Geometry是Esri geometry api中所有类的父类，它定义了所有几何数据的存储结构 与 基本方法。
无论派生出的任何点、线、面等要素都要遵循Geometry定下的基本规则，那我们就来看一下Geometry到底使用了什么思路？搭建了什么样的结构？
上图是Esri Geometry的子类们，与下图OGC 对Geometry 的定义相对比，Esri 使用顶点Vertex(并非是Point)来构建多点的要素，先将“多点要素”、“域”、“线” 和 “单点要素”分开，再构成其他要素。
Geometry一般包含的数据：
在Esri Geometry中每个几何实体都包含着：
VertexDescription m_description;//属性描述
volatile int m_touchFlag;//改动次数
其中VertexDescription用于存储各顶点的属性数据
而 m_touchFlag 则负责监视几何实体的改动操作
Geometry一般规定的操作：
在Esri Geometry中每个几何实体都可以：
对属性的操作（用的不多可跳过）：
addAttribute(int semantics) 加入属性
派生函数：addID() addM()
hasAttribute(int semantics) 查询属性
派生函数：hasID() hasM() hasZ()
dropAllAttributes() 删除所有附加属性(除了xy)
dropAttribute(int semantics) 删除某个属性
属性操作代码：
1 geomPoint.addAttribute(0);//无效，因为x是固有属性 2 geomPoint.addAttribute(1);//无效，因为y是固有属性 3 4 geomPoint.addAttribute(2);//添加M属性 5 geomPoint.addM();//等同于geomPoint.addAttribute(2); 6 geomPoint.addAttribute(3);//添加ID属性 7 geomPoint.addID();//等同于geomPoint.addAttribute(3); 8 9 System.out.println(geomPoint.hasAttribute(3));//检查是否有ID属性true 10 11 geomPoint.dropAttribute(3);//删除ID属性 12 System.out.println(geomPoint.hasAttribute(3));//检查是否有ID属性false 13 14 geomPoint.dropAllAttributes();//删除所有属性（XY固有属性除外） 15 System.out.println(geomPoint.hasAttribute(2));//检查是否有M属性false 16 System.out.println(geomPoint.hasAttribute(0));//检查是否有X属性true 固有属性不可删除
几何实体的几何判断*：
calculateLength2D() 计算长度 点：0 线：总线长 面：总线长
calculateArea2D() 计算面积 点：0 线：0 面：总面积
getBoundary() 得到边界 点：无 线：端点 面：所有边缘线(不分内外)
queryEnvelope(Envelope env) 得到外接矩形域
vertex_count(Geometry geom) 计算顶点个数
getDimension() 读取维度
getType() 读取类型
几何实体的几何判断代码：
System.out.println(geomPoint.calculateLength2D());
System.out.println(geomLine.calculateLength2D());
System.out.println(geomPolygon.calculateLength2D());
//计算长度
System.out.println(geomPoint.calculateArea2D()); System.out.println(geomLine.calculateArea2D());
System.out.println(geomPolygon.calculateArea2D());
//计算面积
Geometry geomTemp = geomPoint.getBoundary();
geomTemp = geomLine.getBoundary();
geomTemp = geomPolygon.getBoundary();
//得到边界
Envelope env1 = new Envelope();
geomPoint.queryEnvelope(env1);
System.out.println(env1.toString());
geomLine.queryEnvelope(env1);
System.out.println(env1.toString());
geomPolygon.queryEnvelope(env1);
System.out.println(env1.toString());
//得到外接矩形
System.out.println(Geometry.vertex_count(geomPoint));
System.out.println(Geometry.vertex_count(geomLine));
System.out.println(Geometry.vertex_count(geomPolygon));
//计算顶点个数
System.out.println(geomPoint.getDimension());
System.out.println(geomPoint.getType());
System.out.println(geomLine.getDimension());
System.out.println(geomLine.getType());
System.out.println(geomPolygon.getDimension());
System.out.println(geomPolygon.getType());
//读取维度/类型
其他操作：
copyTo(Geometry dst) 复制到另一个
createInstance() 新建一个同类型的空集
copy() 复制一个新的（ = copyTo + createInstance）
estimateMemorySize() 估计内存
setEmpty() 置空
isEmpty() 判断为空
toString() 输出string便于debug
其他操作代码：
wktString = "MULTIPOINT ((-106.4453583 41.11775),(-106.4453583 42.11775))";
Geometry geomMulitPoint2 = OperatorImportFromWkt.local().execute(WktImportFlags.wktImportDefaults, Geometry.Type.MultiPoint, wktString, null);
geomMulitPoint.copyTo(geomMulitPoint2);
System.out.println(geomMulitPoint.toString());
System.out.println(geomMulitPoint2.toString());
System.out.println(geomMulitPoint.isEmpty());
geomMulitPoint.setEmpty();
System.out.println(geomMulitPoint.isEmpty());
System.out.println(geomPoint.estimateMemorySize());
全部代码大家可以copy下来尝试：
1 package learn;
2
3 import java.io.IOException;
4
5 import org.codehaus.jackson.JsonParseException;
6
7 import com.esri.core.geometry.Geometry;
8 import com.esri.core.geometry.OperatorImportFromWkt;
9 import com.esri.core.geometry.Envelope;
10 import com.esri.core.geometry.WktImportFlags;
11
12 public class GeometryLearn {
13
14 public static void main(String args[]) throws IOException
15 {
16 createFromWKT();
17 }
18
19 static void createFromWKT() throws JsonParseException, IOException {
