确定点是否在边界框内

Question

您如何确定给定点是否在边界框内？

我的观点是48.847172,2.386597.

BoundingBox的:

    "48.7998602295",
    "48.8198640442",
    "2.46138595581",
    "2.48138619423"

Answer 1

像往常一样:

if( bb.ix <= p.x && p.x <= bb.ax && bb.iy <= p.y && p.y <= bb.ay ) {
    // Point is in bounding box
}

bb是边界框,(ix,iy)是它的左上角坐标,还是(ax,ay)它的右下角坐标. p是点和(x,y)它的坐标.

Answer 2

此解决方案还考虑了UI发送一个跨越经度180/-180的框的情况(在低缩放级别上映射视图,您可以看到整个世界,允许无限循环水平滚动,因此有可能例如一个方框的bottomLeft.lng = 170而topRight.lng = -170(= 190),其中包括20度的范围.

def inBoundingBox(bl/*bottom left*/: Coordinates, tr/*top right*/: Coordinates, p: Coordinates): Boolean = {
    // in case longitude 180 is inside the box
    val isLongInRange =
      if (tr.long < bl.long) {
        p.long >= bl.long || p.long <= tr.long
      } else
        p.long >= bl.long && p.long <= tr.long

    p.lat >= bl.lat  &&  p.lat <= tr.lat  &&  isLongInRange
}

Answer 3

如果您使用的是传单,则可以创建一个新的LatLngBounds并使用其contains()操作:

var bounds = new L.LatLngBounds(
 new L.LatLng(gc.bbox['_northEast'].lat, gc.bbox['_northEast'].lng),
 new L.LatLng(gc.bbox['_southWest'].lat, gc.bbox['_southWest'].lng));

return bounds.contains(new L.LatLng(pos.latitude, pos.longitude))

Answer 4

这个答案与上面 kumetix 的答案相同；然而，对于我的一生来说，我并不明白那里发生了什么，因为它被浓缩了很多。这是带有详细解释的相同答案。另请注意，答案是 Kotlin 语言，而不是原始帖子要求的 JavaScript 语言，但它具有足够的可读性，因此转换为您的语言应该不会太糟糕。

首先定义 Coordinate2D 和 BoundingBox 类：

data class Coordinate2D (val latitude: Double, val longitude: Double)

data class BoundingBox (val north: Double, val east: Double, val south: Double, val west: Double)

这是确定一个点是否在任意边界框中的函数

fun isPointInBoundingBox(point: Coordinate2D, boundingBox: BoundingBox): Boolean {
    //given the bounding box is an imaginary rectangle in a coordinate system
    //bounding box has 4 sides - northLine, eastLine, southLine and westLine
    //initially assume the point is not in our bounding box of interest as such:
    var isPointEastOfWestLine = false
    var isPointWestOfEastLine = false
    var isPointSouthOfNorthLine = false
    var isPointNorthOfSouthLine = false

    if (boundingBox.east < boundingBox.west) {
        //if west coordinate has a bigger value than the east, 
        //the bounding box must be crossing the dateline
        //in other words, longitude 180 is inside the box
        //let's see what's happening with the point
        if (point.longitude >= boundingBox.west) {
            //imagine a bounding box where westernmost longitude is +170 and easternmost longitude is -170
            //if the point in question has a latitude of +171 as in the case expressed in the if
            //statement, then we can conclude that point lies east of the west line
            isPointEastOfWestLine = true

            //we can also infer that the point must lie west of east line because the point's longitude is positive
            //therefore, the point's position must be to the west of the easternmost longitude of the bounding box
            isPointWestOfEastLine = true
        }

        if (point.longitude <= boundingBox.east) {
            //imagine a bounding box where westernmost longitude is +170 and easternmost longitude is -170
            //if the point in question has a latitude of -171 as in the case expressed in the if
            //statement, then we can conclude that point lies west of the east line
            isPointWestOfEastLine = true

            //we can also infer that the point must lie east of the west line because the point's longitude is negative
            //therefore, the point's position must be to the east of the westernmost longitude of the bounding box
            isPointEastOfWestLine = true
        }
    } else {
        //in the else case, bounding box does not cross the dateline, so comparisons are more straightforward
        //longitudes range from -180 to +180; therefore, western side of a bounding box will always
        //have lower value than eastern side
        if (point.longitude >= boundingBox.west) {
            //in this case, point's longitude has a higher value than the west side of the bounding box
            //we can conclude that point lies to the east of the west line of the bounding box
            isPointEastOfWestLine = true
        }
        if (point.longitude <= boundingBox.east) {
            //in this case, point's longitude has a lower value than the east side of the bounding box
            //we can conclude that point lies to the east of the west line of the bounding box
            isPointWestOfEastLine = true
        }
    }

    //comparing latitudes are little bit easier. latitude values range from -90 to +90 where
    //-90 is the southern pole and +90 is the northern pole. The more north you go, higher the values.
    if (point.latitude >= boundingBox.south) {
        //point's latitude is higher, therefore, point must lie to the north of the south line
        isPointNorthOfSouthLine = true
    }

    if (point.latitude <= boundingBox.north) {
        //point's latitude is higher, therefore, point must lie to the north of the south line
        isPointSouthOfNorthLine = true
    }

    return isPointEastOfWestLine &&
            isPointWestOfEastLine &&
            isPointNorthOfSouthLine &&
            isPointSouthOfNorthLine
}

Answer 5

这应该更快。

function doesPointCollide(p,box) {
    return !(p.x < box.left || p.x > box.right || p.y > box.bottom || p.y < box.top)
}

如果点在任何维度之外，我们知道它不在边界框中，否则它在边界框中，因此我们可以更快地忽略否定情况。