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gdal_featureset.cpp
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gdal_featureset.cpp
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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2017 Artem Pavlenko
*
* 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/datasource.hpp>
#include <boost/optional/optional_io.hpp>
#include <mapnik/image_scaling.hpp>
#include <mapnik/global.hpp>
#include <mapnik/debug.hpp>
#include <mapnik/image.hpp>
#include <mapnik/raster.hpp>
#include <mapnik/view_transform.hpp>
#include <mapnik/feature.hpp>
#include <mapnik/feature_factory.hpp>
// stl
#include <cmath>
#include <memory>
#include <sstream>
#include "gdal_featureset.hpp"
#include <gdal_priv.h>
using mapnik::box2d;
using mapnik::feature_ptr;
using mapnik::view_transform;
using mapnik::datasource_exception;
using mapnik::feature_factory;
#ifdef MAPNIK_LOG
namespace {
void get_overview_meta(GDALRasterBand* band)
{
int band_overviews = band->GetOverviewCount();
if (band_overviews > 0)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: " << band_overviews << " overviews found!";
for (int b = 0; b < band_overviews; b++)
{
GDALRasterBand * overview = band->GetOverview(b);
MAPNIK_LOG_DEBUG(gdal) << "Overview= " << b
<< " Width=" << overview->GetXSize()
<< " Height=" << overview->GetYSize();
}
}
else
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: No overviews found!";
}
int bsx,bsy;
double scale;
band->GetBlockSize(&bsx, &bsy);
scale = band->GetScale();
MAPNIK_LOG_DEBUG(gdal) << "Block=" << bsx << "x" << bsy
<< " Scale=" << scale
<< " Type=" << GDALGetDataTypeName(band->GetRasterDataType())
<< "Color=" << GDALGetColorInterpretationName(band->GetColorInterpretation());
}
} // anonymous ns
#endif
gdal_featureset::gdal_featureset(GDALDataset& dataset,
int band,
gdal_query q,
mapnik::box2d<double> extent,
unsigned width,
unsigned height,
int nbands,
double dx,
double dy,
boost::optional<double> const& nodata,
double nodata_tolerance)
: dataset_(dataset),
ctx_(std::make_shared<mapnik::context_type>()),
band_(band),
gquery_(q),
raster_extent_(extent),
raster_width_(width),
raster_height_(height),
dx_(dx),
dy_(dy),
nbands_(nbands),
nodata_value_(nodata),
nodata_tolerance_(nodata_tolerance),
first_(true)
{
ctx_->push("nodata");
}
gdal_featureset::~gdal_featureset()
{
}
GDALRIOResampleAlg gdal_featureset::get_gdal_resample_alg(mapnik::scaling_method_e mapnik_scaling_method)
{
switch (mapnik_scaling_method)
{
case mapnik::SCALING_NEAR: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Nearest Neighbor resampling"; return GRIORA_NearestNeighbour;
case mapnik::SCALING_BILINEAR: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Bilinear resampling"; return GRIORA_Bilinear;
case mapnik::SCALING_BICUBIC: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Cubic resampling"; return GRIORA_Cubic;
case mapnik::SCALING_SPLINE16: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL CubicSpline resampling"; return GRIORA_CubicSpline;
case mapnik::SCALING_SPLINE36: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL CubicSpline resampling"; return GRIORA_CubicSpline;
case mapnik::SCALING_HANNING: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Gauss resampling"; return GRIORA_Gauss;
case mapnik::SCALING_HAMMING: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Gauss resampling"; return GRIORA_Gauss;
case mapnik::SCALING_HERMITE: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Cubic resampling"; return GRIORA_Cubic;
case mapnik::SCALING_KAISER: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Lanczos resampling"; return GRIORA_Lanczos;
case mapnik::SCALING_QUADRIC: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Lanczos resampling"; return GRIORA_Lanczos;
case mapnik::SCALING_CATROM: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Cubic resampling"; return GRIORA_Cubic;
