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斯潘4
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斯潘4
AIXMis the航空信息交换模型格式。FME supports reading and writing AIXM version 4.5 (XML) and AIXM version 5.1 (GML).AIXM 5.1写作要求FME 2014或更新版本。下面将介绍这些版本中的每一个。还包括编写AIXM5 Airports的示例。
AIXM 4.5 XML
AIXM 4.5 is a complex XML based format designed to supportAeronautical Information Services(AIS).AIXM 4.5 contains no explicit geometry but rather has is built on relationships between non-geometry features and those with geoLong and geoLat attributes.Given the complexities of the schema and the way that geographic information is stored,data conversions between typical GIS data and AIXM 4.5 involves many transformation steps and usually requires the assistance of FME experts and experts familiar with the intricacies of the AIXM data models.Reading AIXM 4.5 is straightforward,but only yields non-geometry features and point features derived from the geoLong and geoLat attribute values.Linear and area features that could be derived from parent object relationships are not generated.
AIXM 5取代了AIXM 4.5,是基于GML的。As such it is best thought of as a completely different format than 4.5.It also means that all the geometries are composed of valid GML constructs.GML objects can be read and written with existing GML libraries.这大大简化了使用AIXM数据以及在GIS和AIXM数据结构之间转换的过程。AIXM5 is still a very complex schema and so writing to this format will still require the support of experts familiar with the AIXM standard.读取aixm5.1是选择源数据集和选择aixm5读卡器的简单问题。Note that both AIXM 5.0 and 5.1 versions are supported.
读取aixm通常只需要指向源数据并选择aixm格式。如果轴的方向不正确,可能需要选择轴顺序。You may also choose to map complex properties as XML Fragments and then use flattening options (substitute empty string for list braces) to make it easier to map from multiple,nested elements to a relational structure such as in GIS.要保留XML结构,请将映射复杂属性的默认读取器设置为“嵌套属性”。For schema Show Feature Types from: 'Dataset only with attributes merged from schema' typically yields the best results.
要写入aixm5数据,添加一个AIXM5编写器并选择要写入的主题。FME将这些目标特征类型放在工作区上,基于AIXM模式。然后是FME数据重组和模式映射,以支持目标AIXM模式。Your first step will be to decide which destination feature types you want to write to.Its usually a good idea to start simple and choose a few element types.例如,if you are trying to create an airport AIXM dataset,你可以从跑道开始,以及支持它所需的功能类型。To do this,您需要添加aixm编写器,然后导入与跑道关联的所有功能类型。So you could start with writing to Runways,跑道测速仪,加上aixmbasicmessage,它是文档容器。Note that you cannot create user defined fields or feature types.You must import the destination schema and restructure your data to precisely match that.
To successfully accomplish this transformation,您需要根据所需字段了解AIXM模式要求,IDs,父母/子女关系,nillable fields etc.Typically AttributeCopiers are used to do schema field mapping,属性创建器用于定义默认值,and AttributeValueMapper for value mapping.SchemaMapper can do all of this across multiple feature types using external crosswalk tables stored in csv or excel tables.Then there is the challenge of constructing the correct geometry structures.GeometryPropertySetters are used to set the correct geometry names,像gml ou ids这样的特性,和聚合器来组装复杂的几何聚合。See the attached EU airports writing example.一个读取AIXM5数据并将其写回的工作区需要0个转换器。The AIXM5 reader / writer supports all the complexities required for AIXM such as embedded geometry traits (for ids material types etc),multiple geometries per feature,nested features,repeating elements,nillable elements.We have also streamlined the GUIs and workspace parameters to make them easier to use.Note that,if there is a new draft schema you wish to use,您可以用更新后的FME覆盖一个出厂的FME,或者使用GML编写器。请注意,GML读卡器将检查任何给定GML文件上的名称空间,并使用该名称空间确定要使用的读卡器,so the GML reader can be used to read AIXM data as well.FME的AIXM读写器也支持AIXM扩展,这些扩展通常由主要航空管理机构(例如FAA or EUROCONTROL).These add-on schemas can be referenced under the application schema parameter,and should themselves reference and be compatible with the AIXM parent schemas.
There is not much point in writing AIXM GML if you can't validate the output.在FME中,we use the XMLValidator transformer to do this.它使用Apache Xerces库进行验证,所以你知道结果是客观的。The easiest way to do this is create a new workspace,添加一个创建者,then the XMLValidator.将xmlvalidator指向要测试的XML文件和要针对其进行验证的aixm应用程序架构的xsd文件。Connect the output of XMLValidator to Loggers.Run the workspace and review the log to see if your XML is valid.If not you will get a full report listing the problems with your XML related to the AIXM schema.请注意,XMLvalidator也有一个仅限语法的验证模式。
当构建一个新的工作空间时,您首先会得到许多验证错误。To help work your way through this,its a good idea to limit your output to one or 2 features.
Some issues to look out for:
- make sure each feature and geometry has a unique id.
-gml_id必须以字母字符开头。A general recommendation is to use a short object type abbreviation to prefix the root feature gml_id.For example if your root id = 101,you could use ah_101 for the airport heliport feature gml_id,ahts_101 for airport heliport time slice gml_id,and aharp_101 for airport heliport time slice ARP point gml_id.
- as above,在大多数情况下,geometries need gml_ids too.
- define the correct parent / child id relationships between AIXMBasicMessage,and whatever elements you are writing.
- uppercase names may be required
- adding any missing / required attributes and geometry traits
- warning messages may say 'element not allowed' when in fact what it means is that you are missing an element that needs to come first,或未能写入所需的父元素。
通过选择任何AIXM5数据集并设置一个读写它的工作区来自己测试这个问题。在数据检查器中打开输出,查看输出中是否包含所有内容。然后检查以确保结果针对aixmbasicmessage.xsd进行验证。Note that if your output doesn't validate,the first thing to check is whether or not your input validates.如果输入数据无效,FME将不会自动修复。Also note that if you want to write to a particular AIXM theme,一个好的第一步仍然是获取一些样本数据。Then you can make an AIXM5 to AIXM5 workspace and log the result.This will show you the structure of the FME feature you need to generate in order to drive your AIXM5 GML writer.
The attached example which shows how to read INSPIRE Transport Network Aerodromes and write AIXM AirportHeliports.The attachment includes the source INSPIRE GML,工作区和输出aixm5 gml,so you can use this to try out the AIXM reader as well.
The workspace illustrates the main transformation steps needed to write AIXM (also described in the AIXM Writing section above):
Note: In addition to these steps,需要注意的是,源模式和目标模式(特征类型和属性数据模型)都是模式驱动的。也就是说,创建工作区时,必须从可用架构列表中选择架构,或者添加读写器。You cannot create any user defined fields or attributes since these will not be compliant with the AIXM schema.
Completed INSPIRE Aerodrome to AIXM AirportHeliport Workspace
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