//! Sets ellipsoid by supplied radii
// Inverse flattening is calculated with invf = a/(a-b)
// Also, b = a-(a/invf)
bool QgsDistanceArea::setEllipsoid( double semiMajor, double semiMinor )
{
mEllipsoid = QString( "PARAMETER:%1:%2" ).arg( semiMajor ).arg( semiMinor );
mSemiMajor = semiMajor;
mSemiMinor = semiMinor;
mInvFlattening = mSemiMajor / ( mSemiMajor - mSemiMinor );
computeAreaInit();
return true;
}
//! Copy helper. Avoid Sqlite3 accesses.
void QgsDistanceArea::_copy( const QgsDistanceArea & origDA )
{
mEllipsoidalMode = origDA.mEllipsoidalMode;
mEllipsoid = origDA.mEllipsoid;
mSemiMajor = origDA.mSemiMajor;
mSemiMinor = origDA.mSemiMinor;
mInvFlattening = origDA.mInvFlattening;
// Some calculations and trig. Should not be TOO time consuming.
// Alternatively we could copy the temp vars?
computeAreaInit();
mCoordTransform = origDA.mCoordTransform;
}
//! Copy helper. Avoid Sqlite3 accesses.
void QgsDistanceArea::_copy( const QgsDistanceArea & origDA )
{
mEllipsoidalMode = origDA.mEllipsoidalMode;
mEllipsoid = origDA.mEllipsoid;
mSemiMajor = origDA.mSemiMajor;
mSemiMinor = origDA.mSemiMinor;
mInvFlattening = origDA.mInvFlattening;
// Some calculations and trig. Should not be TOO time consuming.
// Alternatively we could copy the temp vars?
computeAreaInit();
delete mCoordTransform;
mCoordTransform = new QgsCoordinateTransform( origDA.mCoordTransform->sourceCrs(), origDA.mCoordTransform->destCRS() );
}
bool QgsDistanceArea::setEllipsoid( const QString& ellipsoid )
{
QString radius, parameter2;
//
// SQLITE3 stuff - get parameters for selected ellipsoid
//
sqlite3 *myDatabase;
const char *myTail;
sqlite3_stmt *myPreparedStatement;
int myResult;
// Shortcut if ellipsoid is none.
if ( ellipsoid == GEO_NONE )
{
mEllipsoid = GEO_NONE;
return true;
}
// Check if we have a custom projection, and set from text string.
// Format is "PARAMETER:<semi-major axis>:<semi minor axis>
// Numbers must be with (optional) decimal point and no other separators (C locale)
// Distances in meters. Flattening is calculated.
if ( ellipsoid.startsWith( "PARAMETER" ) )
{
QStringList paramList = ellipsoid.split( ':' );
bool semiMajorOk, semiMinorOk;
double semiMajor = paramList[1].toDouble( & semiMajorOk );
double semiMinor = paramList[2].toDouble( & semiMinorOk );
if ( semiMajorOk && semiMinorOk )
{
return setEllipsoid( semiMajor, semiMinor );
}
else
{
return false;
}
}
// Continue with PROJ.4 list of ellipsoids.
//check the db is available
myResult = sqlite3_open_v2( QgsApplication::srsDbFilePath().toUtf8().data(), &myDatabase, SQLITE_OPEN_READONLY, nullptr );
if ( myResult )
{
QgsMessageLog::logMessage( QObject::tr( "Can't open database: %1" ).arg( sqlite3_errmsg( myDatabase ) ) );
// XXX This will likely never happen since on open, sqlite creates the
// database if it does not exist.
return false;
}
// Set up the query to retrieve the projection information needed to populate the ELLIPSOID list
QString mySql = "select radius, parameter2 from tbl_ellipsoid where acronym='" + ellipsoid + '\'';
myResult = sqlite3_prepare( myDatabase, mySql.toUtf8(), mySql.toUtf8().length(), &myPreparedStatement, &myTail );
// XXX Need to free memory from the error msg if one is set
if ( myResult == SQLITE_OK )
{
if ( sqlite3_step( myPreparedStatement ) == SQLITE_ROW )
{
radius = QString( reinterpret_cast< const char * >( sqlite3_column_text( myPreparedStatement, 0 ) ) );
parameter2 = QString( reinterpret_cast< const char * >( sqlite3_column_text( myPreparedStatement, 1 ) ) );
}
}
// close the sqlite3 statement
sqlite3_finalize( myPreparedStatement );
sqlite3_close( myDatabase );
// row for this ellipsoid wasn't found?
