mapnik/src/metawriter.cpp

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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2010 Hermann Kraus
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
// Mapnik
#include <mapnik/metawriter.hpp>
#include <mapnik/metawriter_json.hpp>
// Boost
#include <boost/foreach.hpp>
#include <boost/algorithm/string.hpp>
// STL
#include <iomanip>
#include <cstdio>
namespace mapnik {
UnicodeString const& metawriter_property_map::operator[](std::string const& key) const
{
std::map<std::string, UnicodeString>::const_iterator it;
it = m_.find(key);
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if (it == m_.end()) return not_found_;
return (*it).second;
}
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metawriter_properties::metawriter_properties(boost::optional<std::string> str)
{
if (str) {
boost::split(*this, *str, boost::is_any_of(", "), boost::token_compress_on);
}
}
/********************************************************************************************/
void metawriter_json_stream::start(metawriter_property_map const& properties)
{
assert(f_);
*f_ << "{ \"type\": \"FeatureCollection\", \"features\": [\n";
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count = 0;
}
void metawriter_json_stream::stop()
{
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if (count >= 0 && f_) {
*f_ << " ] }\n";
}
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count = -1;
}
metawriter_json_stream::~metawriter_json_stream()
{
if (count >= 0) {
#ifdef MAPNIK_DEBUG
std::cerr << "WARNING: GeoJSON metawriter not stopped before destroying it.";
#endif
stop();
}
}
metawriter_json_stream::metawriter_json_stream(metawriter_properties dflt_properties)
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: metawriter(dflt_properties), count(-1), f_(0) {}
void metawriter_json_stream::add_box(box2d<double> box, Feature const &feature,
proj_transform const& prj_trans, CoordTransform const &t,
const metawriter_properties& properties)
{
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#ifdef MAPNIK_DEBUG
if (count < 0)
{
std::cerr << "WARNING: Metawriter not started before using it.\n";
}
#endif
/* Coordinate transform in renderer:
input: layer srs
prj_trans.backwards() [prj_trans: map -> layer]
intermediate: map srs
t_.forward()
output: pixels
Our transform:
input: pixels
t_.backward()
intermediate: map srs (available via prj_trans.source())
trans.forward()
output: WGS84
*/
proj_transform trans(prj_trans.source(), projection("+proj=latlong +datum=WGS84"));
//t_ coord transform has transform for box2d combined with prj_trans
box = t.backward(box, trans);
double minx = box.minx();
double miny = box.miny();
double maxx = box.maxx();
double maxy = box.maxy();
if (count++) *f_ << ",\n";
*f_ << std::fixed << std::setprecision(8) << "{ \"type\": \"Feature\",\n \"geometry\": { \"type\": \"Polygon\",\n \"coordinates\": [ [ [" <<
minx << ", " << miny << "], [" <<
maxx << ", " << miny << "], [" <<
maxx << ", " << maxy << "], [" <<
minx << ", " << maxy << "] ] ] }," <<
"\n \"properties\": {";
std::map<std::string, value> fprops = feature.props();
int i = 0;
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BOOST_FOREACH(std::string p, properties)
{
std::map<std::string, value>::const_iterator itr = fprops.find(p);
std::string text;
if (itr != fprops.end())
{
//Property found
text = boost::replace_all_copy(boost::replace_all_copy(itr->second.to_string(), "\\", "\\\\"), "\"", "\\\"");
}
if (i++) *f_ << ",";
*f_ << "\n \"" << p << "\":\"" << text << "\"";
}
*f_ << "\n} }";
}
/********************************************************************************************/
metawriter_json::metawriter_json(metawriter_properties dflt_properties, path_expression_ptr fn)
: metawriter_json_stream(dflt_properties), fn_(fn) {}
void metawriter_json::start(metawriter_property_map const& properties)
{
std::string filename =
path_processor<metawriter_property_map>::evaluate(*fn_, properties);
#ifdef MAPNIK_DEBUG
std::clog << "Metawriter JSON: filename=" << filename << "\n";
#endif
f_.open(filename.c_str(), std::fstream::out | std::fstream::trunc);
if (f_.fail()) perror((std::string("Metawriter JSON: Failed to open file ") + filename).c_str());
set_stream(&f_);
metawriter_json_stream::start(properties);
}
void metawriter_json::stop()
{
metawriter_json_stream::stop();
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if (f_.is_open()) {
f_.close();
}
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#ifdef MAPNIK_DEBUG
else {
std::clog << "WARNING: File not open in metawriter_json::stop()!\n";
}
#endif
}
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};