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/****************************************************************************
*
* (c) 2009-2016 QGROUNDCONTROL PROJECT <http://www.qgroundcontrol.org>
*
* QGroundControl is licensed according to the terms in the file
* COPYING.md in the root of the source code directory.
*
****************************************************************************/
#include "SHPFileHelper.h"
#include <QFile>
#include <QVariant>
#include <QtDebug>
const char* SHPFileHelper::_errorPrefix = QT_TR_NOOP("SHP file load failed. %1");
bool SHPFileHelper::_validateSHPFiles(const QString& shpFile, QString& errorString)
{
errorString.clear();
if (shpFile.endsWith(QStringLiteral(".shp"))) {
QString prjFilename = shpFile.left(shpFile.length() - 4) + QStringLiteral(".prj");
QFile prjFile(prjFilename);
if (prjFile.exists()) {
if (prjFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
QTextStream strm(&prjFile);
QString line = strm.readLine();
if (!line.startsWith(QStringLiteral("GEOGCS[\"GCS_WGS_1984\","))) {
errorString = QString(_errorPrefix).arg(tr("Only WGS84 projections are supported."));
}
} else {
errorString = QString(_errorPrefix).arg(tr("PRJ file open failed: %1").arg(prjFile.errorString()));
}
} else {
errorString = QString(_errorPrefix).arg(tr("File not found: %1").arg(prjFilename));
}
} else {
errorString = QString(_errorPrefix).arg(tr("File is not a .shp file: %1").arg(shpFile));
}
return errorString.isEmpty();
}
SHPHandle SHPFileHelper::_loadShape(const QString& shpFile, QString& errorString)
{
SHPHandle shpHandle = Q_NULLPTR;
errorString.clear();
if (_validateSHPFiles(shpFile, errorString)) {
if (!(shpHandle = SHPOpen(shpFile.toUtf8(), "rb"))) {
errorString = QString(_errorPrefix).arg(tr("SHPOpen failed."));
}
}
return shpHandle;
}
ShapeFileHelper::ShapeType SHPFileHelper::determineShapeType(const QString& shpFile, QString& errorString)
{
ShapeFileHelper::ShapeType shapeType = ShapeFileHelper::Error;
errorString.clear();
SHPHandle shpHandle = SHPFileHelper::_loadShape(shpFile, errorString);
if (errorString.isEmpty()) {
int cEntities, type;
SHPGetInfo(shpHandle, &cEntities /* pnEntities */, &type, Q_NULLPTR /* padfMinBound */, Q_NULLPTR /* padfMaxBound */);
qDebug() << "SHPGetInfo" << shpHandle << cEntities << type;
if (cEntities != 1) {
errorString = QString(_errorPrefix).arg(tr("More than one entity found."));
} else if (type == SHPT_POLYGON) {
shapeType = ShapeFileHelper::Polygon;
} else {
errorString = QString(_errorPrefix).arg(tr("No supported types found."));
}
}
SHPClose(shpHandle);
return shapeType;
}
bool SHPFileHelper::loadPolygonFromFile(const QString& shpFile, QList<QGeoCoordinate>& vertices, QString& errorString)
{
double vertexFilterMeters = 5;
SHPHandle shpHandle = Q_NULLPTR;
SHPObject* shpObject = Q_NULLPTR;
errorString.clear();
vertices.clear();
shpHandle = SHPFileHelper::_loadShape(shpFile, errorString);
if (!errorString.isEmpty()) {
goto Error;
}
int cEntities, shapeType;
SHPGetInfo(shpHandle, &cEntities, &shapeType, Q_NULLPTR /* padfMinBound */, Q_NULLPTR /* padfMaxBound */);
if (shapeType != SHPT_POLYGON) {
errorString = QString(_errorPrefix).arg(tr("File does not contain a polygon."));
goto Error;
}
shpObject = SHPReadObject(shpHandle, 0);
if (shpObject->nParts != 1) {
errorString = QString(_errorPrefix).arg(tr("Only single part polygons are supported."));
goto Error;
}
for (int i=0; i<shpObject->nVertices; i++) {
vertices.append(QGeoCoordinate(shpObject->padfY[i], shpObject->padfX[i]));
}
// Filter last vertex such that it differs from first
{
QGeoCoordinate firstVertex = vertices[0];
while (vertices.count() > 3 && vertices.last().distanceTo(firstVertex) < vertexFilterMeters) {
vertices.removeLast();
}
}
// Filter vertex distances to be larger than 1 meter apart
{
int i = 0;
while (i < vertices.count() - 2) {
if (vertices[i].distanceTo(vertices[i+1]) < vertexFilterMeters) {
vertices.removeAt(i+1);
} else {
i++;
}
}
}
Error:
if (shpObject) {
SHPDestroyObject(shpObject);
}
if (shpHandle) {
SHPClose(shpHandle);
}
return errorString.isEmpty();
}