PROJAttributeReprojector

Reprojects coordinates stored as attributes from one coordinate system to another using the PROJ library.

Typical Uses

Reprojecting features when explicitly using the PROJ library is desired
Adding additional coordinate pairs as attributes, in alternate coordinate systems

How does it work?

The PROJAttributeReprojector accepts any feature. The user specifies the attributes containing x, y, and optionally z coordinates, and configures either an Automatic or Manual Transformation.

The transformer reprojects the coordinates according to these selections, using the PROJ reprojection library, and updates the x, y, and z attributes to the new values, overwriting the originals.

This transformer does not alter the feature’s geometry – only the values of the selected X and Y Attributes (if they contain coordinate values) are changed. Accurate results depend on the user’s correct specification of the source coordinate system.

FME currently uses PROJ version 7.x.

For Automatic transformations, the Source Coordinate System and Destination Coordinate System must be specified explicitly.

For Manual transformations, a PROJ string must be provided describing the desired transformation, as documented at PROJ’s Transformation Pipelines and shown in the examples further below. WKT2 descriptions are also valid.

Coordinate System Definitions

This transformer will accept coordinate systems defined in any one of the following forms.

Definition Style	Example: LL-WGS84 Defined	External Reference
EPSG Number	EPSG:4326	EPSG Website
Well-Known Text (WKT1 or WKT2)	GEODCRS["WGS 84", DATUM["World Geodetic System 1984", ELLIPSOID["WGS 84",6378137,298.257223563, LENGTHUNIT["metre",1.0]]], CS[ellipsoidal,2], AXIS["latitude",north,ORDER[1]], AXIS["longitude",east,ORDER[2]], ANGLEUNIT["degree",0.01745329252], ID["EPSG",4326]]	Open Geospatial Consortium: Geographic information — Well-known text representation of coordinate reference systems Note that the EPSG website can also provide WKT strings for specific coordinate systems.
PROJ String	+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs	PROJ Projections

Definition Style

Example: LL-WGS84 Defined

External Reference

EPSG Number

EPSG:4326

EPSG Website

Well-Known Text (WKT1 or WKT2)

GEODCRS["WGS 84",

DATUM["World Geodetic System 1984",

ELLIPSOID["WGS 84",6378137,298.257223563,

LENGTHUNIT["metre",1.0]]],

CS[ellipsoidal,2],

AXIS["latitude",north,ORDER[1]],

AXIS["longitude",east,ORDER[2]],

ANGLEUNIT["degree",0.01745329252],

ID["EPSG",4326]]

Open Geospatial Consortium: Geographic information — Well-known text representation of coordinate reference systems

Note that the EPSG website can also provide WKT strings for specific coordinate systems.

PROJ String

+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs

PROJ Projections

They are fully interchangeable and can be used in any combination to define the Source and Destination Coordinate System for an Automatic transformation.

They may also be used in a PROJ string or pipeline for a Manual transformation.

Note that EPSG and WKT representations can more fully describe a coordinate system than PROJ strings, and so are the preferred definition types.

Geographic Transformations and Grids

Geographic Transformations control how coordinates are converted between different datums.

For an Automatic Transformation, FME will attempt to select an appropriate transformation between the Source and Destination coordinate systems.

Manual Transformations are performed as specified in the Manual Transformation Parameters.

Grid-Based Datum Adjustments

Some areas use grid shift files for datum conversion. Many grids needed by PROJ are already included with FME, however additional grids may be downloaded from the PROJ website. Download the proj-data archive and extract it to your [FME User Directory]/ProjData folder.

FME can also access many PROJ grids online at cdn.proj.org. Online access may be enabled in FME Desktop, Tools > FME Options > Coordinate Systems.

PROJ User Data

Grids and customized proj.db files may be placed in your [FME User Directory]/ProjData folder.

Sample ProjData folder locations:

macOS	/Users/[User]/Library/Application\ Support/FME/ProjData/
Windows 10	C:\Users\[User]\Documents\FME\ProjData
Linux	/home/[User]/.fme/ProjData

PROJ transformers will give preference to files placed in this folder over other locations, including the proj.db and grid files shipped with FME.

Examples

Example: WKT2 Transformation Description

The previous example could also be performed using Well-Known Text (WKT2) to describe the transformation.

