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Backport for measuring from trunk to 0.8. Not everything is ported, b… 
…ut the main functionality should at least be correct.

git-svn-id: http://svn.osgeo.org/qgis/branches/Release-0_8_0@6818 c8812cc2-4d05-0410-92ff-de0c093fc19c
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homann committed Mar 18, 2007
1 parent 185a7fc commit 1f23ba9d5e8a89d9d489a07a48031c1d5db4233a
Showing with 292 additions and 95 deletions.
  1. +223 −56 src/core/qgsdistancearea.cpp
  2. +19 −5 src/core/qgsdistancearea.h
  3. +50 −34 src/gui/qgsmeasure.cpp
279 src/core/qgsdistancearea.cpp
View file
@@ -17,27 +17,34 @@
#include <cmath>
#include <sqlite3.h>
#include <QDir>
#include <QSettings>
#include <QString>
#include <QLocale>
#include <QObject>

#include "qgis.h"
#include "qgspoint.h"
#include "qgsproject.h"
#include "qgscoordinatetransform.h"
#include "qgsspatialrefsys.h"
#include "qgsgeometry.h"
#include "qgsdistancearea.h"
#include "qgsapplication.h"
#include "qgslogger.h"

// MSVC compiler doesn't have defined M_PI in math.h
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

#define DEG2RAD(x) ((x)*M_PI/180)


QgsDistanceArea::QgsDistanceArea()
{
// init with default settings
mProjectionsEnabled = FALSE;
mCoordTransform = new QgsCoordinateTransform;
setDefaultEllipsoid();
setProjectAsSourceSRS();
setSourceSRS(GEOSRS_ID); // WGS 84
setEllipsoid("WGS84");
}


@@ -47,27 +54,17 @@ QgsDistanceArea::~QgsDistanceArea()
}


void QgsDistanceArea::setSourceSRS(long srsid)
void QgsDistanceArea::setProjectionsEnabled(bool flag)
{
QgsSpatialRefSys srcSRS;
srcSRS.createFromSrsId(srsid);
mCoordTransform->setSourceSRS(srcSRS);
mProjectionsEnabled = flag;
}


void QgsDistanceArea::setProjectAsSourceSRS()
void QgsDistanceArea::setSourceSRS(long srsid)
{
// This function used to only get the /ProjectSRSID if on-the-fly
// projection was enabled (and used a default value in all other
// cases). However, even if it was not, a valid value for
// /ProjectSRSID is most likely available, and we now use it in all
// cases (as it gives correct distances and areas even when
// on-the-fly projection is turned off). The default of GEOSRS_ID
// is still applied if all else fails.

int srsid = QgsProject::instance()->readNumEntry("SpatialRefSys","/ProjectSRSID",GEOSRS_ID);

setSourceSRS(srsid);
QgsSpatialRefSys srcSRS;
srcSRS.createFromSrsId(srsid);
mCoordTransform->setSourceSRS(srcSRS);
}


@@ -81,6 +78,14 @@ bool QgsDistanceArea::setEllipsoid(const QString& ellipsoid)
const char *myTail;
sqlite3_stmt *myPreparedStatement;
int myResult;

// Shortcut if ellipsoid is none.
if (ellipsoid == "NONE")
{
mEllipsoid = "NONE";
return true;
}

//check the db is available
myResult = sqlite3_open(QString(QgsApplication::qgisUserDbFilePath()).latin1(), &myDatabase);
if(myResult)
@@ -170,26 +175,6 @@ bool QgsDistanceArea::setEllipsoid(const QString& ellipsoid)
}


bool QgsDistanceArea::setDefaultEllipsoid()
{
QString defEll("WGS84");
QString ellKey("/qgis/measure/ellipsoid");
QSettings settings;
QString ellipsoid = settings.readEntry(ellKey, defEll);

