Lecture 1,2 + Chapter 1,2 Flashcards
What kind of questions can we answer with maps?
- disease transmitted areas
- population density
- election results
- migration patterns
What is a map
a map is a representation of some area (real or imaginary) usually on a flat surface
What do maps do
- show a larger area than what we can see
- present information of interest
- demonstrate spatial relationships
What are the 2 major types of maps
- reference maps
- thematic maps
What is a reference map
reference maps show lots of data
- show a variety of features
- general store houses of info
EX: map of uoft, transportation routes, rivers etc
what is a thematic map
highlights specific themes
- overall goal is focus the users attention on specific features
- can tell by the title
- EX: low income areas, minority groups
T/F All maps are models
True
- they are representations of reality but they are not reality themselves
T/F All maps are political
True
- maps are socially constructed
- people decide what to include and what not to include depending how they want you to interpret the map
- pakistan/india, borders, etc
First known map of the world
The Babylonian Map
- diagrams that categorized features and symbolizes of the location of the creator
Brief of history of maps
- Babylonian map
- Ptolemy’s map
- T and O map
- Al-Idrisi - islamic
- Cantino map
- Mercator projection
- thematic maps
- analytical maps
- geographic info maps
What does GIS stand for
Geographic Information System
- computer systems used to store, display and analyze spatial information
Liberal Education
creative insights and knowledge are acquired and used
- how they change over time
- engages you through reading, symbolization, classifying data, visual/statistical data
Spatial Data
a fundamental component of understanding contemporary society
- it can describe the position, dimensions, and relationships between geographic features like cities, rivers, roads, or buildings
Why is mapping important?
- understanding wide range of data
- represents society and technology of its time
- GPS
- thematic maps - crime hotspots, identify routes, vulnerability, disease etc
What are the 3 characteristics of map data
- Spatial data (where an object is located)
- Temporal data (when the data is collected and accurate)
- Attribute data (what characteristics the object or event has - population, income, etc)
Metadata
Data about data that describes such as the source, content, methods, developers, accuracy
- datasets much have: attribute information, metadata reference information, lineage, data quality info
What are the 2 types of data collection
- Direct collection (ground)
- Remote sensing (satellite)
What is direct collection and how is it collected
- data collected through direct interaction with a particular place
- surveys, geocoding, sensors, GPS units, trilateration
What are surveys
- used as a way of direct collection
gathering attribute data about individuals, households, or locations - number of trees on a street
- census
What is a census
census data serves a vital role in helping understanding our society
- allocation of government resources
- large scale surveys (country, provinces, territories
- today census can be filled out online, answering a series of question (every 10 years)
- EX: election results
What are some problems associated with census data
- accuracy
- undercounting (marginalized populations, poor)
- plenty of topics that are not covered
- religion, consumer spending, political parties
what is geocoding
- used as a way of direct collection
the process of attaching a geographic location to some sort of address information - takes address –> into coordinates to be plotted on a map
- STEPS: converts the input into address, multiple interpretation, presents the user with the best matches of the location
What are sensors
- used as a way of direct collection
- tools or devices that collect info about the environment around them
What does GPS stand for
Global Positioning Systems
What is a GPS
system that uses satellites to collect location data
- space segment (satellites that send signals to earth)
-control segment (maintenance of satellites about data control)
-user segment (receivers on the ground that process satellite info)
How does GPS work
based on velocity = distance/time
- transmits signals to the earths surface and shows their position in space at that certain point
- a direct line of sight is required for signal
What is trilateration and how it is calculated
- used as a way of direct collection
used to pinpoint the position of a person or location by knowing the distances from 3 different locations - drawing circles - finding circumference - only one location that fits all the circles
What is remote sensing
- 2nd type of data collection
- collecting data from afar, taking pictures from a plane/satellite
- sensors that detect nonvisible parts of the electromagnetic spectrum
- monitors changes in the environment over large areas
- deforestation, oil spills etc
What is a landsat
the longest running satellite imagery program
- land/water, coloured infrared - vegetation etc
3 problems of spatial data
- Resolution (the specificity of data)
- Accuracy (how well the data aligns with the real world)
- Interoperability (how well the 2 datasets align with each other)
3 types of resolution
- Spatial Resolution (the smallest unit of area measured in the dataset
- Attribute Resolution (the level of distinction between categories)
- Temporal Resolution (the frequency at which the data was collected)
Spatial Resolution Explained
quality of a computer screen
larger pictures with smaller pixels have better resolution
larger pictures with large pixels = bad quality
if you have a map that shows a large area you want a lower resolution (larger pixels)
Attribution resolution explained
the degree to which distinctions are made
- like if a map show ages of individuals across a country there should be more than one range in the data to better accommodate all ages and represent them all more clearly
**the more categories = higher resolution
Temporal resolution explained
how often is the measurement taken
- it would not make sense to describe how a neighborhood has changed in the last 5 years with data that is taken every 10 years
What are the 3 types of accuracy data issues
- Spatial Accuracy
- Attribute Accuracy
- Temporal Accuracy
What is spatial accuracy
how well the location of an object is reflected on the map
- if boundaries are drawn wrong or signals are blocked by trees
What is attribute accuracy
whether characteristics reported about an object are true
- if participants do not respond, misunderstand or purposely provide false info (might be for census)
What is temporal accuracy
Whether details about an object are up-to-date with respect to changes in the world
- objects in printed maps might be less accurate bc more urbanization and updates are happening in the world.
what is interoperability and what are the 3 types
it describes how well 2 different datasets work with each other - are they comparing the same areas or categories
1. Spatial interoperability
2. Attribute interoperability
3. Temporal interoperability
what is spatial interoperability
how well do spatial units match up
It ensures that geographic data from various sources or platforms can be shared, combined, and used effectively without losing meaning or accuracy, regardless of differences in formats, standards, or software environments.
what is attribute interoperability
how well 2 datasets match
individuals in the past could only pick racial categories from 3 areas, now there’s more variety - about 15
the past had poor attribute interoperability because they have a very low attribute resolution (more categories = higher resolution)
what is temporal interoperability
how well do the reported times match up
- makes sure if info collected or generated at different times, or from different time zones and temporal resolutions, can be used together accurately without issues
- EX: time zone consistency
