without corruption, enforces integrity and topology rules, supports joins and relational queries linking features to their attributes, and, through spatial SQL functions, executes spatial queries (intersects, within, buffer) directly in the database. This separation of data management from the GIS front-end is what allows enterprise GIS to scale to large, shared, versioned datasets. Two examples of DBMSs used in GIS: PostgreSQL with the PostGIS spatial extension (open-source, widely used for spatial databases) and Oracle Database with Oracle Spatial. Other common examples include Microsoft SQL Server (with its spatial types) and, for smaller single-user work, the Esri file geodatabase and SpatiaLite.
