The directives that are processed by the OS(GB) NTF reader are listed below. The suffixes shown are prefixed by the current <ReaderKeyword> in a mapping file. By default, the <ReaderKeyword> for the OS(GB) NTF reader is NTF.
DATASET
This is the name of a folder containing one or more NTF files. Each NTF file must have an extension of .NTF.
Required/Optional
Required
Example
NTF_DATASET D:\DATA\LANDFORM
Workbench Parameter
Source OS (GB) NTF File(s)
IDs
Required/Optional
Optional
This optional specification is used to limit the available NTF files read. If no IDs are specified, then all available NTF files are read.
The syntax of the IDs keyword is:
<ReaderKeyword>_IDs <baseName1> \ <baseName2> ... \ <baseNameN>
The example below selects only the SS68.NTF file for input during a translation:
NTF_IDs SS68
FORCE_GENERIC
FME is programmed to recognize a set of standard Ordnance Survey NTF products and to provide a feature schema tailored to the data product, with field names appropriate to the data product. However, any NTF file not recognized as being a specifically targeted product profile, using the DBNAME field of the DBHREC record, is generically handled, at some cost to efficiency and tailoring of feature schema.
The FORCE_GENERIC directive can be used to force recognized products to be treated using the generic rules, rather than the product-specific rules. This could be useful if new versions of standard products are inappropriately treated by product-specific rules or if you desire that all features from different products be returned using a common, or generic, schema.
Required/Optional
Optional
Values
ON | OFF (default)
Mapping File Syntax
NTF_FORCE_GENERIC ON
DEM_SAMPLE
FME can read Land-Form PANORAMA™ and Land-Form PROFILE™ raster Digital Terrain Model (DTM) products, translating each pixel into a point feature. This can produce a lot of point features—160000 to 250000 per file. Sometimes it is desirable to extract only a sub-sample of the features, while maintaining a regular grid pattern of points.
The DEM_SAMPLE directive is used to specify a decimation factor that is applied in the horizontal and vertical directions. A DEM_SAMPLE value of 3, for instance, returns only one in three points in both horizontal and vertical directions from the reader, resulting in an 8/9ths reduction in the total number of features.
Required/Optional
Optional
Values
Default value: 1
Mapping File Syntax
NTF_DEM_SAMPLE 3
SEARCH_ENVELOPE
Using the minimum and maximum x and y parameters, define a bounding box that will be used to filter the input features. Only features that interact with the bounding box are returned.
If all four coordinates of the search envelope are specified as 0, the search envelope will be disabled.
Mapping File Syntax
<ReaderKeyword>_SEARCH_ENVELOPE <minX> <minY> <maxX> <maxY>
Note: If all four coordinates of the search envelope are specified as zero, the search envelope will be disabled.
Required/Optional
Optional
Workbench Parameter
Minimum X, Minimum Y, Maximum X, Maximum Y
SEARCH_ENVELOPE_COORDINATE_SYSTEM
This directive specifies the coordinate system of the search envelope if it is different than the coordinate system of the data.
The COORDINATE_SYSTEM directive, which specifies the coordinate system associated with the data to be read, must always be set if the SEARCH_ENVELOPE_COORDINATE_SYSTEM directive is set.
If this directive is set, the minimum and maximum points of the search envelope are reprojected from the SEARCH_ENVELOPE_COORDINATE_SYSTEM to the reader COORDINATE_SYSTEM prior to applying the envelope.
Required/Optional
Optional
Mapping File Syntax
<ReaderKeyword>_SEARCH_ENVELOPE_COORDINATE_SYSTEM <coordinate system>
Workbench Parameter
Search Envelope Coordinate System
CLIP_TO_ENVELOPE
This directive specifies whether or not FME should clip features to the envelope specified in the SEARCH_ENVELOPE directive.
Values
YES | NO (default)
Mapping File Syntax
<ReaderKeyword>_CLIP_TO_ENVELOPE [yes | no]
Workbench Parameter
Clip To Envelope
EXPOSED_ATTRS
This directive allows the selection of format attributes to be explicitly added to the reader feature type.
This is similar to exposing format attributes on a reader feature type once it has been generated; however, it is even more powerful because it enables schema-driven applications other than Workbench to access and leverage these attributes as if they were explicitly on the schema as user attributes.
The result of picking a list of attributes is a comma-separated list of attribute names and types that will be added to the schema features. Currently all reader feature types will receive the same set of additional schema attributes for a given instance of the reader.
Required/Optional
Optional
Mapping File Syntax
Not applicable.
While it is possible for FME Objects applications to invoke this directive, the required format is not documented.
This directive is intended for use in our GUI applications (for example, Workbench) only.
Workbench Parameter
Additional Attributes to Expose