AttributeReprojector

In this example, we start with a CSV file of drinking fountain locations. A CSV dataset has no geometry, but it does contain coordinates for the fountains, in a UTM projection.

The CSV features are routed into an AttributeReprojector.

In the parameters dialog, the x and y attributes containing the coordinates are specified accordingly, the source coordinate system entered (as UTM83-10), and the new destination coordinate system chosen (LL-WGS84).

The new coordinates are calculated and replace the existing attribute values. The transformer does not create geometry, it only supplies values.

In this example, we start with a CSV file of drinking fountain locations, which has no geometry. It contains coordinates for the fountains, in a UTM projection. We want to add an additional coordinate system’s coordinates to it, to provide options for users who may not have access to software that will reproject it for them.

The CSV features are routed into an AttributeManager, and then to the AttributeReprojector.

In the AttributeManager, we add two new attributes, named x_LLWGS84 and y_LLWGS84. Using the Attribute Value column, we copy the current x and y coordinates (still in UTM) from the x_coord and y_coord attributes.

In the AttributeReprojector parameters dialog, the x and y attributes are set to the new (copied) attributes, and the Source and Destination coordinate systems chosen.

The output now contains both sets of coordinates - the original UTM and new LL-WGS84.

Coordinate systems generally have a name and a definition, and the syntax of that definition can vary greatly between both spatial data formats and other coordinate system libraries. Custom and local coordinate systems can also be defined in FME, further complicating matters. For in-depth information, see the Working With Coordinate Systems documentation.

Reprojections are generally done with the FME Reprojection Engine, which is based on the CS-Map coordinate system library. This default can be overridden on a per-workspace basis, using the Workspace Parameters > Translation > Reprojection Engine parameter, and set to Esri. Where appropriate, FME will use the Esri Reprojection Engine if it is selected there, with or without an Esri product being installed.

Coordinate System Support

These transformers perform various coordinate system-related tasks, but do not reproject the data.

Coordinate System Reprojection

Different coordinate system libraries (engines) not only contain coordinate system definitions, they also have unique reprojection algorithms. FME’s generic reprojection transformers, in the first table below, default to using the FME (CS-Map) library.

A selection of other libraries is also available, some of which are specific to certain areas of the world or software platforms.

Inherent reprojections, as in a workspace with different input and output coordinate systems selected, default to using the FME (CS-Map) library.

If you are reprojecting explicitly with a transformer in the workspace, using library-specific transformers is recommended. In the case of CsmapReprojector versus the Reprojector (with default engine), the library may be identical, but the CSMapReprojector handles vertical coordinate calculations whereas the Reprojector does not.

Generic Reprojection Transformers

Library-Specific Reprojection Transformers (Recommended)

The features that contain the attributes you want to reproject.

Features with reprojected attributes as specified.

Defining Values

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.

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.

Text Editor

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.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

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.

Content Types

String Functions	These functions manipulate and format strings.
Special Characters	A set of control characters is available in the Text Editor.
Math Functions	Math functions are available in both editors.
Date/Time Functions	Date and time functions are available in the Text Editor.
Math Operators	These operators are available in the Arithmetic Editor.
FME Feature Functions	These return primarily feature-specific values.
FME Parameters	FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters	Create your own editable parameters.

Table Tools

Transformers with table-style parameters have additional tools for populating and manipulating values.

Note: Not all tools are available in all transformers.