GIS基本算法--01判断点是否在线上

Author: OrdinarySK

.idea/inspectionProfiles/Project_Default.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

.idea/misc.xml

@@ -0,0 +1,59 @@
+package algo;
+
+/**
+ * @ClassName PointOnLine
+ * @Description 判断点是否在线上
+ * @Author luokai
+ * @CreateDate 2020/8/15 22:51
+ * @UPpdateUser luokai
+ * @UpdateDate 2020/8/15 22:51
+ * @UpdateRemark
+ * @Version 1.0
+ * Copyright (c) 2019,武汉中地云申科技有限公司
+ * All rights reserved.
+ **/
+
+/**
+ * 算法原理介绍
+ * 判断一个点是否在一条线上，其原理是利用叉积乘。a×b=|x1, y1|=x1y2-x2y1
+ *                                                |x2, y2|
+ * 例如点Q是否在线段p1和P2上  (Q-p1)✖(p2-p1) = 0
+ * 除此之外，还要保证该点在点p1  p2所连成的对角矩阵的内部  因为第一个条件满足的情况下  可能是p1p2的延长线上
+ *
+ *
+ */
+
+import entity.Point;
+
+public class PointOnLine {
+
+    public boolean PointOnLine(Point p1, Point p2, Point q ){
+        boolean flag = false;     // true   点在线上    false   点不在线上
+
+        if(((q.getLon()-p1.getLon()) * (p2.getLat()-p1.getLat()) - (q.getLat()-p1.getLat()) * (p2.getLon()-p1.getLon())) == 0){
+            //System.out.println("点在线上这条直线上");
+            if(p1.getLon() >= p2.getLon() && p1.getLat() >= p2.getLat()){
+                //点p1在点p2右上方    p1x > p2x p1y> p2y
+                if(q.getLon() <= p1.getLon() && q.getLon() >= p2.getLon() && q.getLat() <= p1.getLat() && q.getLat() >= p2.getLat()){
+                    flag = true;
+                }
+            }else if(p1.getLon() >= p2.getLon() && p1.getLat() <= p2.getLat()){
+                //点p1在点p2的右下方   p1x > p2x p1y < p2y
+                if(q.getLon() <= p1.getLon() && q.getLon() >= p2.getLon() && q.getLat() >= p1.getLat() && q.getLat() <= p2.getLat()){
+                    flag = true;
+                }
+            }else if(p1.getLon() <= p2.getLon() && p1.getLat() >= p2.getLat()){
+                //点p1在p2左上方   p1x < p2x p1y > p2y
+                if(q.getLon() >= p1.getLon() && q.getLon() <= p2.getLon() && q.getLat() <= p1.getLat() && q.getLat() >= p2.getLat()){
+                    flag = true;
+                }
+            }else if(p1.getLon() <= p2.getLon() && p1.getLat() <= p2.getLat()){
+                //点p1在p2左下方 p1x < p2x p1y < p2y
+                if(q.getLon() >= p1.getLon() && q.getLon() <= p2.getLon() && q.getLat() >= p1.getLat() && q.getLat() <= p2.getLat()){
+                    flag = true;
+                }
+            }
+        }
+        return flag;
+    }
+}

.idea/modules.xml

@@ -0,0 +1,41 @@
+package entity;
+
+/**
+ * @ClassName Point
+ * @Description 定义坐标点
+ * @Author luokai
+ * @CreateDate 2020/8/15 22:52
+ * @UPpdateUser luokai
+ * @UpdateDate 2020/8/15 22:52
+ * @UpdateRemark
+ * @Version 1.0
+ * Copyright (c) 2019,武汉中地云申科技有限公司
+ * All rights reserved.
+ **/
+public class Point {
+    public Point(double lon, double lat) {
+        this.lon = lon;
+        this.lat = lat;
+    }
+
+    //定义经纬度
+    private double lon;
+    private double lat;
+
+    public double getLon() {
+        return lon;
+    }
+
+    public void setLon(double lon) {
+        this.lon = lon;
+    }
+
+    public double getLat() {
+        return lat;
+    }
+
+    public void setLat(double lat) {
+        this.lat = lat;
+    }
+
+}

GIS_algorithm.iml

@@ -0,0 +1,31 @@
+package test;
+
+/**
+ * @ClassName Test01
+ * @Description TODO
+ * @Author luokai
+ * @CreateDate 2020/8/16 11:41
+ * @UPpdateUser luokai
+ * @UpdateDate 2020/8/16 11:41
+ * @UpdateRemark
+ * @Version 1.0
+ * Copyright (c) 2019,武汉中地云申科技有限公司
+ * All rights reserved.
+ **/
+import entity.Point;
+import algo.PointOnLine;
+public class Test01 {
+    public static void main(String args[]){
+        Point p1 = new Point(110,30);
+        Point p2 = new Point(115, 40);
+        Point q = new Point(112, 34);
+
+        PointOnLine pointOnLine = new PointOnLine();
+        boolean flag = pointOnLine.PointOnLine(p1, p2, q);
+        if(flag){
+            System.out.println("该点在线上");
+        }else{
+            System.out.println("该点不在线上");
+        }
+    }
+}