Danish DSFL Reader Parameters

DSFL data files may contain spline features, which are intended to be displayed as smooth curves. Since most GIS formats do not support splines, the FME will turn the spline into a normal line, and approximate the spline curve by interpolating additional points between each value. Larger values create smoother curves, and larger resulting output files.

Determines whether or not the origin data is output as a separate features.

By default, this parameter is not selected, so the origin data is merged with other data features.

If this parameter is selected, origin data is output as dsfl_origin feature type, with each feature having its unique index number in dsfl_record_index_number attribute.

Use this parameter to expose Format Attributes in FME Workbench when you create a workspace:

• In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
• In a non-dynamic scenario, this parameter allows you to expose additional attributes on multiple feature types. Click the browse button to view the available format attributes (which are different for each format) for the reader.

Coordinate systems may be extracted from input feature data sources, may come predefined with FME, or may be user-defined. FME allows different output and input coordinate systems, and performs the required coordinate conversions when necessary.

For systems that know their coordinate system, the Coordinate System field will display Read from Source and FME will read the coordinate system from the source dataset. For most other input sources, the field will display Unknown (which simply means that FME will use default values). In most cases, the default value is all you'll need to perform the translation.

You can always choose to override the defaults and choose a new coordinate system. Select More Coordinate Systems from the drop-down menu to open the Coordinate System Gallery.

Changing a Reprojection

To perform a reprojection, FME typically uses the CS-MAP reprojection engine, which includes definitions for thousands of coordinate systems, with a large variety of projections, datums, ellipsoids, and units. However, GIS applications have slightly different algorithms for reprojecting data between different coordinate systems. To ensure that the data FME writes matches exactly to your existing data, you can use the reprojection engine from a different application.

To change the reprojection engine, Select Workspace Parameters > Spatial > Reprojection Engine. In the example shown, you can select Esri (but the selection here depends on your installed applications):

A search envelope (also known as a bounding box) is a rectangular area that defines a geographic area. In FME, the easiest way to define a search envelope is to use search envelope parameters.

Defining a search envelope is the most efficient method of selecting an area of interest because FME will read only the data that is necessary – it does not have to read an entire dataset. Search Envelope parameters apply to both vector and raster datasets and can be particularly efficient if the source format has a spatial index.

Most FME readers have parameters to define the search envelope of data that is being read:

The parameters include the x and y coordinates of the bounding box as well as a parameter that defines the coordinate system.

How to Define the Bounding Box

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 intersect with the bounding box are returned. Note that the bounding box intersection is not a full geometry intersection (based on spatial relationships) that would be returned by a transformer like the SpatialFilter.

Specifies whether or not to preserve the null value placeholder for z coordinates defined by the %H9 header tag. If Yes, the z coordinate of the geometry will be unchanged; if No, it will be set to 0.

For example, if the %H9 tag is set to -99.00 and, while reading a feature, it encounters a z coordinate of -99.00, then based on the value of this parameter, either the z coordinate will remain as -99.00 (if Yes) or changed to 0.0 (if No).

After the reader has converted splines to straight lines, use this parameter to remove extraneous points. Real values from 0 and higher are acceptable. If a negative number is input, the DSFL reader will ignore it, and not generalize the line. This parameter is valid only if Points Per Segment is at least 1.

This parameter functions similar to a Generalizer transformer using the Douglas algorithm.

A recommended use is to set Points Per Segment to a moderately high number, such as 100, and then generalize to an acceptable precision. This will keep the overall number of points generated down, but will ensure precision is available where it is needed to keep the error down.

If Yes, this directive tells the reader to also use the comma (,) as a delimiter when separating DSFL tokens as well as when parsing attributes. This setting removes commas from attributes (for example, “Vancouver, Canada” becomes “Vancouver Canada”). If No, the reader keeps the commas in the attributes.