// Somehow/sometimes the settings file can have a blank ellipsoid
// value. This is undesirable, so force a valid default value in
// that case, and fix the problem by writing a valid value.
if (ellipsoid.isEmpty())
{
ellipsoid = defEll;
settings.writeEntry(ellKey, ellipsoid);
}

return setEllipsoid(ellipsoid);
}


double QgsDistanceArea::measure(QgsGeometry* geometry)
{
unsigned char* wkb = geometry->wkbBuffer();
@@ -246,6 +231,7 @@ unsigned char* QgsDistanceArea::measureLine(unsigned char* feature, double* area

std::vector<QgsPoint> points(nPoints);

QgsDebugMsg("This feature WKB has " + QString::number(nPoints) + " points");
// Extract the points from the WKB format into the vector
for (unsigned int i = 0; i < nPoints; ++i)
{
@@ -265,18 +251,32 @@ double QgsDistanceArea::measureLine(const std::vector<QgsPoint>& points)
if (points.size() < 2)
return 0;

double total = 0;
QgsPoint p1, p2;

try
{
double total = 0;
QgsPoint p1, p2;
p1 = mCoordTransform->transform(points[0]);

for (int i = 1; i < points.size(); i++)
if (mProjectionsEnabled && (mEllipsoid != "NONE"))
p1 = mCoordTransform->transform(points[0]);
else
p1 = points[0];

for (std::vector<QgsPoint>::size_type i = 1; i < points.size(); i++)
{
p2 = mCoordTransform->transform(points[i]);
total = computeDistanceBearing(p1,p2);
if (mProjectionsEnabled && (mEllipsoid != "NONE"))
{
p2 = mCoordTransform->transform(points[i]);
total += computeDistanceBearing(p1,p2);
}
else
{
p2 = points[i];
total += measureLine(p1,p2);
}

p1 = p2;
}

return total;
}
catch (QgsCsException &cse)
@@ -291,9 +291,17 @@ double QgsDistanceArea::measureLine(const QgsPoint& p1, const QgsPoint& p2)
{
try
{
QgsPoint pp1 = mCoordTransform->transform(p1);
QgsPoint pp2 = mCoordTransform->transform(p2);
return computeDistanceBearing(pp1, pp2);
QgsPoint pp1 = p1, pp2 = p2;
if (mProjectionsEnabled && (mEllipsoid != "NONE"))
{
pp1 = mCoordTransform->transform(p1);
pp2 = mCoordTransform->transform(p2);
return computeDistanceBearing(pp1, pp2);
}
else
{
return sqrt((p2.x()-p1.x())*(p2.x()-p1.x()) + (p2.y()-p1.y())*(p2.y()-p1.y()));
}
}
catch (QgsCsException &cse)
{
@@ -328,14 +336,18 @@ unsigned char* QgsDistanceArea::measurePolygon(unsigned char* feature, double* a

// Extract the points from the WKB and store in a pair of
// vectors.
for (unsigned int jdx = 0; jdx < nPoints; jdx++)
for (int jdx = 0; jdx < nPoints; jdx++)
{
x = *((double *) ptr);
ptr += sizeof(double);
y = *((double *) ptr);
ptr += sizeof(double);

points[jdx] = mCoordTransform->transform(QgsPoint(x,y));
points[jdx] = QgsPoint(x,y);
if (mProjectionsEnabled && (mEllipsoid != "NONE"))
{
points[jdx] = mCoordTransform->transform(points[jdx]);
}
}

if (points.size() > 2)
@@ -359,14 +371,22 @@ unsigned char* QgsDistanceArea::measurePolygon(unsigned char* feature, double* a

double QgsDistanceArea::measurePolygon(const std::vector<QgsPoint>& points)
{

try
{
std::vector<QgsPoint> pts(points.size());
for (std::vector<QgsPoint>::size_type i = 0; i < points.size(); i++)
if (mProjectionsEnabled && (mEllipsoid != "NONE"))
{
pts[i] = mCoordTransform->transform(points[i]);
std::vector<QgsPoint> pts(points.size());
for (std::vector<QgsPoint>::size_type i = 0; i < points.size(); i++)
{
pts[i] = mCoordTransform->transform(points[i]);
}
return computePolygonArea(pts);
}
else
{
return computePolygonArea(points);
}
return computePolygonArea(pts);
}
catch (QgsCsException &cse)
{
@@ -376,6 +396,20 @@ double QgsDistanceArea::measurePolygon(const std::vector<QgsPoint>& points)
}


