GEOG 328 Final Unit / Exam Prep Flashcards
What is a Binary model? What is it most commonly used for?
A Binary model is a model which presents explicit data, generally does not include a suitability scale but rather denotes suitable/unsuitable.
Uses a Boolean output 1 (yes, suitable) or 0 (no, unsuitable)
Binary modelling is generally used for when criteria must absolutely be met.
Commonly used for siting analysis
Example: siting a new school
What does Map calibration consist of for multi-criteria modelling
Binary - apply thresholds: exclude (0), include (1)
Multiple categories - Apply thresholds: high, medium, low (figure out levels of acceptance)
Range from 0-1 (or 100) - Linear / function
What does layer combination mean with regards to Multi-criteria modelling?
Combining the quantitative variables into one layer
What does Weighted Criteria Mean with regards to Multi-criteria Modelling?
The process whereby each input can be weighted according to its importance or its percent influence.
What does “constrain” refer to with regards to multi-criteria modelling?
It removes areas that should be excluded - keeps the output from looking strange.
e.g. Beetle infestations don’t occur in water/human illness does not occur where population density is 0.
What is a model?
A model is a representation of the real world.
What is a Spatial Model?
A spatial model is a representation of some phenomena and incorporates spatial data and relationships
What steps do you need to do before modelling?
Before modelling, data must be calibrated, layers of data integrated and logical/spatial constraints applied.
Before performing multi-criteria spatial modelling what must be done with the data?
For multi-criteria spatial modelling the data must be calibrated, layered, and constrained to aid in guiding the problem solving and analysis.
What is terrain?
Terrain - Also know as “relief”, this is the third dimension (elevation) of the land surface. The “lie of the land”.
How is terrain Expressed?
Expressed as elevation, slope, and aspect.
What does Terrain influence?
Influences climate, water, and water flow.
What is Bathymetry?
Underwater terrain.
How is Digital terrain surface modelling achieved?
Elevation points are used to create models of terrain.
T?F - Both DEM and TIN (triangulated irregular network) are considered to be digital elevation models?
TRUE
Of DEM and Tin, Which is a Raster and which a Vector?
DEM is used to refer to raster models.
Tin is used to refer to vector models.
What are some methods for obtaining elevation data to create DEM’s
Lidar-light detecting and ranging
Stereo photogrammetry from aerial surveys
Multi-view stereo applied to aerial photography.
Interferometry from radar data.
Real time kinematic gps
Topographic maps
Theodolite or total station
Doppler radar
Surveying and mapping drones range imaging.
What are some problems with Ground survey and GPS?
It is - expensive, time consuming, not viable over large areas
Problems with Stereo photogrammetry?
Problems due to tree cover / land cover and it is very time-consuming.
What are some pros and cons of LiDAR?
Pros: Post-processing results in raster surface / Gives you millions of points of data / It can map bare earth even with vegetation.
Cons: Very Very expensive and time-consuming in post processing.
Pro’s and Con’s of Modern Photogrammetry?
Pros: Advances in computing power, software and drones / Less expensive than LiDar / accuracy ~5cm possible / Results in both DEM and ocular imagery, so good for visualization
Cons: Does not do will with vegetation (>60%)
What are some benefits of using InSAR to map DEMs (satellite)
Generate high quality DEM models and measurements of displacement (by comparing two images). Not affected by weather. effective for mapping large area’s
How do you get collected data points to become surfaces?
Input points, whether collected by survey, photographs, LiDAR, ect, must be processed to create terrain models. Some require extensive post-structuring such as LiDAR.
The points are interpolated to create a surface with raster models (DEM), and triangulated to create vector models (TIN).
Of Tin and DEM, which represents Gradual changes and which Abrupt?
Tin = Abrupt (creates a surface of triangles between collected data points and thus has the ability to represent sharp changes in values like cliffs)
DEM = Gradual (interpolated surface using all of the collected points, creates a gradual surface between values)