Projection Definition and Coordinate Transformation

Liz Sanderson
Liz Sanderson
  • Updated

FME Version

  • FME 2022.0

Introduction

In this tutorial, you will learn how to define a coordinate system in FME Workbench and how to reproject data to another coordinate system using the Reprojector Transformer.

 

Step-by-step Instructions 

Exercise 1: Defining Projections When Adding a Reader

In this scenario, you want to define the projection of your dataset to match the coordinate system information that is stated in a metadata file. The polygon boundary you will use was inadvertently projected to the wrong coordinate system (UTM83-11), so you want to define the correct projection (UTM83-10) before performing your analysis.

Source
The source dataset is a feature class in an Esri Geodatabase containing a land boundary, but the dataset is in an incorrect coordinate system. 
Input1.png

1. Create a New Workspace
Open FME Workbench and create a blank workspace. 
NewWorkspace.png
 
2. Add an Esri Geodatabase (File Geodb Open API) Reader
Add an Esri Geodatabase (File Geodb Open API) reader to the canvas by clicking on the Reader button on the top menu bar or by going to Readers > Add Reader. In the Add Reader dialog, select Esri Geodatabase (File Geodb Open API) as the Format, then for Dataset, browse to the LandBoundary.gdb dataset, which is available for download from the Files section on this article. 
Reader1.png
 
The easiest way to define a coordinate system in FME is when adding the reader. To define a coordinate system, you can either select a coordinate system from the drop-down list or type in the name of the coordinate system (i.e. “UTM83-10”) - the list will filter coordinate systems as you type and will only return coordinate systems that contain what is being typed in.
Reader2.png
 
Select the UTM83-10 from the list of Coordinate Systems or type in “UTM83-10” to define the coordinate system. Then click OK. 
Alternatively, you can set the reader/writer’s Coordinate System in the Navigator window. See the Working with Coordinate Systems in FME article for more information.
 
3. Run Workspace
Connect an Inspector transformer to LandBoundary reader feature type. 
 
Run the workspace by clicking on the Run button on the top toolbar, or by using Run > Run Workspace on the top menu bar. 
Run.png
 
After running the workspace, the data will be displayed in Visual Preview. Click on a feature, then open the Feature Information window to view the coordinate system. Optionally, add a background map to ensure the data is where it is supposed to be. 
Output1.png
 

Exercise 2: Reprojecting Data

In Exercise 2, you will reproject data because it is currently using the LL83 Coordinate system (measured in degrees), and you need it to be in a coordinate system that uses linear units. In this scenario, you will reproject data from lat/long LL83 (degrees) to UTM83-10 (meters).

Source
The source dataset is a feature class in an Esri Geodatabase containing contour lines in the LL83 coordinate system. 

Input2.png
 
1. Create a New Workspace
Open FME Workbench and create a blank workspace. 
NewWorkspace.png
 
2. Add an Esri Geodatabase (File Geodb Open API) Reader
Add an Esri Geodatabase (File Geodb Open API) reader to the canvas by clicking on the Reader button on the top menu bar or by going to Readers > Add Reader. In the Add Reader dialog, select Esri Geodatabase (File Geodb Open API) as the Format, then for Dataset, browse to the Contours.gdb dataset, which is available for download from the Files section on this article. 
Reader3.png

Note: If continuing in the same instance of FME as Exercise 1, you may need to remove the Coord. System and open the parameters to select a different feature class. 
 
3. View Coordinate System
After adding the reader, click on the Contours reader feature type to open the popup menu, then click on View Source Data. 
ViewSource.png
 
In Visual Preview, click on a feature, then open the Feature Information window to view the coordinate system. Note that the current coordinate system is LL83. 
Input2.png
 
4. Reproject Data
With the Contours reader feature type still selected,  add a Reprojector transformer to the canvas by typing “Reprojector” to bring up the list of FME Transformers in the Quick Add Search. Select the Reprojector from the list of Transformers by double-clicking or by using the arrow keys and the Enter key to add it. 
 Quickadd.png
Connection.png

Double-click on the Reprojector to open the parameters. In the parameters, set the Destination Coordinate System to UTM83-10, then click OK. 
Reprojector.png
 
5. Run Workspace
Connect an Inspector transformer to Reprojector reprojected output port. 
Workspace.png

Run the workspace by clicking on the Run button on the top toolbar, or by using Run > Run Workspace on the top menu bar. 
Run.png
 
After running the workspace, the data will be displayed in Visual Preview. Click on a feature, then open the Feature Information window to view the coordinate system. The coordinate system should now be UTM83-10. 
Output2.png
 

 

Data Attribution

Data used in this tutorial originates from open data made available by the City of Vancouver, British Columbia. It contains information licensed under the Open Government License - Vancouver.

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