double QgsDistanceArea::getBearing(const QgsPoint& p1, const QgsPoint& p2)
{
QgsPoint pp1 = p1, pp2 = p2;
if (mProjectionsEnabled && (mEllipsoid != "NONE"))
{
pp1 = mCoordTransform->transform(p1);
pp2 = mCoordTransform->transform(p2);
}

double bearing;
computeDistanceBearing(pp1, pp2, &bearing);
return bearing;
}


///////////////////////////////////////////////////////////
// distance calculation
@@ -512,6 +546,11 @@ double QgsDistanceArea::computePolygonArea(const std::vector<QgsPoint>& points)
double Qbar1, Qbar2;
double area;

QgsDebugMsg("Ellipsoid: " + mEllipsoid);
if ((! mProjectionsEnabled) || (mEllipsoid == "NONE"))
{
return computePolygonFlatArea(points);
}
int n = points.size();
x2 = DEG2RAD(points[n-1].x());
y2 = DEG2RAD(points[n-1].y());
@@ -556,3 +595,131 @@ double QgsDistanceArea::computePolygonArea(const std::vector<QgsPoint>& points)
return area;
}

double QgsDistanceArea::computePolygonFlatArea(const std::vector<QgsPoint>& points)
{
// Normal plane area calculations.
double area = 0.0;
int i, size;

size = points.size();

// QgsDebugMsg("New area calc, nr of points: " + QString::number(size));
for(i = 0; i < size; i++)
{
// QgsDebugMsg("Area from point: " + (points[i]).stringRep(2));
// Using '% size', so that we always end with the starting point
// and thus close the polygon.
area = area + points[i].x()*points[(i+1) % size].y() - points[(i+1) % size].x()*points[i].y();
}
// QgsDebugMsg("Area from point: " + (points[i % size]).stringRep(2));
area = area / 2.0;
return fabs(area); // All areas are positive!
}

QString QgsDistanceArea::textUnit(double value, int decimals, QGis::units u, bool isArea)
{
QString unitLabel;


switch (u)
{
case QGis::METERS:
if (isArea)
{
if (fabs(value) > 1000000.0)
{
unitLabel = QObject::tr(" km2");
value = value / 1000000.0;
}
else if (fabs(value) > 1000.0)
{
unitLabel = QObject::tr(" ha");
value = value / 10000.0;
}
else
{
unitLabel = QObject::tr(" m2");
}
}
else
{
if (fabs(value) == 0.0)
{
// Special case for pretty printing.
unitLabel=QObject::tr(" m");

}
else if (fabs(value) > 1000.0)
{
unitLabel=QObject::tr(" km");
value = value/1000;
}
else if (fabs(value) < 0.01)
{
unitLabel=QObject::tr(" mm");
value = value*1000;
}
else if (fabs(value) < 0.1)
{
unitLabel=QObject::tr(" cm");
value = value*100;
}
else
{
unitLabel=QObject::tr(" m");
}
}
break;
case QGis::FEET:
if (isArea)
{
if (fabs(value) > (528.0*528.0))
{
unitLabel = QObject::tr(" sq mile");
value = value / (5280.0*5280.0);
}
else
{
unitLabel = QObject::tr(" sq ft");
}
}
else
{
if (fabs(value) > 528.0)
{
unitLabel = QObject::tr(" mile");
value = value / 5280.0;
}
else
{
if (fabs(value) == 1.0)
unitLabel=QObject::tr(" foot");
else
unitLabel=QObject::tr(" feet");
}
}
break;
case QGis::DEGREES:
if (isArea)
{
unitLabel = QObject::tr(" sq.deg.");
}
else
{
if (fabs(value) == 1.0)
unitLabel=QObject::tr(" degree");
else
unitLabel=QObject::tr(" degrees");
}
break;
case QGis::UNKNOWN:
unitLabel=QObject::tr(" unknown");
default:
std::cout << "Error: not picked up map units - actual value = "
<< u << std::endl;
};


return QLocale::system().toString(value, 'f', decimals) + unitLabel;

}

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