WKT2 Transformation Description

Copy

CONCATENATEDOPERATION["Inverse of UTM zone 10N + NAD27 to NAD83 (4) + UTM zone 10N",
    SOURCECRS[
        PROJCRS["NAD27 / UTM zone 10N",
            BASEGEOGCRS["NAD27",
                DATUM["North American Datum 1927",
                    ELLIPSOID["Clarke 1866",6378206.4,294.978698213898,
                        LENGTHUNIT["metre",1]]],
                PRIMEM["Greenwich",0,
                    ANGLEUNIT["degree",0.0174532925199433]],
                ID["EPSG",4267]],
            CONVERSION["UTM zone 10N",
                METHOD["Transverse Mercator",
                    ID["EPSG",9807]],
                PARAMETER["Latitude of natural origin",0,
                    ANGLEUNIT["degree",0.0174532925199433],
                    ID["EPSG",8801]],
                PARAMETER["Longitude of natural origin",-123,
                    ANGLEUNIT["degree",0.0174532925199433],
                    ID["EPSG",8802]],
                PARAMETER["Scale factor at natural origin",0.9996,
                    SCALEUNIT["unity",1],
                    ID["EPSG",8805]],
                PARAMETER["False easting",500000,
                    LENGTHUNIT["metre",1],
                    ID["EPSG",8806]],
                PARAMETER["False northing",0,
                    LENGTHUNIT["metre",1],
                    ID["EPSG",8807]]],
            CS[Cartesian,2],
                AXIS["(E)",east,
                    ORDER[1],
                    LENGTHUNIT["metre",1]],
                AXIS["(N)",north,
                    ORDER[2],
                    LENGTHUNIT["metre",1]],
            ID["EPSG",26710]]],
    TARGETCRS[
        PROJCRS["NAD83 / UTM zone 10N",
            BASEGEOGCRS["NAD83",
                DATUM["North American Datum 1983",
                    ELLIPSOID["GRS 1980",6378137,298.257222101,
                        LENGTHUNIT["metre",1]]],
                PRIMEM["Greenwich",0,
                    ANGLEUNIT["degree",0.0174532925199433]],
                ID["EPSG",4269]],
            CONVERSION["UTM zone 10N",
                METHOD["Transverse Mercator",
                    ID["EPSG",9807]],
                PARAMETER["Latitude of natural origin",0,
                    ANGLEUNIT["degree",0.0174532925199433],
                    ID["EPSG",8801]],
                PARAMETER["Longitude of natural origin",-123,
                    ANGLEUNIT["degree",0.0174532925199433],
                    ID["EPSG",8802]],
                PARAMETER["Scale factor at natural origin",0.9996,
                    SCALEUNIT["unity",1],
                    ID["EPSG",8805]],
                PARAMETER["False easting",500000,
                    LENGTHUNIT["metre",1],
                    ID["EPSG",8806]],
                PARAMETER["False northing",0,
                    LENGTHUNIT["metre",1],
                    ID["EPSG",8807]]],
            CS[Cartesian,2],
                AXIS["(E)",east,
                    ORDER[1],
                    LENGTHUNIT["metre",1]],
                AXIS["(N)",north,
                    ORDER[2],
                    LENGTHUNIT["metre",1]],
            ID["EPSG",26910]]],
    STEP[
        CONVERSION["Inverse of UTM zone 10N",
            METHOD["Inverse of Transverse Mercator",
                ID["INVERSE(EPSG)",9807]],
            PARAMETER["Latitude of natural origin",0,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8801]],
            PARAMETER["Longitude of natural origin",-123,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8802]],
            PARAMETER["Scale factor at natural origin",0.9996,
                SCALEUNIT["unity",1],
                ID["EPSG",8805]],
            PARAMETER["False easting",500000,
                LENGTHUNIT["metre",1],
                ID["EPSG",8806]],
            PARAMETER["False northing",0,
                LENGTHUNIT["metre",1],
                ID["EPSG",8807]],
            ID["INVERSE(EPSG)",16010]]],
    STEP[
        COORDINATEOPERATION["NAD27 to NAD83 (4)",
            SOURCECRS[
                GEOGCRS["NAD27",
                    DATUM["North American Datum 1927",
                        ELLIPSOID["Clarke 1866",6378206.4,294.978698213898,
                            LENGTHUNIT["metre",1]]],
                    PRIMEM["Greenwich",0,
                        ANGLEUNIT["degree",0.0174532925199433]],
                    CS[ellipsoidal,2],
                        AXIS["geodetic latitude (Lat)",north,
                            ORDER[1],
                            ANGLEUNIT["degree",0.0174532925199433]],
                        AXIS["geodetic longitude (Lon)",east,
                            ORDER[2],
                            ANGLEUNIT["degree",0.0174532925199433]],
                    ID["EPSG",4267]]],
            TARGETCRS[
                GEOGCRS["NAD83",
                    DATUM["North American Datum 1983",
                        ELLIPSOID["GRS 1980",6378137,298.257222101,
                            LENGTHUNIT["metre",1]]],
                    PRIMEM["Greenwich",0,
                        ANGLEUNIT["degree",0.0174532925199433]],
                    CS[ellipsoidal,2],
                        AXIS["geodetic latitude (Lat)",north,
                            ORDER[1],
                            ANGLEUNIT["degree",0.0174532925199433]],
                        AXIS["geodetic longitude (Lon)",east,
                            ORDER[2],
                            ANGLEUNIT["degree",0.0174532925199433]],
                    ID["EPSG",4269]]],
            METHOD["HORIZONTAL_SHIFT_GTIFF"],
            PARAMETERFILE["Latitude and longitude difference file","ca_nrc_ntv2_0.tif"],
            OPERATIONACCURACY[1.5],
            ID["DERIVED_FROM(EPSG)",1313]]],
    STEP[
        CONVERSION["UTM zone 10N",
            METHOD["Transverse Mercator",
                ID["EPSG",9807]],
            PARAMETER["Latitude of natural origin",0,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8801]],
            PARAMETER["Longitude of natural origin",-123,
                ANGLEUNIT["degree",0.0174532925199433],
                ID["EPSG",8802]],
            PARAMETER["Scale factor at natural origin",0.9996,
                SCALEUNIT["unity",1],
                ID["EPSG",8805]],
            PARAMETER["False easting",500000,
                LENGTHUNIT["metre",1],
                ID["EPSG",8806]],
            PARAMETER["False northing",0,
                LENGTHUNIT["metre",1],
                ID["EPSG",8807]],
            ID["EPSG",16010]]],
    USAGE[
        SCOPE["unknown"],
        AREA["Canada - onshore - Alberta; British Columbia; Manitoba; New Brunswick; Newfoundland and Labrador; Northwest Territories; Nova Scotia; Nunavut; Ontario; Prince Edward Island; Quebec; Saskatchewan; Yukon; offshore east coast."],
        BBOX[40.04,-141.01,83.17,-47.74]]]

