Mitchell: The ESRI Guide to GIS Analysis, ch. 1
GIS technology 30 years old
Good for making maps: but can do more than that: GIS Analysis
- maps (and GIS) don’t just show us what exists, the help us discover new things, help make decisions
- maps result from GIS analysis: have important impact (visual)
Why GIS might not be used:
- lack of data (changing rapidly, but still a problem)
- difficult software (but now easy interfaces; still complex though)
- lack of understanding about GIS analysis capabilities (the book)
- where are things in geographic space?
- mapping variations in amount: least and most
- mapping density
- finding what is inside
- finding what is nearby
- mapping change
What is GIS Analysis?
GIS Analysis as a process
- simple visual analysis to complex digital modeling
- akin to the research process
1. Frame the Question:
- where are endangered ecosystems in Delaware County?
- where are potential recreational trail corridors in Delaware County?
- how can viable OWU food waste be efficiently distributed to area food banks?
- where does the food sold on campus come from, and what are the consequences of our consumption of these foods?
- what are the bird habitats on campus and how can they be enhanced?
- how can Delaware Run be restored in a campus-community-private sector collaboration?
- how can urban heat islands in central Ohio be assessed? Using what tools?
- how can drones be used with other remotely sensed imagery to assess environments?
- who is your audience? what is your final goal?
2. Understand your Data
- what is the context of your question? who are the experts? literature, people
- what do you have to know about the context of the question to answer it?
- best to do solid research first then start to ask/bother people: they are apt to be more helpful if you come to them knowing something
- what is an endangered ecosystem? what are specific examples?
- what are the goals of recreational trails? what do they connect?
- how is food waste reuse assessed and how is it collected?
- what or who can help you to understand the issue: literature, people
3. Choose a Method
- what data is available to help answer your question? source? cost? compatibility?
- what data do you have to generate yourself? easy vs. difficult vs impossible
- what specific data will you need for your project?
4. Process the Data: specific analysis
- ex) generate endangered areas by comparing areas defined as important ecosystems to their closeness to recent development
- ex) generate potential trails by generating important points and areas to connect; and determining feasible paths between those points; relate potential trails to property ownership and other factors
- ex) generate a plan for distributing food waste from campus to area food banks
- ex) analyze the global impact of specific food consumption on campus
- what kind of GIS or other analysis will you need to understand for your project?
5. Look at the Results
- generate a map (with a database) and use it to present results
- ex) map of endangered ecosystems in Delaware Co: distribute to ??
- ex) map of potential trails in Delaware Co.: planners, bike clubs, etc.
- ex) a map that guides distribution of OWU food waste
- ex) map of the global impact of what we eat
- vital part of the process: communication and advocacy
- Simple in concept; complex in application!
Understanding Geographic Features
- we reduce the complexity of the real world in order to collect data and map it
A feature: “something inherent and distinctive”
Types of features (mappable data)
1. Discrete Features: at any location, the feature is there or is not there
- point, line, and area example: p. 12
- corresponds to vector data structure in most GIS programs
2. Continuous Features: feature is everywhere in varying amounts
- ex) temperature
- ex) elevation
- ex) soil or bedrock (Delaware Data)
3) Features Summarized by Area: census or count data
- define an area; count features in the area; assign total to the area
- know how many features in an area, but not where they are in the area
ex) US Census data, animal census
Remember what I said about repetition of some concepts from reading to reading… as a way to assess concepts that are more important…
Two Ways of Representing Geographic Features
1) Vector: points, lines, and areas
- each point has a unique location in a coordinate system: latitude/longitude
- points connect to make lines
- series of points, connected to make lines, which close are areas
2) Raster: grid of varying resolution with cells
- air photo, remotely sensed image, camera image (drone, thermal data)
Different data structures; can be related in GIS but generated differently and stored and processed differently.
Review from Geog 222 or 353
- coordinate systems: based on the idea of a graph
- locations in geographic space: x, y
- latitude longitude vs state plane coordinate system
- coordinate layers of GIS information
- map projection
- 3D earth to 2D map
- distortions inherent in process (shape, area)
- distortions less evident at detailed scales
- but GIS layers must have same map projection or will not align properly
Understanding Geographic Attributes
- a geographic feature (point, line, area) has one or more attributes
- ex) area is a vernal pool, it is 1 acre, it is on private property (3 attributes)
Types of attribute values
- categories: qualitative
- ex) vernal pool (area) vs river (line)
Ranks: quantitative with order
- ex) water quality: high, medium, low
Counts and amounts: quantitative, total numbers
- ex) 35 robins in one nature reserve, 67 in a second reserve
Ratios: relationship between two quantities
- ex) people per household in census tracts in Delaware county
Data tables: the ‘database’ or spreadsheet where the feature attributes are found
- ex) select all properties in Delaware County that are residential land use
- ex) calculate and summarize the total value of all properties a proposed trail crosses
Course Project Ideas
- apply Mitchell’s process of GIS Analysis to project
- good example of proposal format and content: Wetlands / Delaware State Park PDF
Below the fold find additional material from previous course projects.
Focus: Green Trail / Campus Habitats (plants, animals, humans) / Environmental Monitoring
Michelle Lee (Stap student) searched using the keywords “environmental monitoring outdoor” and found some key concepts:
- human health – the importance of current research (Gak Map one two three report)
- pollution –
- ecology –
- measurable quantities –
- wireless equipment or remote sensing –
- network of sensors – important for a study of patterns and variation, thus important for significance of findings
- real-time monitoring – large data set implies difficulty analyzing the results (also flexibility interpreting the data), but its advantage lies in relevance to our daily lives (people can easily identify with it), in its applicability, as well as in its robustness (realistic setting reduces data misinterpretation)
- indoor (microenvironment) VS outdoor (microclimate – immediately around a building, where people congregate such that features of the place has a high human impact)
- biotic (involving animals, plants and human participants or research subjects) VS abiotic (chemical measurements)
- monetary investment
- statistical analysis and significance – choices choices choices, and implications
Some useful websites include
- A report on measuring tobacco smoke in Stanford U, compiled by website Exposure Science: this site hosts discussion and crowd-sourced materials on methodologies, tools, and findings for educational and research use.
- Wikipedia article on Environmental Monitoring
- EPA page on Environmental Monitoring
- Second International Conference in Sustainability in Energy and Buildings (SEB’10) includes a section on the importance of environmental monitoring on measuring success/progress in sustainability projects.
Student comments on project ideas
- agricultural issues
- light sensors (inside and outside)
- sustainable planning
- Green Business assessment
- Logistics / Business
- Trail Development
- Wind Turbine
- Kids & environment, “environmental deficit disorder”
- Kids & health and environment
- Health issues
- Food supply
- University Nature Preserves
- Easy access to data on what OWU has done with regards to sustainability
- interactive map linked to data
- future: modeling
- real-time electric use in Science Center: soon (and in other buildings)
- natural gas usage
- water / sewer usage
- academic vs residential split in garbage removal
- recycling: all goes to same place
- food waste / compost
- inventory of motion / occupancy sensors