Week 12: S Flashcards
(20 cards)
What is photogrammetry?
Obtaining information from aerial and terrestrial photos. (From aircrafts/satellites)
Why do we do photogrammetry?
To map land. Even to create a 3D model.
Pros and cons of photogrammetry?
Pro - Good maps.
Con - Very costly for the aircraft and camera.
Why do you need 2 photos, of the same area from 2 different positions.
Only way to accurately gauge distance.
What is the overarching process involved?
Stereo photogrammetry.
What do we get from photogrammetry?
Aerial photos. Topographic maps (1:50 000). Orthophoto (1:10 000) - A combination of the first two where parallax is removed (can make measurements).
When do we apply photogrammetry?
Google Earth, drones, imaging using Lidar of structures.
What is remote sensing?
Data capture from satellites.
Pros and cons of remote sensing?
Pro - High resolution. Can cover a lot of ground quickly. Can resurvey huge areas every week.
Con - Very expensive. Complex and very specialised.
What is required for remote sensing?
Energy source (the sun).
When is remote sensing applied?
Cartographic (to some extent). Agricultural. Sea surface and shallow subsea. Environmental uses. Disaster assessment and response. Military.
What is Lidar?
Light detection and ranging. (short distances) Measure distances. (Scan the Notre Dam).
How is Lidar applied?
Classify
What is GIS? (Or GISc)
Geographic Information System. (science) A system for input, storage, manipulation and output of geographic (spatial) data.
What is GIS used for?
Data collection and input. Data storage and easy retrieval. Data analysis. Output and display.
To make decisions using spatial entities. Or analyse some data.
Components involved with GIS?
People -> Data ->
Types of data in a GIS?
Spatial data (Position). Raster - Stored as pixels. Vector - (Coordinates) Stored as points, lines and polygons.
Attribute data (Text).
What is stored in a relational database and a geodatabase?
Relational: Text data.
Geodatabase: Positions.
Must be linked in a database.
Who uses GIS?
Planners, Engineers, Municipalities, Banks and Natural resource managers.
Don’t just study slides. Also detailed notes. Lecture on coordinates is very important. Know what a join and a polar is. You could be asked calculations. Know prac as well.
You got this.
Surveying 30%
Engineering Geology 30%
Geology 40%.