Usage Notes

This transformer does not change the feature's coordinates – it only changes the values of the selected X, Y, and Z attributes (if they contain coordinate values).
Earlier versions of PROJ used the proj-datumgrid grid files package, which is still available on the PROJ website. It should be replaced by the current proj-data package.
FME has a Workspace Parameter, Reprojection Engine, that may be set to either FME (CS-Map) or Esri. This transformer will override this parameter setting.
The AttributeReprojector provides similar functionality, and will use the default library (CS-Map or Esri) set in FME. It does not handle z values.
To reproject coordinates stored as geometry, consider using the PROJReprojector.
Automatic Transformations will produce a PROJ pipeline string in the log, which can be used as a template for Manual Transformations.

Working With Coordinate System Transformers

FME inherently supports coordinate system transformations and reprojections.

Coordinate System Support and Reprojection

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.

CoordinateSystemDescriptionConverter	Looks up coordinate system names and definitions between FME’s internal format and common third-party and open source representations, storing the results as an attribute.
CoordinateSystemExtractor	Retrieves the name of the feature's assigned FME coordinate system into an attribute.
CoordinateSystemRemover	Removes the coordinate system from features, without modifying geometry or coordinates.
CoordinateSystemSetter	Assigns a specified coordinate system to features, without modifying geometry or coordinates.
LocalCoordinateSystemSetter	Assigns a specified local coordinate system to features, without modifying geometry or coordinates.

