Shaw Week
Chapter 1
- GIS is an acronym for Geographic information systems
- GIS has grown immensely since the creation of it, spatial scientists realized its potential and now helps analyze most world issues
- While spatial analysis has made great strides in advancement and accessibility learning the basics is still required to get a grasp on how to use tools
- GIS analysis is a way of looking at data and geographical patterns and finding relationships between them.
- Starting each analysis by doing something as simple as forming a question and finding an area where you want to explore.
- Types of features in GIS
- Discrete Features: locations and lines, the actual location can be pinpointed
- Continuous phenomena: entire area between boundaries, no differences in soil, land,vegetation.
- Geographic features can be represented in GIS using two models of the world vector and raster
- Vector: Each feature is a row in table, and feature shapes defined by x, and y locations in space.
- Raster : features are represented as a matrix of cells in continuous space, each layer represents one attribute.
- Map projections and coordinate systems are all the data layers being used should be the same in map projection and coordinate systems.
Chapter 2
- Mapping is used to see what, or where an individual feature is.
- This can help show an individual where they need to take action/ what areas meet your criteria you are looking for
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- This map allows wildlife officers to track the behavior of bears and assign officers to spots of need.
- There are many features for different layers.
- Each feature on the map needs a location in geographic coordinates
- The GIS stores the coordinates that are saved and draws the features.
- Using a subset of features allows you or the user to narrow down the the category value to something more specific or even make the range more broad
- Mapping features by category can provide understanding on how a place functions
- When showing categories on a map you want to only go up to 7 because most people can distinguish up to 7 categories on a map.
- In smaller areas that are being mapped, individual features are easier to distinguish, so more categories will also be easier to distinguish
Chapter 3
- People map where the most and least are to find places that meet their criteria and take action, or to see the relationships between places.
- To map the most and least you map features based on a quantity associated with each
- Adds an additional level of info beyond mapping the locations of features
- To map the most and least you assign symbols to features based on an attribute that contains a quantity.
- Ratios show you the relationships between two quantities, and are created by dividing one quantity by another, for each feature.
- Proportions show you what part of a whole each quantity represents.
- To calculate a proportion, you divide quantities that use the same measure.
- Densities show you where features are concentrated.
- To calculate density, you divide a value by the area
- Ranks put features in order, from high to low.
- Ranks are useful when direct measures are difficult or if the quantity represents a combination of factors