Lecture #1 Flashcards
(26 cards)
Why is geographic space so complex?
We have lots of infinite geographic space, so we have to be selective
Some geography can’t be seen
What is the difference between GIScience and GISystems?
GISystems are tools. GIScience is the theory that informs
The following can be defined as what?
A tool used to project data on a map
GISystems
What are the steps from real world phenomena to visual representations?
(RSRD) Real world -> Spatial phenomena -> Representation -> Display of representation
What questions should we ask about spatial analysis?
Who, what, why, where & how?
What is the goal of GIS?
Maps are not the goal, but rather improved insight and understanding are
What defines a feature?
You need to outline a definition
How do we classify entities?
Point, line or polygon
What is the difference between continuous and discrete spatial phenomena?
Discrete phenomena is something that doesn’t exist everywhere, and is easily identifiable (houses, trees)
Continuous phenomena is something that exists everywhere (tree density)
What is continuous variation and how do we make these values discrete?
Continuous variation is things that exist everywhere but vary such as air pressure. We need to put these into groups by assigning catagories (discretization)
What are the methods of discretization?
Taking measurements at sample points, taking measures at transects and cross-sections, drawing contours and dividing the area into zones (SCZC)
What are the issues with discretization?
They are approximations and data could be missing
What is indeterminate boundaries?
Boundaries where you need to set them yourself such as when does a group of trees become a forest
What is the difference between analogue and digital data?
Analogue data is drawn out where digital is digital
What are the 4 components of GIS?
Data, hardware, software, users
What is a thematic map?
A map representing something
What is a general purpose map?
A reference map showing things like borders
How does GPS work?
A satellite emits a signal, provides a distance from satellite to you on ground depending on how long the signal took, works with multiple satellites to work out where you are
What is remote sensing?
Sensing and capturing an object without actually physically being there
What is LIDAR?
Light detection and ranging, it provides point clouds which can become 3d representations of phenomena
What is SFM?
Structure from motion is when you take multiple photographs of something and use 3d algorithms to determine what the rest of the structure will end up looking like
What is signal degradation?
The process of blocking signals using materials to weaken their signal
What is the difference between accuracy and precision in a GIS context?
Accuracy is the conceptual accuracy or geographic position accuracy while precision is the description and meta data of the data
What is an absolute frame of reference?
We don’t need an anchor, we use a system like coordiantes
