Maps - Centroids, Bounds, Abstractions / Eric Field

Eric Field

Building and Using Tools to See. UVA Architecture + Data Science. IT Director. Instructor.

Workspace

Public

Maps

Edited

Apr 5, 2022

Fork of Maps (Geographic)

map = d3.select(mapContainer)

import {getMapData, drawMapLayer} from "@emfielduva/dvlib_maps"

world = getMapData("world110m")

mapLayers = {

let mapLayers = [];

mapLayers["countries"] = drawMapLayer(map,"countries",world.features,world.idField);

return mapLayers;

}

<style>

#countries path {fill: #eeeeee; stroke: #ccc}

</style>

import {centroids, geoCentroids, bounds, geoBounds} with {projection} from "@emfielduva/dvlib_maps"

projection = d3.geoMercator()

countryCentroids = {

let countryCentroids = geoCentroids(world.features, "id");

countryCentroids.forEach(d => {

d.lon = d.coord[0];

d.lat = d.coord[1];

});

return countryCentroids;

}

mapLayers["countrylabels"] = map.append("g").attr("id","countrylabels")

.selectAll("text")

.data(countryCentroids)

.join("text")

.attr("x", d => projection([d.lon,d.lat])[0])

.attr("y", d => projection([d.lon,d.lat])[1])

.text(d => d.name)

mapLayers["countryDots"] = map.append("g").attr("id","countryDots")

.selectAll("circle")

.data(countryCentroids)

.join("circle")

.attr("cx", d => projection([d.lon,d.lat])[0])

.attr("cy", d => projection([d.lon,d.lat])[1])

.attr("r", d => Math.random()*10) // random right now, but you get the idea.

import {rFromArea} from "@emfielduva/dvlib"

<style>

#countrylabels text {font-size: 10px; font-family: Arial,Helvetica,sans-serif; dominant-baseline: central;}

#countryDots circle {fill: blue; stroke: #ccc; opacity: 0.75;}

</style>

</svg>

textMap = d3.select(textMapContainer)

textMap.select("#countrylabels").selectAll("text")

.data(countryCentroids)

.join("text")

.attr("x", d => projection([d.lon,d.lat])[0])

.attr("y", d => projection([d.lon,d.lat])[1])

.text(d => d.name)

<style>

#circleslayer circle {fill: blue; stroke: #ccc; opacity: 0.75;}

</style>

</svg>

circleMap = d3.select(circleMapContainer)

circleMap.select("#circleslayer").selectAll("circle")

.data(countryCentroids)

.join("circle")

.attr("cx", d => projection([d.lon,d.lat])[0])

.attr("cy", d => projection([d.lon,d.lat])[1])

.attr("r",5) // of course this could also be sized from data.

<style>

#bblayer rect {fill: blue; stroke: #ccc; opacity: 0.75;}

#bblabels text {font-size: 10px; font-family: Arial,Helvetica,sans-serif;}

</style>

</svg>

bbMap = d3.select(boundingBoxMapContainer)

// using the planar (post projection) path.bounds for this one instead of spherical lon/lat

countryBBoxes = {

let countryBBoxes = bounds(world.features, "id");

countryBBoxes.forEach(d => {

// returned arrays are [left,bottom] then [right,top]

d.width = d.coord[1][0] - d.coord[0][0];

d.height = d.coord[1][1] - d.coord[0][1];

});

return countryBBoxes;

}

bbMap.select("#bblayer").selectAll("rect")

.data(countryBBoxes)

.join("rect")

.attr("x", d => d.coord[0][0])

.attr("y", d => d.coord[1][1])

.attr("width", d => d.width)

.attr("height", d => d.height)

bbMap.select("#bblabels").selectAll("text")

.data(countryBBoxes)

.join("text")

.attr("x", d => d.coord[0][0] + 2)

.attr("y", d => d.coord[1][1] + 10)

.text(d => d.name)

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