src/projCode/Aea.php
public function phi1z($eccent, $qs)
    {
        $phi = Common::asinz(0.5 * $qs);

        if ($eccent < Common::EPSLN) {
            return $phi;
        }

        $eccnts = $eccent * $eccent;

        for ($i = 1; $i <= 25; ++$i) {
            $sinphi = sin($phi);
            $cosphi = cos($phi);
            $con = $eccent * $sinphi;
            $com = 1.0 - $con * $con;
            $dphi = 0.5 * $com * $com / $cosphi * ($qs / (1.0 - $eccnts) - $sinphi / $com + 0.5 / $eccent * log((1.0 - $con) / (1.0 + $con)));
            $phi = $phi + $dphi;

            if (abs($dphi) <= 1e-7) {
                return $phi;
            }
        }

        Proj4php::reportError("aea:phi1z:Convergence error");

        return null;
    }
public function phi1z($eccent, $qs)
    {
        $phi = Common::asinz(0.5 * $qs);

        if ($eccent < Common::EPSLN) {
            return $phi;
        }

        $eccnts = $eccent * $eccent;

        for ($i = 1; $i <= 25; ++$i) {
            $sinphi = sin($phi);
            $cosphi = cos($phi);
            $con = $eccent * $sinphi;
            $com = 1.0 - $con * $con;
            $dphi = 0.5 * $com * $com / $cosphi * ($qs / (1.0 - $eccnts) - $sinphi / $com + 0.5 / $eccent * log((1.0 - $con) / (1.0 + $con)));
            $phi = $phi + $dphi;

            if (abs($dphi) <= 1e-7) {
                return $phi;
            }
        }

        Proj4php::reportError("aea:phi1z:Convergence error");

        return null;
    }
public function phi1z ( $ eccent , $ qs ) { $ phi = Common :: asinz ( 0.5 * $ qs ) ; if ( $ eccent < Common :: EPSLN ) { return $ phi ; } $ eccnts = $ eccent * $ eccent ; for ( $ i = 1 ; $ i <= 25 ; ++ $ i ) { $ sinphi = sin ( $ phi ) ; $ cosphi = cos ( $ phi ) ; $ con = $ eccent * $ sinphi ; $ com = 1.0 - $ con * $ con ; $ dphi = 0.5 * $ com * $ com / $ cosphi * ( $ qs / ( 1.0 - $ eccnts ) - $ sinphi / $ com + 0.5 / $ eccent * log ( ( 1.0 - $ con ) / ( 1.0 + $ con ) ) ) ; $ phi = $ phi + $ dphi ; if ( abs ( $ dphi ) <= 1e-7 ) { return $ phi ; } } Proj4php :: reportError ( "aea:phi1z:Convergence error" ) ; return null ; }
Function to compute phi1, the latitude for the inverse of the Albers Conical Equal-Area projection.

@param float $eccent
@param float $qs
@return float|null on Convergence error
Function to compute phi1 the latitude for the inverse of the Albers Conical Equal - Area projection .