if ( radius.isEmpty() || parameter2.isEmpty() )
{
QgsDebugMsg( QString( "setEllipsoid: no row in tbl_ellipsoid for acronym '%1'" ).arg( ellipsoid ) );
return false;
}
// get major semiaxis
if ( radius.left( 2 ) == "a=" )
mSemiMajor = radius.mid( 2 ).toDouble();
else
{
QgsDebugMsg( QString( "setEllipsoid: wrong format of radius field: '%1'" ).arg( radius ) );
return false;
}
// get second parameter
// one of values 'b' or 'f' is in field parameter2
// second one must be computed using formula: invf = a/(a-b)
if ( parameter2.left( 2 ) == "b=" )
{
mSemiMinor = parameter2.mid( 2 ).toDouble();
mInvFlattening = mSemiMajor / ( mSemiMajor - mSemiMinor );
}
else if ( parameter2.left( 3 ) == "rf=" )
{
mInvFlattening = parameter2.mid( 3 ).toDouble();
mSemiMinor = mSemiMajor - ( mSemiMajor / mInvFlattening );
}
else
{
QgsDebugMsg( QString( "setEllipsoid: wrong format of parameter2 field: '%1'" ).arg( parameter2 ) );
return false;
}
QgsDebugMsg( QString( "setEllipsoid: a=%1, b=%2, 1/f=%3" ).arg( mSemiMajor ).arg( mSemiMinor ).arg( mInvFlattening ) );
// get spatial ref system for ellipsoid
QString proj4 = "+proj=longlat +ellps=" + ellipsoid + " +no_defs";
QgsCoordinateReferenceSystem destCRS;
destCRS.createFromProj4( proj4 );
//TODO: createFromProj4 used to save to the user database any new CRS
// this behavior was changed in order to separate creation and saving.
// Not sure if it necessary to save it here, should be checked by someone
// familiar with the code (should also give a more descriptive name to the generated CRS)
if ( destCRS.srsid() == 0 )
{
QString myName = QString( " * %1 (%2)" )
.arg( QObject::tr( "Generated CRS", "A CRS automatically generated from layer info get this prefix for description" ),
destCRS.toProj4() );
destCRS.saveAsUserCRS( myName );
}
//
// set transformation from project CRS to ellipsoid coordinates
mCoordTransform->setDestCRS( destCRS );
mEllipsoid = ellipsoid;
// precalculate some values for area calculations
computeAreaInit();
return true;
}
bool QgsDistanceArea::setEllipsoid( const QString& ellipsoid )
{
QString radius, parameter2;
//
// SQLITE3 stuff - get parameters for selected ellipsoid
//
sqlite3 *myDatabase;
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( QgsApplication::srsDbFilePath().toUtf8().data(), &myDatabase );
if ( myResult )
{
QgsMessageLog::logMessage( QObject::tr( "Can't open database: %1" ).arg( sqlite3_errmsg( myDatabase ) ) );
// XXX This will likely never happen since on open, sqlite creates the
// database if it does not exist.
return false;
}
// Set up the query to retrieve the projection information needed to populate the ELLIPSOID list
QString mySql = "select radius, parameter2 from tbl_ellipsoid where acronym='" + ellipsoid + "'";
myResult = sqlite3_prepare( myDatabase, mySql.toUtf8(), mySql.toUtf8().length(), &myPreparedStatement, &myTail );
// XXX Need to free memory from the error msg if one is set
if ( myResult == SQLITE_OK )
{
if ( sqlite3_step( myPreparedStatement ) == SQLITE_ROW )
{
radius = QString(( char * )sqlite3_column_text( myPreparedStatement, 0 ) );
parameter2 = QString(( char * )sqlite3_column_text( myPreparedStatement, 1 ) );
}
}
// close the sqlite3 statement
sqlite3_finalize( myPreparedStatement );
sqlite3_close( myDatabase );
// row for this ellipsoid wasn't found?
