Cartography
Cartography is the discipline aimed at making maps.
Cartography has scientific, technical, and artistic foundations.
Cartography
Scientific foundations
Mathematics is one of the pillars of cartography: geodetic systems, coordinate reference systems are fundamental tools for map making.
The preparation of maps (data management and transformations) is a process that requires precision and accuracy .
The cartographic process is based on a set of rules from the semiology of graphics and on strong methodological tools.
Cartography
Scientific foundations
The map itself is the subject of numerous researches: communication efficiency, animated cartography, optimization of flow mapping…
Cartography
Technical foundations
Cartography is based on the acquisition, preparation and processing of data. It requires the use of specialized software products (spreadsheets, GIS, mapping software, spatial databases…).
Cartography
Artistic foundations
The process of map creation usually involves a search for aesthetics, design, and a certain viewpoint on spatial phenomena.
As with any communication object, the graphic design of a map has an impact on the transmission of the message.
Cartography
Artistic foundations
What are the maps used for?
What are the maps used for?
Analysis (reveal phenomena and spatial organisation)
What are the maps used for?
What are the maps used for?
Visualizing its own territory, navigating
Take a step back
The context of production is important.
To better understand the issues of legibility and communication of the cartographic message, ask yourself
- What is my role in producing a map?
- What is the purpose of my map, how do I want people to respond to it?
- Who is the intended audience? What do they need to know to understand it?
This directly influences the *geographic bounding box** and *projection** used, the *generalization** of the map background, the *graphic choices** (fonts, colors, format), the *vocabulary** used.
What about the thematic map?
A widely appreciated tool for analysis, decision support and communication.
It is necessary to identify the graphical means that allow to go from a “simple” spatialized statistical information to an efficient graphical representation.
M A P S !
M for message
The message to be conveyed. The message should be coherent, clear, understandable and as simple as possible so that it can be easily integrated.
A for artistic
A map should be attractive. It should be aesthetically pleasing and well designed.
P for people
The map should be designed for a specific purpose. The mapmaker needs to know whom he/she is addressing.
S for scientific
The map is a professional tool of the geographer. It is a scientific object that follows strict and precise rules, it must be as reproducible as possible and thus open to scientific discussion/dispute.
The Cartographic Language
The Cartographic Language
1. Use the rules from the semiology of graphics
2. Use the cartographic codes and conventions
Semiology of graphics
Jacques Bertin has developed a set of rules for the graphical representation of information.
3 types of relationships
Differentiation: express relationships of equivalence or difference, with no hierarchy or classification.
Order: express a hierarchy in the data.
Proportionality: express raw quantities.
3 types of relationships
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Visual variables
A visual variable refers to the way in which graphical figures are made to vary in order to visually represent variations in statistical data.
- size
- value
- color
- shape
- orientation
- texture
Visual variables
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Localization and positioning
Localization refers to the position of a place on Earth’s surface. It is a geographical notion.
Positioning refers to the graphic transcription of geographical objects on a map using points, lines, or polygons. Is is a cartographic concept.
Absolute quantitative data
ONLY one visual variable can be used to show absolute quantitative data: the size.
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It is the only visulal variable that can express differences, hierarchy and above all proportionality.
Absolute quantitative data
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Absolute quantitative data
Absolute quantitative data
Absolute quantitative data
Absolute quantitative data
Absolute quantitative data
Relative quantitative data
(and qualitative ordinal data)
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Relative quantitative data
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Relative quantitative data
The choropleth map: A cartographic representation consisting of ordered coloured areas on a grid (e.g. administrative division).
Used with relative quantitative data and ordered qualitative data.
Before the choropleth map…
The statistical information in your spreadsheet is not always ready to be mapped.
The information may need to be converted, collated or reduced to make it understandable.
Relative quantitative data (rates, indices, etc.) always need to be synthesised, broken down into classes of values.
This process is often called discretization.
Discretization
- Summarize the statistical series
- Position parameters (mean, median, mode…)
- Dispersion parameters (standard deviation, interquartile interval…)
- Analyse the distribution
- Histogram, box plot, distribution chart
- …
- Determine class intervals
Discretization
- Classes must be homogeneous and distinct
- The number of classes must be smaller than the number of observations
- Essential characteristics of the distribution should be preserved (extent, dispersion, shape of the distribution)
- Use rounded limits, or use relevant values. Boundary values should be easy to read an remember
Discretization
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Discretization
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Relative quantitative data
Relative quantitative data
Relative quantitative data
Relative quantitative data
Relative quantitative data
Qualitative ordinal data
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Qualitative nominative data
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Qualitative nominative data
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Qualitative nominative data
Qualitative nominative data
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Qualitative nominative data
Qualitative nominative data
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Qualitative nominative data
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To sum up and simplify
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Codes & Conventions
Codes & Conventions help contextualize the map.
Mandatory elements:
- Title
- Date
- Legend
- Source (and author)
- Scalebar
- North arrow
Scale bar
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General layout of the map
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Cartographic composition
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