This example demonstrates how to create a custom Cartesian projection by implementing a geometry transform on top of two linear scales; the geometry transform is then used in lieu of a geographic projection, which are intended for displaying spherical geometry.
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October 27, 2016 18:07
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Custom Cartesian Projection
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| license: gpl-3.0 |
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| .lot { | |
| fill: lightgray; | |
| stroke: black; | |
| } | |
| </style> | |
| <svg width="960" height="500"></svg> | |
| <script src="https://d3js.org/d3.v4.min.js"></script> | |
| <script> | |
| var svg = d3.select("svg"), | |
| width = +svg.attr("width"), | |
| height = +svg.attr("height"); | |
| var x = d3.scaleLinear() | |
| .range([0, width]); | |
| var y = d3.scaleLinear() | |
| .range([0, height]); | |
| var projection = d3.geoTransform({ | |
| point: function(px, py) { | |
| this.stream.point(x(px), y(py)); | |
| } | |
| }); | |
| var path = d3.geoPath() | |
| .projection(projection); | |
| d3.json("geo.json", function(error, geo) { | |
| if (error) throw error; | |
| x.domain(d3.extent(geo.features, function(d) { return d.properties.Easting; })); | |
| y.domain(d3.extent(geo.features, function(d) { return d.properties.Northing; })); | |
| svg.append("path") | |
| .datum(geo) | |
| .attr("class", "lot") | |
| .attr("d", path); | |
| }); | |
| </script> |
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