case mapnik::SCALING_GAUSSIAN: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Gauss resampling"; return GRIORA_Gauss;
case mapnik::SCALING_BESSEL: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Lanczos resampling"; return GRIORA_Lanczos;
case mapnik::SCALING_MITCHELL: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Cubic resampling"; return GRIORA_Cubic;
case mapnik::SCALING_SINC: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Lanczos resampling"; return GRIORA_Lanczos;
case mapnik::SCALING_LANCZOS: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Lanczos resampling"; return GRIORA_Lanczos;
case mapnik::SCALING_BLACKMAN: MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Using GDAL Lanczos resampling"; return GRIORA_Lanczos;
}
MAPNIK_LOG_WARN(gdal) << "No valid resampling method found using Nearest Neighbor";
return GRIORA_NearestNeighbour;
}
feature_ptr gdal_featureset::next()
{
if (first_)
{
first_ = false;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Next feature in Dataset=" << &dataset_;
return mapnik::util::apply_visitor(query_dispatch(*this), gquery_);
}
return feature_ptr();
}
feature_ptr gdal_featureset::get_feature(mapnik::query const& q)
{
feature_ptr feature = feature_factory::create(ctx_,1);
int raster_has_nodata = 0;
double raster_nodata = 0;
GDALRasterBand * red = 0;
GDALRasterBand * green = 0;
GDALRasterBand * blue = 0;
GDALRasterBand * alpha = 0;
GDALRasterBand * grey = 0;
CPLErr raster_io_error = CE_None;
/*
#ifdef MAPNIK_LOG
double tr[6];
dataset_.GetGeoTransform(tr);
const double dx = tr[1];
const double dy = tr[5];
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: dx_=" << dx_ << " dx=" << dx << " dy_=" << dy_ << "dy=" << dy;
#endif
*/
view_transform t(raster_width_, raster_height_, raster_extent_, 0, 0);
box2d<double> intersect = raster_extent_.intersect(q.get_bbox());
box2d<double> box = t.forward(intersect);
double filter_factor = q.get_filter_factor();
//size of resized output pixel in source image domain
double margin_x = 1.0 / (std::fabs(dx_) * std::get<0>(q.resolution()));
double margin_y = 1.0 / (std::fabs(dy_) * std::get<1>(q.resolution()));
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: margin_x=" << margin_x;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: margin_y=" << margin_y;
if (margin_x < 1)
{
margin_x = 1.0;
}
if (margin_y < 1)
{
margin_y = 1.0;
}
//select minimum raster containing whole box
int x_off = static_cast<int>(std::floor((box.minx() - margin_x) + .5));
int y_off = static_cast<int>(std::floor((box.miny() - margin_y) + .5));
int end_x = static_cast<int>(std::floor((box.maxx() + margin_x) + .5));
int end_y = static_cast<int>(std::floor((box.maxy() + margin_y) + .5));
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: x_off=" << x_off;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: y_off=" << y_off;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: end_x=" << end_x;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: end_y=" << end_y;
//clip to available data
if (x_off < 0)
{
x_off = 0;
}
if (y_off < 0)
{
y_off = 0;
}
if (end_x > (int)raster_width_)
{
end_x = raster_width_;
}
if (end_y > (int)raster_height_)
{
end_y = raster_height_;
}
// width and height of the portion of the source image we are requesting
int width = end_x - x_off;
int height = end_y - y_off;
double im_offset_x = x_off;
double im_offset_y = y_off;
// resolution is 1 / requested pixel size
const double width_res = std::get<0>(q.resolution());
const double height_res = std::get<1>(q.resolution());
int im_width = int(width_res * intersect.width() + 0.5);
int im_height = int(height_res * intersect.height() + 0.5);
// no upsampling in gdal
if (im_width > width)
{im_width=width;}
if (im_height > height)
{im_height=height;}
//calculate actual box2d of returned raster
box2d<double> feature_raster_extent(x_off, y_off, x_off + width, y_off + height);