if ( radius.isEmpty() || parameter2.isEmpty() )
{
QgsDebugMsg( QString( "setEllipsoid: no row in tbl_ellipsoid for acronym '%1'" ).arg( ellipsoid ) );
return false;
}
// get major semiaxis
if ( radius.left( 2 ) == "a=" )
mSemiMajor = radius.mid( 2 ).toDouble();
else
{
QgsDebugMsg( QString( "setEllipsoid: wrong format of radius field: '%1'" ).arg( radius ) );
return false;
}
// get second parameter
// one of values 'b' or 'f' is in field parameter2
// second one must be computed using formula: invf = a/(a-b)
if ( parameter2.left( 2 ) == "b=" )
{
mSemiMinor = parameter2.mid( 2 ).toDouble();
mInvFlattening = mSemiMajor / ( mSemiMajor - mSemiMinor );
}
else if ( parameter2.left( 3 ) == "rf=" )
{
mInvFlattening = parameter2.mid( 3 ).toDouble();
mSemiMinor = mSemiMajor - ( mInvFlattening / mSemiMajor );
}
else
{
QgsDebugMsg( QString( "setEllipsoid: wrong format of parameter2 field: '%1'" ).arg( parameter2 ) );
return false;
}
QgsDebugMsg( QString( "setEllipsoid: a=%1, b=%2, 1/f=%3" ).arg( mSemiMajor ).arg( mSemiMinor ).arg( mInvFlattening ) );
// get spatial ref system for ellipsoid
QString proj4 = "+proj=longlat +ellps=" + ellipsoid + " +no_defs";
QgsCoordinateReferenceSystem destCRS;
destCRS.createFromProj4( proj4 );
// set transformation from project CRS to ellipsoid coordinates
mCoordTransform->setDestCRS( destCRS );
// precalculate some values for area calculations
computeAreaInit();
mEllipsoid = ellipsoid;
return true;
}
bool QgsDistanceArea::setEllipsoid( const QString& ellipsoid )
{
// Shortcut if ellipsoid is none.
if ( ellipsoid == GEO_NONE )
{
mEllipsoid = GEO_NONE;
return true;
}
// Check if we have a custom projection, and set from text string.
// Format is "PARAMETER:<semi-major axis>:<semi minor axis>
// Numbers must be with (optional) decimal point and no other separators (C locale)
// Distances in meters. Flattening is calculated.
if ( ellipsoid.startsWith( "PARAMETER" ) )
{
QStringList paramList = ellipsoid.split( ":" );
bool semiMajorOk, semiMinorOk;
double semiMajor = paramList[1].toDouble( & semiMajorOk );
double semiMinor = paramList[2].toDouble( & semiMinorOk );
if ( semiMajorOk && semiMinorOk )
{
return setEllipsoid( semiMajor, semiMinor );
}
else
{
return false;
}
}
// Continue with PROJ.4 list of ellipsoids.
QgsEllipsoidCache::Params params = QgsEllipsoidCache::instance()->getParams( ellipsoid );
// row for this ellipsoid wasn't found?
if ( params.radius.isEmpty() || params.parameter2.isEmpty() )
{
QgsDebugMsg( QString( "setEllipsoid: no row in tbl_ellipsoid for acronym '%1'" ).arg( ellipsoid ) );
return false;
}
// get major semiaxis
if ( params.radius.left( 2 ) == "a=" )
mSemiMajor = params.radius.mid( 2 ).toDouble();
else
{
QgsDebugMsg( QString( "setEllipsoid: wrong format of radius field: '%1'" ).arg( params.radius ) );
return false;
}
// get second parameter
// one of values 'b' or 'f' is in field parameter2
// second one must be computed using formula: invf = a/(a-b)
if ( params.parameter2.left( 2 ) == "b=" )
{
mSemiMinor = params.parameter2.mid( 2 ).toDouble();
mInvFlattening = mSemiMajor / ( mSemiMajor - mSemiMinor );
}
else if ( params.parameter2.left( 3 ) == "rf=" )
{
mInvFlattening = params.parameter2.mid( 3 ).toDouble();
mSemiMinor = mSemiMajor - ( mSemiMajor / mInvFlattening );
}
else
{
QgsDebugMsg( QString( "setEllipsoid: wrong format of parameter2 field: '%1'" ).arg( params.parameter2 ) );
return false;
}
QgsDebugMsg( QString( "setEllipsoid: a=%1, b=%2, 1/f=%3" ).arg( mSemiMajor ).arg( mSemiMinor ).arg( mInvFlattening ) );
// get spatial ref system for ellipsoid
QString proj4 = "+proj=longlat +ellps=" + ellipsoid + " +no_defs";
QgsCoordinateReferenceSystem destCRS = QgsCRSCache::instance()->crsByProj4( proj4 );
//TODO: createFromProj4 used to save to the user database any new CRS
// this behavior was changed in order to separate creation and saving.
// Not sure if it necessary to save it here, should be checked by someone
// familiar with the code (should also give a more descriptive name to the generated CRS)
if ( destCRS.srsid() == 0 )
{
QString myName = QString( " * %1 (%2)" )
.arg( QObject::tr( "Generated CRS", "A CRS automatically generated from layer info get this prefix for description" ) )
.arg( destCRS.toProj4() );
destCRS.saveAsUserCRS( myName );
}
//
// set transformation from project CRS to ellipsoid coordinates
mCoordTransform->setDestCRS( destCRS );
mEllipsoid = ellipsoid;
// precalculate some values for area calculations
computeAreaInit();
return true;
}
