void OGRSOSIDataSource::buildOGRLineString(int nNumCoo, long iSerial) {
if (papoBuiltGeometries[iSerial] != NULL) {
return;
}
OGRLineString *poLS = new OGRLineString();
poLS->setNumPoints(nNumCoo);
long i;
double dfEast = 0, dfNorth = 0;
for (i=1; i<=nNumCoo; i++) {
LC_GetTK(i, &dfEast, &dfNorth);
poLS->setPoint(i-1, dfEast, dfNorth);
}
papoBuiltGeometries[iSerial] = poLS;
}
void OGRSOSIDataSource::buildOGRMultiPoint(int nNumCoo, long iSerial) {
if (papoBuiltGeometries[iSerial] != NULL) {
return;
}
OGRMultiPoint *poMP = new OGRMultiPoint();
long i;
double dfEast = 0, dfNorth = 0;
for (i=(nNumCoo>1)?2:1; i<=nNumCoo; i++) {
LC_GetTK(i, &dfEast, &dfNorth);
OGRPoint poP = OGRPoint(dfEast, dfNorth);
poMP->addGeometry(&poP); /*poP will be cloned before returning*/
}
papoBuiltGeometries[iSerial] = poMP;
}
void OGRSOSIDataSource::buildOGRPoint(long iSerial) {
double dfEast = 0, dfNorth = 0;
LC_GetTK(1, &dfEast, &dfNorth);
papoBuiltGeometries[iSerial] = new OGRPoint(dfEast, dfNorth);
}
void OGRSOSIDataSource::buildOGRLineStringFromArc(long iSerial) {
if (papoBuiltGeometries[iSerial] != NULL) {
return;
}
OGRLineString *poLS = new OGRLineString();
/* fetch reference points on circle (easting, northing) */
double e1 = 0, e2 = 0, e3 = 0;
double n1 = 0, n2 = 0, n3 = 0;
LC_GetTK(1, &e1, &n1);
LC_GetTK(2, &e2, &n2);
LC_GetTK(3, &e3, &n3);
/* helper constants */
double p12 = (e1 * e1 - e2 * e2 + n1 * n1 - n2 * n2) / 2;
double p13 = (e1 * e1 - e3 * e3 + n1 * n1 - n3 * n3) / 2;
double dE12 = e1 - e2;
double dE13 = e1 - e3;
double dN12 = n1 - n2;
double dN13 = n1 - n3;
/* center of the circle */
double cE = (dN13 * p12 - dN12 * p13) / (dE12 * dN13 - dN12 * dE13) ;
double cN = (dE13 * p12 - dE12 * p13) / (dN12 * dE13 - dE12 * dN13) ;
/* radius of the circle */
double r = sqrt(sqr(e1 - cE) + sqr(n1 - cN));
/* angles of points A and B (1 and 3) */
double th1 = atan2(n1 - cN, e1 - cE);
double th3 = atan2(n3 - cN, e3 - cE);
/* interpolation step in radians */
double dth = th3 - th1;
if (dth < 0) {dth += 2 * M_PI;}
if (dth > M_PI) {
dth = - 2*M_PI + dth;
}
int npt = (int)(ARC_INTERPOLATION_FULL_CIRCLE * dth / 2*M_PI);
if (npt < 0) npt=-npt;
if (npt < 3) npt=3;
poLS->setNumPoints(npt);
dth = dth / (npt-1);
long i;
double dfEast = 0, dfNorth = 0;
for (i=0; i<npt; i++) {
dfEast = cE + r * cos(th1 + dth * i);
dfNorth = cN + r * sin(th1 + dth * i);
if (dfEast != dfEast) { /* which is a wonderful property of nans */
CPLError( CE_Warning, CPLE_AppDefined,
"Calculated %lf for point %li of %i in curve %li.", dfEast, i, npt, iSerial);
}
poLS->setPoint(i, dfEast, dfNorth);
}
papoBuiltGeometries[iSerial] = poLS;
}