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Feature Raster extent=" << feature_raster_extent;
feature_raster_extent = t.backward(feature_raster_extent);
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Raster extent=" << raster_extent_;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Feature Raster extent=" << feature_raster_extent;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: View extent=" << intersect;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Query resolution=" << std::get<0>(q.resolution()) << "," << std::get<1>(q.resolution());
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: StartX=" << x_off << " StartY=" << y_off << " Width=" << width << " Height=" << height;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: IM StartX=" << im_offset_x << " StartY=" << im_offset_y << " Width=" << im_width << " Height=" << im_height;
if (width > 0 && height > 0)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Requested Size from gdal=(" << width << "," << height << ")";
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Internal Image Size=(" << im_width << "," << im_height << ")";
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Reading band=" << band_;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: requested resampling method=" << scaling_method_to_string(q.get_scaling_method());
GDALRasterIOExtraArg psExtraArg;
INIT_RASTERIO_EXTRA_ARG(psExtraArg);
psExtraArg.eResampleAlg = get_gdal_resample_alg(q.get_scaling_method());
if (band_ > 0) // we are querying a single band
{
GDALRasterBand * band = dataset_.GetRasterBand(band_);
if (band_ > nbands_)
{
std::ostringstream s;
s << "GDAL Plugin: " << band_ << " is an invalid band, dataset only has " << nbands_ << "bands";
throw datasource_exception(s.str());
}
GDALDataType band_type = band->GetRasterDataType();
switch (band_type)
{
case GDT_Byte:
{
mapnik::image_gray8 image(im_width, im_height);
image.set(std::numeric_limits<std::uint8_t>::max());
raster_nodata = band->GetNoDataValue(&raster_has_nodata);
raster_io_error = band->RasterIO(GF_Read, x_off, y_off, width, height,
image.data(), image.width(), image.height(),
GDT_Byte, 0, 0, &psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
mapnik::raster_ptr raster = std::make_shared<mapnik::raster>(feature_raster_extent, intersect, image, filter_factor);
// set nodata value to be used in raster colorizer
if (nodata_value_) raster->set_nodata(*nodata_value_);
else raster->set_nodata(raster_nodata);
feature->set_raster(raster);
break;
}
case GDT_Float64:
case GDT_Float32:
{
mapnik::image_gray32f image(im_width, im_height);
image.set(std::numeric_limits<float>::max());
raster_nodata = band->GetNoDataValue(&raster_has_nodata);
raster_io_error = band->RasterIO(GF_Read, x_off, y_off, width, height,
image.data(), image.width(), image.height(),
GDT_Float32, 0, 0, &psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
mapnik::raster_ptr raster = std::make_shared<mapnik::raster>(feature_raster_extent, intersect, image, filter_factor);
// set nodata value to be used in raster colorizer
if (nodata_value_) raster->set_nodata(*nodata_value_);
else raster->set_nodata(raster_nodata);
feature->set_raster(raster);
break;
}
case GDT_UInt16:
{
mapnik::image_gray16 image(im_width, im_height);
image.set(std::numeric_limits<std::uint16_t>::max());
raster_nodata = band->GetNoDataValue(&raster_has_nodata);
raster_io_error = band->RasterIO(GF_Read, x_off, y_off, width, height,
image.data(), image.width(), image.height(),
GDT_UInt16, 0, 0, &psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
mapnik::raster_ptr raster = std::make_shared<mapnik::raster>(feature_raster_extent, intersect, image, filter_factor);
// set nodata value to be used in raster colorizer
if (nodata_value_) raster->set_nodata(*nodata_value_);
else raster->set_nodata(raster_nodata);
