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mysql使用WKB函数创建Geometry(几何)值

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Jun 07, 2016 pm 04:20 PM

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mysql使用WKB函数创建Geometry(几何)值 MySQL提供了众多函数，它们将包含WKT表达式、或可选的空间参考系统ID(SRID)的BLOB作为输入参数。它们返回对应的几何对象。 GeomFromWKB()接受任何几何类型的WKB作为其第1个参量。在实施方案中也提供了与类型相关的构造

　　mysql使用WKB函数创建Geometry(几何)值

　　MySQL提供了众多函数，它们将包含WKT表达式、或可选的空间参考系统ID(SRID)的BLOB作为输入参数。它们返回对应的几何对象。

　　GeomFromWKB()接受任何几何类型的WKB作为其第1个参量。在实施方案中也提供了与类型相关的构造函数，用于构造每一种几何类型的几何值。

　　GeomCollFromWKB(wkb[,srid]) , GeometryCollectionFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造GEOMETRYCOLLECTION值。

　　GeomFromWKB(wkb[,srid]) , GeometryFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造任意类型的几何值。

　　LineFromWKB(wkb[,srid]) , LineStringFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造LINESTRING值。

　　MLineFromWKB(wkb[,srid]) , MultiLineStringFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造MULTILINESTRING值。

　　MPointFromWKB(wkb[,srid]) , MultiPointFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造MULTIPOINT值。

　　MPolyFromWKB(wkb[,srid]) , MultiPolygonFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造MULTIPOLYGON值。

　　PointFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造POINT值。

　　PolyFromWKB(wkb[,srid]) , PolygonFromWKB(wkb[,srid])

　　使用其WKB表示和SRID构造POLYGON值。

　　OpenGIS规范还介绍了用于构造Polygon或MultiPolygon值的可选函数，这些值基于环和封闭LineString值集合的WKB表达式。这些值可以相交。MySQL未实施下述函数：

　　BdMPolyFromWKB(wkb,srid)

　　以包含已关闭LineString值任意集合的WKB格式，从MultiLineString值构造MultiPolygon值。

　　BdPolyFromWKB(wkb,srid)

　　以包含已关闭LineString值任意集合的WKB格式，，从MultiLineString值构造Polygon值。

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