我正在创建一个Android应用程序(使用Java),该应用程序将从文件中读取SWEREF99TM坐标,并将其转换为WGS84(long-lat)坐标,并沿oposite方向。为此,我将使用JMapProjLib、Proj4j或Proj4js(我将使用Java的ScriptEngine
访问的JavaScript库)。
问题是我不知道如何使用这些库,因为文档太少了
我尝试过JMapProjLib-JavaLibrary,但它没有给我正确的结果,我也尝试过使用Proj4js 2.3.3,但我甚至无法获得后面提到的工作。。。
我目前正在使用的JavaScript(和一点HTML)代码,带有Proj4js 2.3.3(目前我只在HTML文件中尝试这个脚本,所以当转换完成时,浏览器应该显示一条弹出消息,说"完成!"):
<!DOCTYPE html>
<html>
<head>
<title>Proj4js Testing</title>
</head>
<body onload="convertCoordinates()">
<script type"text/javascript" src="proj4js.js"></script>
<script type="text/javascript">
// Convert coordinates
function convertCoordinates()
// Define the target projection (SWEREF99 TM)
var targetProjection = "+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs";
// Convert the WGS84 coordinates Lon: 15 and Lat: 55 to SWEREF99 TM coordinates
proj4(targetProjection, [15, 55]);
// Just show an alert message telling that the code has executed properly
alert("Done!");
}
</script>
</body>
</html>
我正在尝试的Java代码(使用JMapProjLib):
/**
* Convert a long-lat coordinate to a SWEREF99 TM coordinate.
*
* @param longLatCoordinate The long-lat coordinate to convert.
*
* @return The converted SWEREF99 TM coordinate.
*/
public static SWEREF99TMCoordinate longLatToSWEREF99TM(LongLatCoordinate longLatCoordinate) {
// Create a new SWEREF99 TM projection
Projection projection = ProjectionFactory.fromPROJ4Specification(new String[] {
"+proj=tmerc",
"+zone=33",
"+ellps=GRS80",
"+towgs84=0,0,0,0,0,0,0",
"+units=m",
"+no_defs"
});
// Convert the LongLatCoordinate to a Point2D.Double
Point2D.Double longLatPoint = new Point2D.Double(longLatCoordinate.getLongitude(), longLatCoordinate.getLatitude());
// Get the location as a SWEREF99 TM Point2D.Double
Point2D.Double sweref99TMPoint = projection.transform(longLatPoint, new Point2D.Double());
// COnvert the location to a SWEREF99TMCoordinate
SWEREF99TMCoordinate sweref99TMCoordinate = new SWEREF99TMCoordinate(sweref99TMPoint.x, sweref99TMPoint.y);
// Return the projected coordinate
return sweref99TMCoordinate;
}
引用到我的Java项目的JMapProjLib-库由git存储库中文件夹src/com/jhlabs/map
和src/coordsys/
中的内容组成,该存储库由我使用Eclipse编译为.jar
文件。
由于JavaScript-库Proj4js在我看来更"出色",我更喜欢将其与Java ScriptEngine
结合使用,所以我现在真正需要的只是某种文档,或者可以向我解释这一点的人。
您可以检查此存储库并提取您需要的内容:
https://github.com/dsegerss/Sonardrone/tree/master/src/org/sonardrone/proj/positions