feature->set_raster(raster);
break;
}
case GDT_Int32:
{
mapnik::image_gray32s image(im_width, im_height);
image.set(std::numeric_limits<std::int32_t>::max());
raster_nodata = band->GetNoDataValue(&raster_has_nodata);
raster_io_error = band->RasterIO(GF_Read, x_off, y_off, width, height,
image.data(), image.width(), image.height(),
GDT_Int32, 0, 0, &psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
mapnik::raster_ptr raster = std::make_shared<mapnik::raster>(feature_raster_extent, intersect, image, filter_factor);
// set nodata value to be used in raster colorizer
if (nodata_value_) raster->set_nodata(*nodata_value_);
else raster->set_nodata(raster_nodata);
feature->set_raster(raster);
break;
}
default:
case GDT_Int16:
{
mapnik::image_gray16s image(im_width, im_height);
image.set(std::numeric_limits<std::int16_t>::max());
raster_nodata = band->GetNoDataValue(&raster_has_nodata);
raster_io_error = band->RasterIO(GF_Read, x_off, y_off, width, height,
image.data(), image.width(), image.height(),
GDT_Int16, 0, 0, &psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
mapnik::raster_ptr raster = std::make_shared<mapnik::raster>(feature_raster_extent, intersect, image, filter_factor);
// set nodata value to be used in raster colorizer
if (nodata_value_) raster->set_nodata(*nodata_value_);
else raster->set_nodata(raster_nodata);
feature->set_raster(raster);
break;
}
}
}
else // working with all bands
{
mapnik::image_rgba8 image(im_width, im_height);
image.set(std::numeric_limits<std::uint32_t>::max());
for (int i = 0; i < nbands_; ++i)
{
GDALRasterBand * band = dataset_.GetRasterBand(i + 1);
#ifdef MAPNIK_LOG
get_overview_meta(band);
#endif
GDALColorInterp color_interp = band->GetColorInterpretation();
switch (color_interp)
{
case GCI_RedBand:
red = band;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found red band";
break;
case GCI_GreenBand:
green = band;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found green band";
break;
case GCI_BlueBand:
blue = band;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found blue band";
break;
case GCI_AlphaBand:
alpha = band;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found alpha band";
break;
case GCI_GrayIndex:
grey = band;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found gray band";
break;
case GCI_PaletteIndex:
{
grey = band;
#ifdef MAPNIK_LOG
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found gray band, and colortable...";
GDALColorTable *color_table = band->GetColorTable();
if (color_table)
{
int count = color_table->GetColorEntryCount();
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Color Table count=" << count;
for (int j = 0; j < count; j++)
{
const GDALColorEntry *ce = color_table->GetColorEntry (j);
if (! ce) continue;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Color entry RGB=" << ce->c1 << "," <<ce->c2 << "," << ce->c3;
}
}
#endif
break;
}
case GCI_Undefined:
#if GDAL_VERSION_NUM <= 1730
if (nbands_ == 4)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found undefined band (assumming alpha band)";
alpha = band;
}
else
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found undefined band (assumming gray band)";
grey = band;
}
#else
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Found undefined band (assumming gray band)";
grey = band;
#endif
break;
default:
MAPNIK_LOG_WARN(gdal) << "gdal_featureset: Band type unknown!";
break;
}
}
if (red && green && blue)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Processing rgb bands...";
raster_nodata = red->GetNoDataValue(&raster_has_nodata);
GDALColorTable *color_table = red->GetColorTable();
bool has_nodata = nodata_value_ || raster_has_nodata;
// we can deduce the alpha channel from nodata in the Byte case
// by reusing the reading of R,G,B bands directly
if (has_nodata && !color_table && red->GetRasterDataType() == GDT_Byte)
{
