Created
October 26, 2012 17:20
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Preliminary Geo Drawing in d3
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| var iD = {}; | |
| iD.Draw = function() { | |
| var event = d3.dispatch(draw, 'draw'), | |
| x0, x1, | |
| y0, y1; | |
| var feature = { | |
| type: 'Feature', | |
| geometry: { | |
| type: 'LineString', | |
| coordinates: [] | |
| } | |
| }; | |
| function draw() { | |
| this | |
| .on('mousemove.draw', mousemove) | |
| .on('click.draw', mousedown); | |
| } | |
| // move an elastic band that shows where the next point | |
| // will be | |
| function mousemove(e) { | |
| var target = this; | |
| function mouse() { | |
| var touches = d3.event.changedTouches; | |
| return touches ? d3.touches(target, touches)[0] : d3.mouse(target); | |
| } | |
| var ll = projection.invert(mouse()); | |
| var elastic = { | |
| type: 'Feature', | |
| geometry: { | |
| type: 'LineString', | |
| coordinates: [] | |
| } | |
| }; | |
| if (!feature.geometry.coordinates.length) { | |
| feature.geometry.coordinates[0] = ll; | |
| event.draw(feature); | |
| feature.geometry.coordinates = []; | |
| } else { | |
| var l = feature.geometry.coordinates.length - 1; | |
| elastic.geometry.coordinates = [ | |
| feature.geometry.coordinates[l], | |
| ll]; | |
| event.draw(feature, elastic); | |
| } | |
| } | |
| // add a point | |
| function mousedown(e) { | |
| var target = this; | |
| function mouse() { | |
| var touches = d3.event.changedTouches; | |
| return touches ? d3.touches(target, touches)[0] : d3.mouse(target); | |
| } | |
| var ll = projection.invert(mouse()); | |
| feature.geometry.coordinates.push(ll); | |
| event.draw(feature); | |
| d3.event.stopPropagation(); | |
| } | |
| return d3.rebind(draw, event, "on"); | |
| }; |
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| <!DOCTYPE html> | |
| <style> | |
| path { | |
| fill: none; | |
| } | |
| path.boundary { | |
| stroke: #2CA25F; | |
| stroke-width: 4; | |
| pointer-events:none; | |
| } | |
| path.elastic { | |
| stroke: #CF50C5; | |
| stroke-width: 4; | |
| pointer-events:none; | |
| } | |
| #axes { | |
| stroke: #BDBDBD; | |
| stroke-width: 0.5; | |
| } | |
| </style> | |
| <body> | |
| <script src="http://d3js.org/d3.v2.js"></script> | |
| <script src="draw.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 500, | |
| projection = d3.geo.mercator().scale(1024).translate([512, 256]), | |
| path = d3.geo.path().projection(projection); | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height) | |
| .call(d3.behavior.zoom() | |
| .translate(projection.translate()) | |
| .scale(projection.scale()) | |
| .on("zoom", redraw)); | |
| var axes = svg.append("g").attr("id", "axes"), | |
| xAxis = axes.append("line").attr("y2", height), | |
| yAxis = axes.append("line").attr("x2", width); | |
| var tileg = svg.append('g').attr('id', 'tiles'); | |
| var overlay = svg.append('g').attr('id', 'overlay'); | |
| function tileUrl(d) { | |
| return 'http://a.tiles.mapbox.com/v3/tmcw.map-hehqnmda/' + d.join('/') + '.png'; | |
| } | |
| function redraw() { | |
| if (d3.event) { | |
| projection | |
| .translate(d3.event.translate) | |
| .scale(d3.event.scale); | |
| } | |
| var t = projection.translate(), | |
| s = projection.scale(), | |
| z = Math.max(Math.log(s) / Math.log(2) - 8, 0); | |
| rz = Math.floor(z), | |
| ts = 256 * Math.pow(2, z - rz); | |
| // This is the 0, 0 px of the projection | |
| var tile_origin = [s / 2 - t[0], s / 2 - t[1]]; | |
| var tiles = []; | |
| var cols = d3.range(Math.max(0, Math.floor((tile_origin[0] - width) / ts)), | |
| Math.max(0, Math.ceil((tile_origin[0] + width) / ts))); | |
| var rows = d3.range(Math.max(0, Math.floor((tile_origin[1] - height) / ts)), | |
| Math.max(0, Math.ceil((tile_origin[1] + height) / ts))); | |
| cols.forEach(function(x) { | |
| rows.forEach(function(y) { | |
| tiles.push([Math.floor(z), x, y]); | |
| }); | |
| }); | |
| var tiles = tileg.selectAll('image.tile') | |
| .data(tiles, function(d) { return d.join(',') }); | |
| tiles.exit() | |
| .transition() | |
| .duration(250) | |
| .style("opacity", 0.0) | |
| .remove(); | |
| tiles.enter().append('image') | |
| .attr('class', 'tile') | |
| .attr('xlink:href', tileUrl); | |
| tiles.attr({ width: ts, height: ts }) | |
| .attr('transform', function(d) { | |
| return 'translate(' + [(d[1] * ts) - tile_origin[0], (d[2] * ts) - tile_origin[1]] + ')'; | |
| }) | |
| xAxis.attr("x1", t[0]).attr("x2", t[0]); | |
| yAxis.attr("y1", t[1]).attr("y2", t[1]); | |
| overlay.selectAll('path.boundary') | |
| .attr("d", path); | |
| } | |
| redraw(); | |
| overlay.insert("path") | |
| .attr("class", "boundary"); | |
| overlay.insert("path") | |
| .attr("class", "elastic"); | |
| var d = iD.Draw(); | |
| tileg.call(d); | |
| d.on('draw', function(feature, elastic) { | |
| console.log(elastic); | |
| overlay.selectAll('path.elastic') | |
| .data([elastic]) | |
| .attr("d", path); | |
| overlay.selectAll('path.boundary') | |
| .data([feature]) | |
| .attr("d", path); | |
| }); | |
| </script> |
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