Constructs a Delaunay triangulation based on input points and breaklines. Contour lines are then generated from the triangulation.
These input features must be 3D. Other than points, lines and area geometries, they may also be raster, point cloud, and aggregate geometries. Raster features must represent a DEM (that is, they have a single band with no palette).
A minimum of 3 unique points are required to construct a surface model. Points with duplicate x and y values will be dropped.
These input features must be 3D, and may reside inside an aggregate structure.
Breakline edges will be found in the edge pool of the underlying surface model. Sometimes, a breakline edge will be split up to allow an optimal triangulation of the surface model. Points with duplicate x and y values will be dropped.
This output port produces contour lines. Each contour is 2D or 3D depending on Output Contour Dimension, and stores its elevation in the attribute specified in Output Elevation Attribute. If contours are 3D, then their z values are equivalent to their elevation attribute values.
Tip: The parameter Conflict Resolution can filter out a subset of input Points/Lines to ensure a well-constructed surface model.
Features containing point(s) with invalid z value(s) are output to this port.
Rejected features will have an fme_rejection_code attribute with one of the following values: INVALID_BREAKLINES_GEOMETRY_VERTICES, INVALID_GEOMETRY_DIMENSION, INVALID_GEOMETRY_VERTICES, INVALID_POINT_GEOMETRY_VERTICES, INVALID_POINTS_GEOMETRY_RASTER_NUM_BANDS, INVALID_POINTS_GEOMETRY_RASTER_NUM_PALETTES.
This parameter allows groups to be formed by attribute values. Zero or more attributes may be specified.
Input features with the same attribute values are placed into the same group. The transformer then operates independently on each group of input features.
If this parameter is left blank, the transformer will treat the entire set of input features as one group.
Select the point in processing at which groups are processed:
Considerations for Using Group By
There are two typical reasons for using When Group Changes (Advanced) . The first is incoming data that is intended to be processed in groups (and is already so ordered). In this case, the structure dictates Group By usage - not performance considerations.
The second possible reason is potential performance gains.
Performance gains are most likely when the data is already sorted (or read using a SQL ORDER BY statement) since less work is required of FME. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains).
Sorting becomes more difficult according to the number of data streams. Multiple streams of data could be almost impossible to sort into the correct order, since all features matching a Group By value need to arrive before any features (of any feature type or dataset) belonging to the next group. In this case, using Group By with When All Features Received may be the equivalent and simpler approach.
Note Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.
As with many scenarios, testing different approaches in your workspace with your data is the only definitive way to identify performance gains.
This parameter is used to determine which input points to add to the surface model as vertices. Specifying a value of 0 turns off vertex filtering.
Tip: A larger value will speed up surface model construction. The larger the value, the more input points will be filtered out. For input files with millions – or even billions – of points, it becomes essential to increase this value.
When a positive value for surface tolerance is specified, it works as follows. For each vertex that is being added to the model:
Output Contour Interval
This parameter specifies the elevation separation of the output contours.
Output Contour Dimension
This parameter specifies whether the output contours are 2D or 3D. 2D contours are equivalent to 3D contours, except that the z coordinates are dropped.
Tip: When the input dataset is large enough, setting this parameter to 2D will result in a visible performance improvement.
This parameter controls whether input points on the contour interval are dropped, or perturbed. Not dropping or perturbing these points would result in topologically invalid contours.
Name the attribute to contain the elevation value.
Editing Transformer Parameters
Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.
There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.
Using the Text Editor
The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.
Using the Arithmetic Editor
The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.
Set values depending on one or more test conditions that either pass or fail.
Expressions and strings can include a number of functions, characters, parameters, and more.
When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.
|These functions manipulate and format strings.
|A set of control characters is available in the Text Editor.
|Math functions are available in both editors.
|Date and time functions are available in the Text Editor.
|These operators are available in the Arithmetic Editor.
|These return primarily feature-specific values.
|FME and workspace-specific parameters may be used.
|Creating and Modifying User Parameters
|Create your own editable parameters.
Dialog Options - Tables
Transformers with table-style parameters have additional tools for populating and manipulating values.
Enabled once you have clicked on a row item. Choices include:
Cut, Copy, and Paste
Enabled once you have clicked on a row item. Choices include:
Cut, copy, and paste may be used within a transformer, or between transformers.
|Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.
|Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.
Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.
Note: Not all tools are available in all transformers.
The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.
Search for all results about the ContourGenerator on the FME Community.