FME's scheme and operation process for reading and writing cass data

FME读写cass数据的方案及操作流程

一.CASS数据转换（一）Read SouthCASS数据

南方CASS数据采用AutoCAD的DWG、DXFfile storage,用FME可以直接对DWG\DXF文件进行读取,但FME不能识别CASSExtended attribute information.在FME WorkBench中无法看到CASSField information of the data layer,但可以通过FME Viewer中的“autocad_extended_data_list{}”properties to see this information.

图1

 

However, it is necessary to process the attribute information that is put into the list,却是一件很麻烦的事情,We had to adopt it by hand“List Transformers”Treat each field individually,Or manually create corresponding attribute fields in the target layer,A lot of time is wasted on the connection operation.If there are many layers or fields to be converted,The situation could get worse.

 

MyFME提供一个CASS插件来解决这些问题,将CASSThe extension information of the file is parsed as FMEThe recognized field structure（注：When there are no fields in the source data layer,MyFMEA file named “SOUTH”的字段）.Pass the parsed field information,The process becomes much easier,Users can directly operate on these fields,Or quickly generate the field structure of the target data layer.

 

图2

 

同时,MyFMEAttribute values ​​are automatically read,and associated with the corresponding field name.

图3

 

下图为CASSraw data in the software：

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MyFME目前只针对CASSThe extended attributes of the data file is read for processing,Graphics reading is still usedFME读取AutoCAD的方式,its related options and AutoCAD Readeroptions remain the same,Please refer to the description of the optionsFMEhelp file.

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二.CASS数据转换（二）南方CASS数据输出

和南方CASSThe extended information of the file is read similarly,用FMEDirect output to the southCASSAttribute information is also cumbersome.大致的思路是,设置AutoCAD Writer的“Attribute Output”选项为“Extended Entity Data”,并设置“Default Application Name”选项为“SOUTH”,Then add the attribute field write in the target layerCASS编码;It needs to be removed after the conversion is completeFMEAdded attribute value prefix.And this conversion scheme can only write a valid oneCASS属性字段,Most of the time we will“Default Application Name”设置为“SOUTH”,写入CASS的编码.

图1

 

MyFME提供CASSThe plug-in directly outputs attribute data in other formats as executablesCASSIdentified extended attributes,Simplify user transitions,Minimize post-processing work on transformed data;MyFME在输出CASSIn general, no additional setup and processing are required for the data,The source and target data can be directly converted after corresponding.The figure below shows thatSHAPEThe data file output isCASS数据文件.

图2

 

MyFME约定CASSThe attribute name in the target layer is “SOUTH”Field stores SouthCASS的编码信息,User must be validCASSThe encoded value is written to“SOUTH”字段（如图2所示）,for the SouthCASSThe software correctly identifies the feature type;The rest of the fields can be defined by the user as needed.CASSThe software opens the converted data.

图3

 

MyFME目前只针对CASSThe conversion of attribute information is processed,Graphical output is still usedFME的输出AutoCAD文件的方式,Output options and AutoCAD Writer保持一致,但“Default Application Name”选项无效,MyFMEThis option set by the user will be ignored.

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和FME输出AutoCAD文件相同,用户采用MyFME输出CASS文件时可以选择CAD文件版本,And allows the user to choose a custom template file（注：The user-defined template file must fully contain the output data layer and conformanceCASSDefinition of extended attributes）.

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三.CASS数据转换（三）Process attribute arrays

Reading SouthCASS数据时,我们发现存在“属性数组”,i.e. a field name,Contains a set of attribute values.FME Viewer中显示如下：

图1

 

 

南方CASSView the raw data in the software as follows：

图2

 

 

MyFME将这类“属性数组”Maps directly to attribute fields,并约定以“CASS_EX_”为前缀,以上数据在FME WordBench中显示如下.

图3

 

“SOUTH”Attribute fields are stored in total4个属性值（图1）,where the first property value maps to“SOUTH”字段,Subsequent values ​​are mapped to “CASS_EX_1”、“CASS_EX_2”、“CASS_EX_3”.读取到FME Viewer中显示如下图：

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向CASS数据文件写入“属性数组”时,Need to create a new one in the target layer“CASS_EX_”prefixed fields,You can arrange them in order to the corresponding attribute fields.The image below writes a file named “INFO”的字段,This field contains three attribute values.

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Used after conversion is completeFME Viewer查看数据如下：

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四.CASS数据转换（四）CASS数据分层

FME在读取CASS数据时,默认用AutoCADThe layer name to divide the feature layer：

图1

 

 

CASSElement identification is performed by a predetermined code,In order to better classify the elements,MyFME在CASSReader中提供Group Entities By选项,让FME在读取CASSelement time,按照CASSCoding for layer division.如图2所示,选择"CASS Code"表示用CASSCoding is layered,"Layer Name"It means layering by layer name.

图2

 

 

采用CASSAfter coding layering,The layer will be adoptedCASSEncoding class name,无CASSThe encoded features are uniformly divided into layers"none"中进行输出.

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采用CASSThe encoded hierarchical data output is as follows：

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