20
21
22 String wktString = "Point (-106.4453583 41.11775)";
23 Geometry geomPoint = OperatorImportFromWkt.local().execute(WktImportFlags.wktImportDefaults, Geometry.Type.Point, wktString, null);
24
25 wktString = "MULTIPOINT ((-106.4453583 39.11775),(-106.4453583 40.11775))";
26 Geometry geomMulitPoint = OperatorImportFromWkt.local().execute(WktImportFlags.wktImportDefaults, Geometry.Type.MultiPoint, wktString, null);
27
28 wktString = "MULTILINESTRING ((6.9 9.1,7 8.8),(6.8 8.8,7 9,7.2 8.9,7.4 9),(7.4 8.9,7.25 8.6,7.15 8.8))";
29 Geometry geomLine = OperatorImportFromWkt.local().execute(WktImportFlags.wktImportDefaults, Geometry.Type.Polyline, wktString, null);
30
31 wktString = "MULTIPOLYGON (((0.1 0.7, 0.1 0.4, 0.3 0.4, 0.3 0.7, 0.1 0.7)),"
32 + "((0 0, 0.5 0, 1 0.5, 0.5 1, 0 1, -0.5 0.5, 0 0),"
33 + "(0.5 0.2, 0.2 0.3, 0.1 0.2, -0.2 0.5, 0.2 0.9, 0.6 0.5, 0.5 0.2)))";
34 Geometry geomPolygon = OperatorImportFromWkt.local().execute(WktImportFlags.wktImportDefaults, Geometry.Type.Polygon, wktString, null);
35
36 geomPoint.addAttribute(0);
37 geomPoint.addAttribute(1);
38 geomPoint.addAttribute(2);
39 geomPoint.addM();
40 geomPoint.addAttribute(3);
41 geomPoint.addID();
42
43 System.out.println(geomPoint.hasAttribute(3));
44
45 geomPoint.dropAttribute(3);
46 System.out.println(geomPoint.hasAttribute(3));
47
48 geomPoint.dropAllAttributes();
49 System.out.println(geomPoint.hasAttribute(2));
50 System.out.println(geomPoint.hasAttribute(0));
51
52
53 // Geometry geomMulitPoint2 = geomMulitPoint.copy();
54 // System.out.println(geomMulitPoint2.toString());
55 //
56 // geomMulitPoint2.assignVertexDescription(geomMulitPoint.getDescription());
57 // System.out.println(geomMulitPoint2.toString());
58 //
59 // geomMulitPoint2.mergeVertexDescription(geomMulitPoint.getDescription());
60 // System.out.println(geomMulitPoint2.toString());
61
62
63 System.out.println(geomPoint.calculateLength2D());
64 System.out.println(geomLine.calculateLength2D());
65 System.out.println(geomPolygon.calculateLength2D());
66
67 System.out.println(geomPoint.calculateArea2D());
68 System.out.println(geomLine.calculateArea2D());
69 System.out.println(geomPolygon.calculateArea2D());
70
71
72 Geometry geomTemp = geomPoint.getBoundary();
73 geomTemp = geomLine.getBoundary();
74 geomTemp = geomPolygon.getBoundary();
75
76 Envelope env1 = new Envelope();
77 geomPoint.queryEnvelope(env1);
78 System.out.println(env1.toString());
79
80 geomLine.queryEnvelope(env1);
81 System.out.println(env1.toString());
82
83 geomPolygon.queryEnvelope(env1);
84 System.out.println(env1.toString());
85
86
87 System.out.println(Geometry.vertex_count(geomPoint));
88 System.out.println(Geometry.vertex_count(geomLine));
89 System.out.println(Geometry.vertex_count(geomPolygon));
90
91 System.out.println(geomPoint.getDimension());
92 System.out.println(geomPoint.getType());
93
94 System.out.println(geomLine.getDimension());
95 System.out.println(geomLine.getType());
96
97 System.out.println(geomPolygon.getDimension());
98 System.out.println(geomPolygon.getType());
99
100 wktString = "MULTIPOINT ((-106.4453583 41.11775),(-106.4453583 42.11775))";
101 Geometry geomMulitPoint2 = OperatorImportFromWkt.local().execute(WktImportFlags.wktImportDefaults, Geometry.Type.MultiPoint, wktString, null);
102
103 geomMulitPoint.copyTo(geomMulitPoint2);
104 System.out.println(geomMulitPoint.toString());
105 System.out.println(geomMulitPoint2.toString());
106
107 System.out.println(geomMulitPoint.isEmpty());
108 geomMulitPoint.setEmpty();
109 System.out.println(geomMulitPoint.isEmpty());
110 System.out.println(geomPoint.estimateMemorySize());
111
112 }
113 }
参考：
http://esri.github.io/geometry-api-java/javadoc/com/esri/core/geometry/Geometry.html
https://github.com/Esri/geometry-api-java/wiki
原文地址：https://www.cnblogs.com/17th-trackwalker/p/10338957.html
时间： 2024-11-13 06:57:50