問題描述

這些是我選擇的對角線點的坐標(biāo)，選擇的點越多就會越多.

These are my coordinates of Selected diagonal points, will be more when selected points are more.

1: 25.312063043186914  2: 55.30672073364258
1: 25.24096949112138   2: 55.40525436401367
1: 25.224509592006314  2: 55.3462028503418
1: 25.22513076073063   2: 55.281314849853516
1: 25.27822894908031   2: 55.25899887084961

下面是我當(dāng)前的 mysql 查詢在選定的對角線之間沒有給我完美的結(jié)果.有幫助嗎??

below is my current mysql query not giving me perfect result between selected diagonal.any help??

SELECT 
  * 
FROM
  tbl_custom 
WHERE latitude <= 25.312063043186914 
  AND latitude >= 25.224509592006314 
  AND longitude <= 55.40525436401367 
  AND longitude >= 55.25899887084961 

推薦答案

要消除邊界框查詢內(nèi)但不在多邊形內(nèi)的點，您需要使用 多邊形中的點 算法.

To eliminate the points within your bounding box query but not within polygon you require to use Point in Polygon algorithm.

最簡單的方法是使用數(shù)組中的坐標(biāo).這些可用于查找查詢的最大和最小坐標(biāo)以及 pointInPolygon() 函數(shù)的參數(shù).

The easiest way to do this is to have the coordinates in arrays. These can be used to find max and min coordinates for the query and for parameters for pointInPolygon() function.

function pointInPolygon(polySides,polyX,polyY,x,y) {
 var j = polySides-1 ;
  oddNodes = 0;
  for (i=0; i<polySides; i++) {
    if (polyY[i]<y && polyY[j]>=y  ||  polyY[j]<y && polyY[i]>=y) {
        if (polyX[i]+(y-polyY[i])/(polyY[j]-polyY[i])*(polyX[j]-polyX[i])<x)  {
            oddNodes=!oddNodes; 
        }
    }
   j=i; }

  return oddNodes;
}

在您的地圖代碼中使用 jQuery getJSON()

In your Map code using jQuery getJSON()

var polySides = 4;//number of points in polygon
//horizontal Latitude coordinates of polygon  
var polyLat = new Array();
polyLat[0] = 51.5;
polyLat[1] = 51.5;
polyLat[2] = 52.5;
polyLat[3] = 53;
polyLat[4] = 51.5;//First point repeated to close polygon
//vertical Longitude coordinates of polygon 
var polyLng =  new Array();
polyLng[0] = 0.5;
polyLng[1] = -1.9;
polyLng[2] = -1;
polyLng[3] = 0.6;
polyLng[4] = 0.5;
//Coordinates for bounding box
var maxLat = Math.max.apply(null,polyLat);
var minLat = Math.min.apply(null,polyLat);
var maxLng = Math.max.apply(null,polyLng);
var minLng = Math.min.apply(null,polyLng);

//Using jQuery
var url = "yourFile .php";
 url +="?maxLat="+maxLat +"&minLat="+minLat +"&maxLng="+maxLng +"&minLng="+minLng;
 $.getJSON(url,function(data) {
    $.each(data.marker,function(i,dat){
        if (pointInPolygon(polySides,polyLat,polyLng,dat.lat,dat.lng)){
            var latlng = new google.maps.LatLng(dat.lat,dat.lng); 
            addMarker(latlng,dat.name);
            bounds.extend(latlng);
        }
    });
    map.fitBounds(bounds);
});

使用邊界框和多邊形中的點獲得的地圖.

Map obtained using Bounding Box and Point in Polygon.

這篇關(guān)于如何在mysql查詢中找到所選對角線區(qū)域之間的準(zhǔn)確數(shù)據(jù)的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網(wǎng)！