Notes
A repository dedicated to highlighting concepts and techniques in cartographic abstraction and practice. As such, very much always a work in progress.
The Isopleth
The Cuillins and Blà Bheinn on the Isle of Skye, Scotland. Contours are an applied form of isopleth; a line connecting points of equal value, in this case, elevation. As a pure form of abstraction, the contour is very revealing of landscape form.
Relief Shading
The Isle of Skye, Scotland. Inspired by the pioneering work of Swiss cartographer, Eduard Imhoff, the ‘Swiss style’ can have a subtlety and beauty that is the antithesis of the grossly exaggerated and unrealistic relief maps that we see endlessly repeated on social media platforms.
Figure-Ground
Glasgow, Scotland. A common technique in architectural, urban design and town planning practice. A simple but revealing representation of built form. The focus is on pattern and density. The city centre is self-evident and the course of the River Clyde reveals itself through its absence.
Graph Theory
A fundamental tenet to much cartographic practice. It provides a mathematical framework to represent and analyze maps. Applying this network topology to a map enables the calculation of themes such as isolation, adjacency, connectivity and routing.
Space Syntax
A direct application of graph theory, Space Syntax is a methodology for analysing space in terms of its network of connections and spaces, applying that to accessibility and movement, land use and economy, and other human interactions with space.
Generalisation
A foundational principle in cartographic abstraction; to reduce and clarify the information on a map for a given scale and audience, built on processes such as selection, aggregation, classification, exaggeration, displacement, merging, smoothing and simplification.
Simplification
Another of the foundational principles in cartographic abstraction. It exists to reduce and clarify the geometric information on a map for a given scale and audience without sacrificing topological relationships or geographical cognition.
Points. Lines. Polygons.
Of the two broad models for displaying geospatial data—vector and raster—the former is always constructed of these three types of discrete geometric objects. A simple way of understanding a map and its data types.
Cognitive Map
We all have this, and unique to each of us. Maps and experience enable us to develop a spatial understanding of the world around us, constructed in our minds. It's rarely accurate, geographically, but good enough to enable us to get from A–B, or have a sense place.
Map Typologies
There are four core map types: topographical, topological, thematic and artistic. This venn diagram examples just some of the map types you might come across. The world of cartography is richer and more diverse than is represented simply by Google Maps!
Visual Hierarchy
A fundamental method of dealing with information density, allowing the map reader to filter and dig down through many layers of information.
Flat Earth
The world isn’t flat! There are in fact more than 80 different map projections that translate our 3D world into 2D space. Unfortunately, most of us are only familiar with the Mercator projection (white background), which has somewhat distorted our understanding of global geography. Great for marine navigation, but not for other themes.
Graphicacy
Analogous to literacy, numeracy and articulacy, and equally important, graphicacy is a characterisation of cartographic and other visuo-spatial abilities, extending across the whole field of graphical communications. In essence, an important but uncommon skillset.
Delaunay Triangulation and Voronoi Diagram
These two entangled geometries find themselves applied to numerous spatial modelling activities, including digital terrain models; a triangulated irregular network (TIN). The Voronoi diagram (tesselation) can be used in regional and proximity analysis, and other related techniques such as convex hull.
North is Upwards
Due to differences in coordinate systems applied to the Earth, there are in fact three distinct ‘North’ directions; magnetic, grid and geographic. Magnetic North moves over time. Grid North is mathematically defined by local coordinate system. Geographic North hits the intersection of the Earth’s axis of rotation.
Isovists
A methodology and technique aligned with Space Syntax. Great for analysing the perception and visibility of space, along with the associated movement affordance. Applied in the fields of architecture and wayfinding.