- Introduction to the course
- Basic theory behind GIS
- Motivation
- Practical Example
- Homework
- Discussion
This webpage is an auxiliary material to the lecture Spatial data in Humanities. This lecture is part of the course ARTS020 - Digital Humanities that took place at Masaryk University, Brno, in 2020. This course aims to explain the theoretical basics behind Geographic Information Systems, discuss some examples of their use in Humanities, and provide a short practical example.
- QGIS application installed
- STANDALONE STABLE version is recommended
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GIS
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An equivalent to "Geospatial"
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Geographical Information SCIENCE
- Scientific discipline
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Geographical Information SYSTEMS
- Software / General tools - ArcGIS, QGIS
- Built-in systems
- Frameworks / libraries for data manipulation, visualization...
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Cartography
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"Drawing" and understanding maps - a depiction of the geographical space
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More historical term
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Mathematical cartography (how to transform globe to the map), visualization (what is the best way to "draw" our data), theoretical cartography
Map of Margraviate of Moravia, made by Komensky in ~1624. Taken from Wikipedia.
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Geoinformatics
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An equivalent to "Geomatics"
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Heavy use of IT
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Scripting the methods
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Spatial data analysis (processing geospatial data), web-based maps (map web applications), Localization services (GPS)
Areas of Geoinformatics. Taken from zgis.at.
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Remote sensing
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Processing images from satellites or airplanes
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Application in ecology, agriculture, forest management...
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Detection of changes in forest health, estimation damages after a natural disaster
Illustration of Remote Sensing process. Taken from www.flaticon.com and Remote sensing from space.
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Two types of data
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Raster data
- Pixel-based / image like datasets
- Formats - png, tiff, jpg...
- Spatially continuous information - satellite images, elevation, land cover, temperature
- Space is divided into pixels, each pixel holds a value / set of values
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Vector data
- Defined by coordinates / mathematically
- Formats - shp, geojson, pdf, svg
- Topology - points, lines, polygons
- Spatially discrete information - points of interest, rivers / streets / borders, regions
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Layers
GIS layers.
- Manipulating (filtering, extending, combining) of spatial datasets to extract new information
- Detection of hotspots of crime in the city, predicting temperatures in a set of regions
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Attribute types
- Categorical / Qualitative - dominant crop in the region, name of the local mayor, type of transportation
- Numerical / Quantitative - average annual temperature, population number
- Boolean - areas with snow
- Ordinal - position in a ranking
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Graphical variables
- Size
- Shape
- Color hue / value / saturation
- Orientation
- Point symbols
- Simple - mostly just a symbol that communicates a single value through its size, color, or shape
- Glyphs - one symbol "communicates" more variables; a complex system of symbolization
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Line symbols
- Identifications - the feature is generalized by the line; railroads, trails, rivers
- Borders - the feature is enclosed by the line; regions, areas
- Movement - the line symbol (arrow) shows the angle that important for the understanding of the feature; wind movement, migration
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Polygons
- Regions - all features are on the same level of importance, we just need to define their position; a simple political map
- Choropleth - features are visualized to represent a quantitative variable
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Heatmap
- display the intensity of the phenomenon in space
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3D
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Transformation of the Earth's globe surface into a flat plane with the system of mathematical equations
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This way, we can define every position on the planet / in a region
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WGS (World Geodetic System) - a system of XY coordinates
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Cartographic projections playground
- Every phenomenon that relates to the geographical space
- There are many fields of human activity that are dependent on GIS.
- Meteorology
- Transportation
- Ecology
- Urban planning
- Agriculture ...
- Long tradition of sketching maps in all kind of sciences
- Constraints:
- Data quality (validity, uncertainty, incompleteness)
- Preferences in qualitative approaches
- Untrust to the process of generalization (?)
- Statistical / Mathematical / Programming skills required
- ...
- Create a new table in MS Excel, LibreOffice Calc, Google Spreadsheets...
- Rows are records; columns are variables
- Two columns for geographic coordinates - X and Y
- Define value domains for each column - e.g., column "label" is a text, column "certainty" is a boolean (TRUE, FALSE values), and column "price" is a number
- Fill the values for each record based on the defined domains
- Run QGIS and create a new Project
Open Data Source Manager
(Ctrl + L) and chooseDelimited Text
- Select the .csv file into the first input (
File Name
)
- list of available XYTiles:
- https://wiki.openstreetmap.org/wiki/Tile_servers
- https://qms.nextgis.com/#
- https://www.spatialbias.com/2018/02/qgis-3.0-xyz-tile-layers/
- https://leaflet-extras.github.io/leaflet-providers/preview/
- replace {s} with
subdomains
value
- replace {s} with
- https://geoportal.cuzk.cz/
- WMS / WMTS
Služby
->Prohlížení
- some base layers need an additional authentification (
apikey
), some are "down", some are very "slow" - recommended to start with OSM
https://tile.openstreetmap.org/{z}/{x}/{y}.png
- Right-click on the layer in the
Layers
panel ->Properties
->Symbolization
- There are several visualization methods to use
- most basic methods: Graduated (Quantitative data) and Categorized (Qualitative Data)
- Different possibilities for Vector and Raster data
- Right click on the layer in the
Layers
panel ->Properties
->Labels
- Choose
Single labels
and select the label attribute in theValue
form
New layout
(Ctrl + P) -> Enter name- Add map components to the layout - title, texts, images, scales, legend...
- Try to explain, "What information do you want to give to the readers." Ideally, try to show something that would be "hidden" without the map
- Create a map composition in QGIS to display your spatial (point-based) dataset
- Its recommended to use any graphical editor (yes, also MS Paint) to finish the composition
- Data should come from your study, research, your interest - anything that you have some insight into. This insight is crucial for interpreting the map.
- Before creating the map, think about the main idea (spatial pattern) you want to communicate. And based on this, choose the visualization method and other map components wisely
- After you create the map - show it to someone without any explanation to see whether he/she understands your "message". If not, think about a better way to communicate that "message."
- At the end - add a free-form text to the map composition where you describe the map, the dataset, and the reasoning behind that process (3-5 sentences...).
- link to the lecture notes https://adammertel.github.io/GIS-and-humanities/
- QGIS: A Gentle Introduction to GIS
- Manuel Gimond: Intro to GIS and Spatial Analysis
- UC Berkeley: GIS data types: Vector VS Raster
- David J. Buckey: GIS Introduction
- ICSM: Commonly used map projections
- GISGeography: Degrees/Minutes/Seconds (DMS) vs Decimal Degrees(DD)
- University Consortium for GIS: GIS and T Body of Knowledge
- Jim Vallandingham: vallandingham.me blog
- Stanford University: Center for Spatial and Textual Analysis
- University of Virginia Library: Spatial Humanities Scholars lab