Esri geometry api java 学习文档 (2) 几何图形 (Geometry)与数据结构

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用于存储各顶点的数据与属性

　　　　　　(点元素直接用它（m_description = VertexDescriptionDesignerImpl.getDefaultDescriptor2D();），

　　　　　　其他类都自定义m_impl存储数据中也都会有类似语句 )

　　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

　　坐标转换(二维仿射变换)：

　　　　　Transformation2D transformation = new Transformation2D();

　　　　　geomPoint.applyTransformation( transformation );

　　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

posted @ 2019-02-11 20:32 第17个巡道工阅读(1909) 评论(0) 编辑收藏举报

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Esri geometry api java 学习文档 (2) 几何图形 (Geometry)与数据结构

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