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@jkutianski
Last active Dec 23, 2015
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Comparación entre proyección mercator y mercator transversa para la Argentina

A la proyección mercator es necesario ajustarle 2°por la deformación existente el la parte sur de la Argentina.

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<!DOCTYPE html>
<meta charset="utf-8">
<style>
.graticule {
fill: none;
stroke: black;
stroke-opacity: .5;
stroke-width: .5px;
}
.land {
fill: gray;
stroke: white;
stroke-width: .5px;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/d3.geo.projection.v0.min.js"></script>
<script src="http://d3js.org/topojson.v1.min.js"></script>
<script>
var width = 960/2,
height = 500;
var svg,
projection,
path,
graticule;
d3.json("argentina_indec.json", function(error, json) {
// Transverse Mercator
svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);
projection = d3.geo.transverseMercator()
.center([2.5, -38.5])
.rotate([66, 0])
.scale((height * 56.5) / 33)
.translate([(width / 2), (height / 2)]);
path = d3.geo.path()
.projection(projection);
graticule = d3.geo.graticule()
.extent([[-180,-90], [0,0]])
.step([3, 3]);
svg.append("path")
.datum(graticule)
.attr("class", "graticule")
.attr("d", path);
svg.selectAll("text")
.data(topojson.feature(json, json.objects.provincias).features)
.enter()
.append("path")
.attr("d", path)
.attr("class", "land");
svg.append("text")
.text("Transverse Mercator")
.attr("x", 10)
.attr("y", 25)
.attr("fill", "blue")
.attr("style","font-family: Arial, Helvetica, sans-serif; font-weight: bold; font-style: normal");
// Mercator
svg = d3.select("body")
.append("svg")
.attr("width", width)
.attr("height", height);
projection = d3.geo.mercator()
// debe ajustarse 2° (-40.5 en lugar de -38.5) ya que el centro geografico
// esta desfasado por la deformacion del territorio cercano a los polos.
.center([2.5, -40.5])
.rotate([66, 0])
// tambien debe ajustarse la escala ya que la proyeccion mercator es mas larga
.scale((height * 43) / 33)
.translate([(width / 2), (height / 2)]);
path = d3.geo.path()
.projection(projection);
graticule = d3.geo.graticule()
.extent([[-180,-90], [0,0]])
.step([3, 3]);
svg.append("path")
.datum(graticule)
.attr("class", "graticule")
.attr("d", path);
svg.selectAll("text")
.data(topojson.feature(json, json.objects.provincias).features)
.enter()
.append("path")
.attr("d", path)
.attr("class", "land");
svg.append("text")
.text("Mercator")
.attr("x", 10)
.attr("y", 25)
.attr("fill", "blue")
.attr("style","font-family: Arial, Helvetica, sans-serif; font-weight: bold; font-style: normal");
});
d3.select(self.frameElement).style("height", height + "px");
</script>
</body>
</html>
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