VFK-捷克地籍交换数据格式

司机简称

VFK

生成依赖项

libsqlite3

此驱动程序读取VFK文件，即 捷克地籍交换数据格式 . VFK文件被识别为具有零层或更多层的数据源。

只有当GDAL是 使用SQLite支持构建 .

点表示为wkbPoints，线和边界表示为wkblienstrings，区域表示为wkbPolygons。wkbMulti公司 * 不使用功能。不能在一个图层中混合要素类型。

驱动程序功能

Supports Georeferencing

This driver supports georeferencing

Supports VirtualIO

This driver supports virtual I/O operations (/vsimem/, etc.)

打开选项

从gdal2.3开始，可以指定以下打开选项（通常使用 -oo name=value ogrinfo或ogr2ogr的参数）：

  • SUPPRESS_GEOMETRY =是/否（默认为否）。将其设置为“是”将跳过解析几何体。所有图层都将被识别为没有几何图形类型。当用户只对属性感兴趣时最有用。注意，当驱动器读取输入的VFK数据时，抑制几何结构会导致显著的性能增益。

  • FILE_FIELD =是/否（默认为否）。设置为“是”将追加新字段 VFK_FILENAME 包含所有层的源VFK文件的名称。

配置选项

Several configuration options are available.

The driver uses SQLite as a backend database when reading VFK data. By default, SQLite database is created in a directory of input VFK file (with file extension '.db'). The user can define DB name with OGR_VFK_DB_NAME configuration option. If OGR_VFK_DB_OVERWRITE =YES configuration option is given, the driver overwrites existing SQLite database and stores data read from input VFK file into newly created DB. If OGR_VFK_DB_DELETE =YES configuration option is given, the driver deletes backend SQLite database when closing the datasource.

Resolved geometries are stored also in backend SQLite database. It means that geometries are resolved only once when building SQLite database from VFK data. Geometries are stored in WKB format. Note that GDAL doesn't need to be built with SpatiaLite support. Geometries are not stored in DB when OGR_VFK_DB_SPATIAL =NO configuration option is given. In this case geometries are resolved when reading data from DB on the fly.

内部工作和性能调整

如果后端SQLite数据库已经存在，那么驱动程序直接从数据库读取特性，而不是从作为输入数据源提供的输入VFK文件读取特性。这会在驱动程序读取功能时导致显著的性能提高。

The driver reads by default all data blocks from VFK file when building backend SQLite database. When configuration option OGR_VFK_DB_READ_ALL_BLOCKS =NO is given, the driver reads only data blocks which are requested by the user. This can be useful when the user want to process only part of VFK data.

数据源名称

数据源名称是VFK文件的完整路径。

驱动程序支持读取由VSI虚拟文件系统API管理的文件，这些文件包括“常规”文件以及/vsizip/、/vsigzip/和/vsicurl/只读域中的文件。

Since GDAL 2.2 also a full path to the backend SQLite database can be used as an datasource. By default, such datasource is read by SQLite driver. If configuration option OGR_VFK_DB_READ =YES is given, such datasource is opened by VFK driver instead.

图层名

VFK数据块用作图层名。

过滤器

属性过滤器

内部SQL引擎用于计算表达式。设置属性过滤器后，计算将执行一次。

空间滤波器

存储在拓扑结构中的特征的边界框用于评估特征是否与当前空间过滤器匹配。设置空间过滤器后，将执行一次计算。

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