double apply_nodata = nodata_value_ ? *nodata_value_ : raster_nodata;
// read the data in and create an alpha channel from the nodata values
// TODO - we assume here the nodata value for the red band applies to all bands
// more details about this at http://trac.osgeo.org/gdal/ticket/2734
float* imageData = (float*)image.bytes();
raster_io_error = red->RasterIO(GF_Read, x_off, y_off, width, height,
imageData, image.width(), image.height(),
GDT_Float32, 0, 0, &psExtraArg);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
int len = image.width() * image.height();
for (int i = 0; i < len; ++i)
{
if (std::fabs(apply_nodata - imageData[i]) < nodata_tolerance_)
{
*reinterpret_cast<unsigned *>(&imageData[i]) = 0;
}
else
{
*reinterpret_cast<unsigned *>(&imageData[i]) = 0xFFFFFFFF;
}
}
}
// Use dataset RasterIO in priority in 99.9% of the cases
if( red->GetBand() == 1 && green->GetBand() == 2 && blue->GetBand() == 3 )
{
int nBandsToRead = 3;
if( alpha != nullptr && alpha->GetBand() == 4 && !raster_has_nodata )
{
nBandsToRead = 4;
alpha = nullptr; // to avoid reading it again afterwards
}
raster_io_error = dataset_.RasterIO(GF_Read, x_off, y_off, width, height,
image.bytes(),
image.width(), image.height(), GDT_Byte,
nBandsToRead, nullptr,
4, 4 * image.width(), 1, &psExtraArg);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
}
else
{
raster_io_error = red->RasterIO(GF_Read, x_off, y_off, width, height, image.bytes() + 0,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
raster_io_error = green->RasterIO(GF_Read, x_off, y_off, width, height, image.bytes() + 1,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
raster_io_error = blue->RasterIO(GF_Read, x_off, y_off, width, height, image.bytes() + 2,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
}
// In the case we skipped initializing the alpha channel
if (has_nodata && !color_table && red->GetRasterDataType() == GDT_Byte)
{
double apply_nodata = nodata_value_ ? *nodata_value_ : raster_nodata;
if( apply_nodata >= 0 && apply_nodata <= 255 )
{
int len = image.width() * image.height();
GByte* pabyBytes = (GByte*) image.bytes();
for (int i = 0; i < len; ++i)
{
// TODO - we assume here the nodata value for the red band applies to all bands
// more details about this at http://trac.osgeo.org/gdal/ticket/2734
if (std::fabs(apply_nodata - pabyBytes[4*i]) < nodata_tolerance_)
pabyBytes[4*i + 3] = 0;
else
pabyBytes[4*i + 3] = 255;
}
}
}
}
else if (grey)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Processing gray band...";
raster_nodata = grey->GetNoDataValue(&raster_has_nodata);
GDALColorTable* color_table = grey->GetColorTable();
bool has_nodata = nodata_value_ || raster_has_nodata;
if (!color_table && has_nodata)
{
double apply_nodata = nodata_value_ ? *nodata_value_ : raster_nodata;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: applying nodata value for layer=" << apply_nodata;
// first read the data in and create an alpha channel from the nodata values
float* imageData = (float*)image.bytes();
raster_io_error = grey->RasterIO(GF_Read, x_off, y_off, width, height,
imageData, image.width(), image.height(),
GDT_Float32, 0, 0, &psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
int len = image.width() * image.height();
for (int i = 0; i < len; ++i)
{
if (std::fabs(apply_nodata - imageData[i]) < nodata_tolerance_)
{
*reinterpret_cast<unsigned *>(&imageData[i]) = 0;
}
else
{
*reinterpret_cast<unsigned *>(&imageData[i]) = 0xFFFFFFFF;
}
}
}
raster_io_error = grey->RasterIO(GF_Read, x_off, y_off, width, height, image.bytes() + 0,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
raster_io_error = grey->RasterIO(GF_Read,x_off, y_off, width, height, image.bytes() + 1,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
raster_io_error = grey->RasterIO(GF_Read,x_off, y_off, width, height, image.bytes() + 2,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure)
{
