问题描述
我的工作Java中的地理项目。
I am working on a geographic project in Java.
输入的坐标:24.4444ñ等输出:一个PLAIN地图(不圆)表示的坐标的点
The input are coordinates : 24.4444 N etcOutput: a PLAIN map (not round) showing the point of the coordinates.
我不知道该算法的坐标变换的x,y的一个JComponent,有人可以帮我吗?
I don't know the algorithm to transform from coordinates to x,y on a JComponent, can somebody help me?
在地图上看起来是这样的: http://upload.wikimedia.org/wikipedia/commons/7 /74/Mercator-projection.jpg
The map looks like this:http://upload.wikimedia.org/wikipedia/commons/7/74/Mercator-projection.jpg
感谢您
推荐答案
鉴于你的疏例如,您输入的范围将是(90.0N - 90.0S)和(180W - 180E)。这是最简单的 - 标准 - 如果转换的南部和西部,以底片给你的(90.0 ..- 90.0),纬度和(180.0 ..- 180.0)经度
Given your sparse example, the range of your inputs will be (90.0N - 90.0S) and (180W - 180E). It is easiest - and standard - if you convert South and West to negatives giving you latitudes of (90.0..-90.0) and longitudes of (180.0..-180.0).
由于画布的大小 - 让我们说这是140x120像素 - 你:
Given the size of your canvas - let's say it is 140x120 pixels - you get:
x = (latitude * canvas_height / 180.0) + (canvas_height / 2)
y = (longitude * canvas_width / 360.0) + (canvas_width / 2)
或
x = (longitude * 120.0 / 180.0) + (120/2)
y = (latitude * 140.0 / 360.0) + (140/2)
在哪里我已命令操作,以尽量减少舍入误差。这假定画布具有点(0,0)在左上角,或者,如果没有,你是澳大利亚
where I have ordered the operations to minimize rounding error. This assumes the canvas has point (0,0) in the upper-left or, if not, that you are Australian.
添加:您刚才在有关墨卡托投影位扔让我简单的回答不正确(但可能仍然可以使用由你,如果你不真正关心的投影)
Added: you just threw in the bit about Mercator projections making my simple answer incorrect (but possibly still usable by you if you don't actually care about projection)
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