• spatial analysis is used to support decisions
    • provides insights to enables informed choices
    • GIS will not make the decisions itself however
    • GIS may be only used to explore various scenarios
      • by being able to alter parameters
    • preferable to making mistakes that impact families, health, world and planet
  • tools explored in past weeks
    • queries to filter datasets
    • proximity like tools to find relational data
    • next up: topology

topology

topological data: information about the relative position of spatial features
  • example of a topological map:
    • the map of a subway

topological properties

  • connectivity: to find routes between places
  • orientation: to find direction of river flow
  • adjacency: find which region is next to another
  • containment: how many islands within a kale

example

  • how many children can access new planned sports facility?
    • find nearby children using proximity
    • use buffer for chosen area or use adjacent areas using topology
      • the choice depends on the data available
    • what is an area? what is nearby? how far are thing away from each other

suitability analysis

  • weighs locations relative to each other based on given criteria using spatial and attribute queries and/or overlay methods
    • spatial and attribute analysis
    • overlay analysis to evaluate potential locations
  • applicable for finding best locations for
    • business sites
    • pipeline paths
    • flooding risks

site suitability model

  • to find locations that meets requirements, use
    • logical queries, then
    • spatial queries, then
    • analysis
  • the queries together form a model
    • example - logical query of a particular size
    • followed by a spatial queries to identify parcels within one mile of road
    • and outside the flood zone
boolean suitability: describes locations as either suitable or not suitable based on a true or false (logical) condition
cost path analysis: finds the best pathways between two locations that costs the least to traverse using the cost of time, distance, or some other criteria
  • optimal route needs to provide the least cost path
    • cost maybe specified in terms of distance, time, effort etc
    • cost is anything that deters travel
  • both suitability modeling and cost path analysis use similar methods to arrive at a decision
    • the criteria can be difficult to define technically
    • you are the expert
    • the choice of criteria and parameters for the analysis are subjective
  • the criteria are often based on either
    • first-hand experience or
    • expert knowledge (including published studies) or
    • industry standards

configurable apps