throw datasource_exception(CPLGetLastErrorMsg());
}
if (color_table)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: Loading color table...";
for (unsigned y = 0; y < image.height(); ++y)
{
unsigned int* row = image.get_row(y);
for (unsigned x = 0; x < image.width(); ++x)
{
unsigned value = row[x] & 0xff;
const GDALColorEntry *ce = color_table->GetColorEntry(value);
if (ce)
{
row[x] = (ce->c4 << 24)| (ce->c3 << 16) | (ce->c2 << 8) | (ce->c1) ;
}
else
{
// make lacking color entry fully alpha
// note - gdal_translate makes black
row[x] = 0;
}
}
}
}
}
if (alpha)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: processing alpha band...";
if (!raster_has_nodata || (red && green && blue))
{
raster_io_error = alpha->RasterIO(GF_Read, x_off, y_off, width, height, image.bytes() + 3,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
}
else
{
MAPNIK_LOG_WARN(gdal) << "warning: nodata value (" << raster_nodata << ") used to set transparency instead of alpha band";
}
}
else if( dataset_.GetRasterCount() > 0 && dataset_.GetRasterBand(1) )
{
// Check if we have a non-alpha mask band (for example a TIFF internal mask)
int flags = dataset_.GetRasterBand(1)->GetMaskFlags();
GDALRasterBand* mask = 0;
if (flags == GMF_PER_DATASET)
{
mask = dataset_.GetRasterBand(1)->GetMaskBand();
}
if (mask)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: found and processing mask band...";
if (!raster_has_nodata)
{
raster_io_error = mask->RasterIO(GF_Read, x_off, y_off, width, height, image.bytes() + 3,
image.width(), image.height(), GDT_Byte, 4, 4 * image.width(),
&psExtraArg);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
}
else
{
MAPNIK_LOG_WARN(gdal) << "warning: nodata value (" << raster_nodata << ") used to set transparency instead of mask band";
}
}
}
mapnik::raster_ptr raster = std::make_shared<mapnik::raster>(feature_raster_extent, intersect, image, filter_factor);
// set nodata value to be used in raster colorizer
if (nodata_value_)
{
raster->set_nodata(*nodata_value_);
}
else if (raster_has_nodata && !std::isnan(raster_nodata))
{
raster->set_nodata(raster_nodata);
}
feature->set_raster(raster);
}
// report actual/original source nodata in feature attributes
if (raster_has_nodata && !std::isnan(raster_nodata))
{
feature->put("nodata", raster_nodata);
}
return feature;
}
return feature_ptr();
}
feature_ptr gdal_featureset::get_feature_at_point(mapnik::coord2d const& pt)
{
CPLErr raster_io_error = CE_None;
if (band_ > 0)
{
unsigned raster_xsize = dataset_.GetRasterXSize();
unsigned raster_ysize = dataset_.GetRasterYSize();
double gt[6];
dataset_.GetGeoTransform(gt);
double det = gt[1] * gt[5] - gt[2] * gt[4];
// subtract half a pixel width & height because gdal coord reference
// is the top-left corner of a pixel, not the center.
double X = pt.x - gt[0] - gt[1]/2;
double Y = pt.y - gt[3] - gt[5]/2;
double det1 = gt[1]*Y + gt[4]*X;
double det2 = gt[2]*Y + gt[5]*X;
unsigned x = static_cast<unsigned>(det2/det);
unsigned y = static_cast<unsigned>(det1/det);
if (x < raster_xsize && y < raster_ysize)
{
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: pt.x=" << pt.x << " pt.y=" << pt.y;
MAPNIK_LOG_DEBUG(gdal) << "gdal_featureset: x=" << x << " y=" << y;
GDALRasterBand* band = dataset_.GetRasterBand(band_);
int raster_has_nodata;
double nodata = band->GetNoDataValue(&raster_has_nodata);
double value;
raster_io_error = band->RasterIO(GF_Read, x, y, 1, 1, &value, 1, 1, GDT_Float64, 0, 0);
if (raster_io_error == CE_Failure) {
throw datasource_exception(CPLGetLastErrorMsg());
}
if (!raster_has_nodata || value != nodata)
{
// construct feature
feature_ptr feature = feature_factory::create(ctx_,1);
feature->set_geometry(mapnik::geometry::point<double>(pt.x,pt.y));
feature->put_new("value",value);
if (raster_has_nodata && !std::isnan(nodata))
{
feature->put_new("nodata", nodata);
}
return feature;
}
}
}
return feature_ptr();
}