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
AttributeReprojector	Reprojects x and y coordinates stored as attributes from one coordinate system to another.	FME (default) or Esri
CommonLocalReprojector	Reprojects one or more features to a local coordinate system centered on the bounding box containing all features.	FME (default) or Esri
ReprojectAngleCalculator	Converts a given angle from one coordinate system to another.	FME (default) or Esri
ReprojectLengthCalculator	Converts a given length from one coordinate system to another.	FME (default) or Esri
Reprojector	Reprojects feature x and y coordinates from one coordinate system to another.	FME (default) or Esri

Library-Specific Reprojection Transformers (Recommended)

		Library (External Links)
CsmapAttributeReprojector	Reprojects x, y, and optionally z coordinates stored as attributes from one coordinate system to another using the CS-MAP library.	CS-Map
CsmapReprojector	Reprojects feature x, y, and optionally z coordinates from one coordinate system to another using the CS-Map library.	CS-Map
EsriReprojector	Reprojects feature coordinates from one coordinate system to another using the Esri reprojection library.	Esri
GridInQuestIIReprojector Great Britain Northern Ireland Republic of Ireland	Reprojects feature coordinates from one coordinate system to another using the Grid InQuestII engine from Ordnance Survey, for use in Great Britain, Ireland, and Northern Ireland.	Grid InQuestII
GtransAttributeReprojector Sweden	Reprojects coordinates stored as attributes from one coordinate system to another using the Gtrans reprojection engine from the National Land Survey of Sweden (Lantmäteriet).	Gtrans
GtransReprojector Sweden	Reprojects feature coordinates from one coordinate system to another using the Gtrans reprojection engine from the National Land Survey of Sweden (Lantmäteriet).	Gtrans
PROJAttributeReprojector	Reprojects coordinates stored as attributes from one coordinate system to another using the PROJ library.	PROJ
PROJReprojector	Reprojects feature coordinates from one coordinate system to another using the PROJ library.	PROJ
ReframeReprojector Switzerland	Reprojects feature coordinates from one coordinate system to another in Switzerland, using the Reframe library from the Federal Office of Topography (swisstopo).	REFRAME

Configuration

Input Ports

Output Ports

Parameters

Transformation Type

Type

Select a method for applying a transformation.

Automatic Transformation

Source and Destination Coordinate System are specified, and a transformation is chosen automatically by PROJ.

For information on how PROJ performs automatic transformations, see Computation of coordinate operations between two CRS at PROJ.

Note that Automatic Transformations may change between FME releases.

Manual Transformation

A PROJ or WKT2 string will be entered specifying the Source and Destination Coordinate Systems and any other required transformation steps such as grid shift files.

Automatic Transformation Parameters

Source Coordinate System

If Transformation Type is Automatic Transformation, specify the coordinate system of the incoming features.

The default is <Read from feature>, which reads the features’ existing coordinate system(s).

Coordinate systems may also be explicitly selected from the Coordinate System Gallery, entered directly, or provided via an attribute value or user parameter.

Acceptable forms include EPSG number, WKT2 string, or PROJ string (excluding pipelines).

Destination Coordinate System

If Transformation Type is Automatic Transformation, specify the coordinate system to be reprojected to.

Coordinate systems may be explicitly selected from the Coordinate System Gallery, entered directly, or provided via an attribute value or user parameter.

Acceptable forms include EPSG number, WKT2 string, or PROJ string (excluding pipelines).

Note that FME will attempt to determine what the destination coordinate system’s corresponding FME coordinate system is, and tag the output features with it, unless an override is specified by Output Coordinate System Tag.

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.

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. 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.

How to Set Parameter Values

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.

Dialog Options - Tables

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

Table Tools

Row Reordering

Enabled once you have clicked on a row item. Choices include:

Add a row
Remove a row
Move current row up one
Move current row down one
Move current row to top
Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

Cut a row - delete and copy to clipboard
Copy a row to the clipboard
Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

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

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

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.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
Dependencies	None
Aliases
History

FME Community

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Search for all results about the PROJAttributeReprojector on the FME Community.

Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.

X Attribute	Provide the attribute containing the X coordinate to be reprojected.
Y Attribute	Provide the attribute containing the Y coordinate to be reprojected.
Z Attribute	Provide the attribute containing the Z coordinate to be reprojected.