Yes it is. Either use the Mapguide API or write the code for the formula for
your state plane coordinates. Considering the formulas are quite tedious, I
say use the MgCoordinateSystemFactory class.
Example: LL84 to CA83-VF (Los Angeles)
function transformCoordinate($source, $target, $x, $y) {
//converts a coordinate from the source to the target
coordinate sytem,
needs site connection first
$coordSysFactory = new MgCoordinateSystemFactory();
$coordSys1 = $coordSysFactory->CreateFromCode($source);
$coordSys2 = $coordSysFactory->CreateFromCode($target);
$csTransform12 = $coordSysFactory->GetTransform($coordSys1,
$coordSys2);
$csTransform21 = $coordSysFactory->GetTransform($coordSys2,
$coordSys1);
$geometryFactory = new MgGeometryFactory();
//echo "Coordinates in CA83-VF: ($x, $y)<br>";
$coordinateArg = $geometryFactory->CreateCoordinateXY($x, $y);
$coordinate12 = $csTransform12->Transform($coordinateArg);
$x12 = $coordinate12->GetX();
$y12 = $coordinate12->GetY();
//echo "Coordinates in LL84: ($x12, $y12)<br>";
$new_coordinate = $geometryFactory->CreateCoordinateXY($x12,
$y12);
return $new_coordinate;
}
$lat = $args["lat"];
$lon = $args["lon"];
try {
MgInitializeWebTier($webconfigFilePath);
$userInfo = new MgUserInformation("e7", "e7");
$siteConnection = new MgSiteConnection();
$siteConnection->Open($userInfo);
$point = transformCoordinate("LL84", "CA83-VF", $lon, $lat);
echo $point->GetX() . "," . $point->GetY();
}
catch (MgException $e){
$errorMsg = $e->GetMessage();
$errorDetail = $e->GetDetails();
echo "$errorMsg: $errorDetail";
}
The same result using a formula:
class Point {
function __construct($x, $y) {
$this->X = $x;
$this->Y = $y;
}
}
function calculate ($t, $e, $p) {
//returns calculated expression
$num = 1 - $e*sin($p);
$den = 1 + $e*sin($p);
$den2 = pow($num/$den, $e/2);
$x = $t/$den2;
return $x;
}
function latAndLonToSP ($lat, $lon) {
//convert lat/lon to CA83-VF coordinates
$a = 20925604.4742; //major radius of ellipsoid, (NAD 83) CA
ZONE 0405
(feet), by definition
$e = 0.081819191042830; //eccentricity of ellipsoid (NAD 83)
CA ZONE 0405
$angRad = 0.01745329252; //number of radians in a degree
$pi4 = 3.1415926535897932384626433832795028841971/4; //Pi:4
$p0 = 33.5000 * $angRad; //latitude of origin, Bb
$m0 = -118.0000 * $angRad; //central meridian, Lo
$p1 = 34.03333333333333 * $angRad; //latitude of first
standard
parallel, Bs
$p2 = 35.46666666666666 * $angRad; //latitude of second
standard
parallel, Bn
$X0 = 6561666.66666666667; //False easting of central meridian
(feet), Eo
$Y0 = 1640416.66666666667; //False Northing of central meridian
(feet), Nb
//Calculate the coordinate system constants
$m1 = cos($p1) / sqrt(1 - ($e * $e * sin($p1) * sin($p1)));
$m2 = cos($p2) / sqrt(1 - ($e * $e * sin($p2) * sin($p2)));
$t0 = tan($pi4 - ($p0 / 2));
$t1 = tan($pi4 - ($p1 / 2));
$t2 = tan($pi4 - ($p2 / 2));
$t0 = calculate($t0, $e, $p0);
$t1 = calculate($t1, $e, $p1);
$t2 = calculate($t2, $e, $p2);
$n = log($m1 / $m2) / log($t1 / $t2);
$f = $m1 / ($n * pow($t1, $n));
$rho0 = $a * $f * pow($t0, $n);
//Convert the latitude/longitude to a coordinate.
$lat = $lat * $angRad;
$lon = $lon * $angRad;
$t = tan($pi4 - ($lat / 2));
$t = calculate($t, $e, $lat);
$rho = $a * $f * pow($t, $n);
$theta = $n * ($lon - $m0);
//false easting
$x = $rho * sin($theta) + $X0;
//false northing
$y = $rho0 - ($rho * cos($theta)) + $Y0;
//format to 6 decimals
$x = number_format($x, 6, '.', '');
$y = number_format($y, 6, '.', '');
$point = new Point($x, $y);
return $point;
}
$lat = $args["lat"];
$lon = $args["lon"];
$point = latAndLonToSP($lat, $lon);
$x = (string) $point->X;
$y = (string) $point->Y;
--
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