GML 边界框中的纬度/经度信息答案

【问题标题】：latitude/longitude info in a GML Bounding boxGML 边界框中的纬度/经度信息
【发布时间】：2013-03-17 04:04:56
【问题描述】：

例如，如果我们在 gml 中有如下所示的边界框：

<gml:Envelope> <gml:lowerCorner>42.943 -71.032</gml:lowerCorner> <gml:upperCorner>43.039 -69.856</gml:upperCorner> </gml:Envelope>

现在，对于下角，哪个值是纬度，哪个是经度。在在线文档中找不到此信息。

谢谢流浪者

以上 GML 采用 GeoRSS 格式

【问题讨论】：

标签： latitude-longitude gml

【解决方案1】：

来自 GML 模式：

<complexType name="EnvelopeType">
<choice>
<sequence>
<element name="lowerCorner" type="gml:DirectPositionType"/>
<element name="upperCorner" type="gml:DirectPositionType"/>
</sequence>
<element ref="gml:pos" minOccurs="2" maxOccurs="2">
<annotation>
<appinfo>deprecated</appinfo>
</annotation>
</element>
<element ref="gml:coordinates"/>
</choice>
<attributeGroup ref="gml:SRSReferenceGroup"/>
</complexType>
<element name="Envelope" type="gml:EnvelopeType" substitutionGroup="gml:AbstractObject">
<annotation>
<documentation>
Envelope defines an extent using a pair of positions defining opposite corners in arbitrary dimensions. The first direct position is the "lower corner" (a coordinate position consisting of all the minimal ordinates for each dimension for all points within the envelope), the second one the "upper corner" (a coordinate position consisting of all the maximal ordinates for each dimension for all points within the envelope). The use of the properties "coordinates" and "pos" has been deprecated. The explicitly named properties "lowerCorner" and "upperCorner" shall be used instead.
</documentation>
</annotation>
</element>

这会导致 SRSReference 组，其中包含允许您查找坐标轴顺序和单位（以及其他内容）的代码。：

<attributeGroup name="SRSReferenceGroup">
<annotation>
<documentation>
The attribute group SRSReferenceGroup is an optional reference to the CRS used by this geometry, with optional additional information to simplify the processing of the coordinates when a more complete definition of the CRS is not needed. In general the attribute srsName points to a CRS instance of gml:AbstractCoordinateReferenceSystem. For well-known references it is not required that the CRS description exists at the location the URI points to. If no srsName attribute is given, the CRS shall be specified as part of the larger context this geometry element is part of.
</documentation>
</annotation>
<attribute name="srsName" type="anyURI"/>
<attribute name="srsDimension" type="positiveInteger"/>
<attributeGroup ref="gml:SRSInformationGroup"/>
</attributeGroup>

所以没有指定的 SRS 就不可能回答你的问题，我们甚至不知道你的坐标是什么单位。

【讨论】：