MatPlotLibNet.Geo 1.24.0

MatPlotLibNet.Geo

MatPlotLibNet.Geo adds geographic projections and maps to MatPlotLibNet: coastlines, borders, filled land and ocean, countries coloured by a value, places, bubbles, hexagon bins, flows and cartograms.

Quick Start

using MatPlotLibNet;
using MatPlotLibNet.Geo;
using MatPlotLibNet.Geo.Projections;

Plt.Create()
    .AddSubPlot(1, 1, 1, ax => ax
        .WithProjection(GeoProjection.Robinson)
        .Coastlines()
        .Borders())
    .Save("world_map.svg");

A map axes has one projection. WithProjection records it and every layer reads it, so Land(color), Ocean(color), Borders() and Coastlines() need no projection of their own. A layer asked for before the axes has a projection is refused with "call WithProjection first", and a layer that is given a projection has to give the axes' own (the same kind with the same numbers) or it is refused with an ArgumentException naming both.

A map coloured by a value

Choropleth colours each country by a value through a colour map. The values are joined to the built-in countries by their three-letter code (ADM0_A3), or Choropleth("POP_EST") reads a numeric property of the features:

using MatPlotLibNet;
using MatPlotLibNet.Geo;
using MatPlotLibNet.Geo.Projections;
using MatPlotLibNet.Styling.ColorMaps;

var populationMillions = new Dictionary<string, double> { ["FRA"] = 68, ["DEU"] = 84, ["ESP"] = 48 };

Plt.Create()
    .AddSubPlot(1, 1, 1, ax => ax
        .WithProjection(GeoProjection.Robinson)
        .Choropleth(populationMillions, ColorMaps.Viridis)
        .WithColorBar())
    .Save("choropleth.svg");

A country with no value is drawn in the colour map's bad colour, and the colour bar reads the range of the values that can be drawn.

Data on a map

A place the projection cannot place, such as the far side of an orthographic globe, is left out.

A map in JSON

A figure that holds a map comes back from JSON whole: the series writes its projection (its kind and the numbers it was made with), its features (the id of the built-in set, or a GeoJSON FeatureCollection with the holes kept), and its values, colour map and normaliser. The package registers the reader when it loads; a process that reads such JSON before it has used any type of this package calls GeoPolygonSeries.RegisterReader() once. A 1.23.0 reader leaves the map out with the diagnostic for a series kind it does not know.

Projections

The package ships 13 projections; the cookbook page lists them all and shows every layer with a picture.

Data

The package embeds Natural Earth data at 110m resolution:

• Coastlines (~50KB)
• Country borders (~150KB)

The data comes from Natural Earth and is public domain.