fixed scale_denomitator
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4 changed files with 9 additions and 25 deletions
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@ -76,7 +76,7 @@ namespace mapnik
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try
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try
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{
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{
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projection proj(m_.srs()); // map projection
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projection proj(m_.srs()); // map projection
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double scale_denom = scale_denominator(m_,proj);
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double scale_denom = scale_denominator(m_,proj.is_geographic());
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std::clog << "scale denominator = " << scale_denom << "\n";
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std::clog << "scale denominator = " << scale_denom << "\n";
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std::vector<Layer>::const_iterator itr = m_.layers().begin();
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std::vector<Layer>::const_iterator itr = m_.layers().begin();
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@ -26,6 +26,5 @@
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namespace mapnik {
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namespace mapnik {
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class Map;
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class Map;
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class projection;
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MAPNIK_DECL double scale_denominator(Map const& map, bool geographic);
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MAPNIK_DECL double scale_denominator(Map const& map,projection const& prj);
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}
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}
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@ -173,7 +173,7 @@ namespace mapnik
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bool Layer::isVisible(double scale) const
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bool Layer::isVisible(double scale) const
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{
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{
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return isActive() && scale >= minZoom_ && scale < maxZoom_;
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return isActive() && scale >= minZoom_ - 1e-6 && scale < maxZoom_ + 1e-6;
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}
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}
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void Layer::setSelectable(bool selectable)
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void Layer::setSelectable(bool selectable)
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@ -23,32 +23,17 @@
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//$Id$
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//$Id$
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#include <cmath>
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#include <cmath>
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#include <mapnik/map.hpp>
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#include <mapnik/map.hpp>
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#include <mapnik/projection.hpp>
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#include <mapnik/distance.hpp>
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#include <mapnik/scale_denominator.hpp>
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#include <mapnik/scale_denominator.hpp>
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namespace mapnik {
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namespace mapnik {
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static const double dpi = 90.0; // display resolution
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static const double pi = 3.14159265359;
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static const double meters_per_degree = 6378137 * 2 * pi/ 360;
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double scale_denominator(Map const& map,projection const& prj)
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double scale_denominator(Map const& map, bool geographic)
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{
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{
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double map_width = map.getWidth();
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double denom = map.scale() / 0.00028;
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double map_height = map.getHeight();
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if (geographic) denom *= meters_per_degree;
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Envelope<double> const& extent = map.getCurrentExtent();
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return denom;
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double x0 = extent.minx();
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double y0 = extent.miny();
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double x1 = extent.maxx();
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double y1 = extent.maxy();
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if (!prj.is_geographic())
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{
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prj.inverse(x0,y0);
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prj.inverse(x1,y1);
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}
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great_circle_distance distance;
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double d1 = distance(coord2d(x0,y0),coord2d(x1, y1));
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double d0 = sqrt(map_width * map_width + map_height * map_height) / dpi * 0.0254;
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return d1 / d0;
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}
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}
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}
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}
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