com.github.tsingjyujing.geo.basic.operations.GeoTransformable.scala Maven / Gradle / Ivy

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package com.github.tsingjyujing.geo.basic.operations

import com.github.tsingjyujing.geo.basic.IGeoPoint
import com.github.tsingjyujing.geo.element.mutable.GeoPoint

/**
  * For Chinese only
  * 注意转换后坐标的逆转换在一些国家和地区是违法的
  * 我愿意对自己的代码承担风险
  * 但是该逆转方法也不能保证全局都能做到无误差，也不保证所有的逆向方法都有效
  * 因为部分加密方法存在一定的信息损失，这些损失不一定能恢复
  * 在生效区域全局都是单射单变量复函数的加密方法在本函数面前都是渣渣
  * 如果坐标形式和经纬度差距太大可以采用线性回归变为近似线性以后再利用本方法
  *
  * @author [email protected]
  * @since 2.3
  * @version 1.0
  */
trait GeoTransformable {

    /**
      *
      * Must override this function to transform position
      * Encrypt WGS84 location to other type of coordinate
      *
      * @param x WGS84 position
      * @return
      */
    def transform(x: IGeoPoint): IGeoPoint

    /**
      * auto reverse transform of the position, need position has a goot ability of local-liner
      *
      * @param y transformed location
      * @return
      */
    def inverseTransformFast(y: IGeoPoint): GeoPoint = {
        val ffx = transform(y)
        GeoPoint(
            y.getLongitude * 2 - ffx.getLongitude,
            y.getLatitude * 2 - ffx.getLatitude
        )
    }

    /**
      * use iter-function method to auto reverse position
      *
      * @param y transformed location
      * @return
      */
    def inverseTransform(y: IGeoPoint, eps: Double = 0.01): IGeoPoint = {
        var errorValue = Double.MaxValue
        var i = 0
        val returnValue = inverseTransformFast(y)
        do {
            val fcx = transform(returnValue)
            errorValue = fcx geoTo y
            returnValue.setLongitude(returnValue.getLongitude - fcx.getLongitude + y.getLongitude)
            returnValue.setLatitude(returnValue.getLatitude - fcx.getLatitude + y.getLatitude)
            i += 1
        } while (errorValue > eps || i >= 32)
        returnValue
    }
}