Data Distribution Tutorial

Introduction

Welcome to the Data Distribution Tutorial! This workspace allows users to extract and transform spatial data based on a defined area. It begins by capturing the user-defined area in GeoJSON format and reprojecting it to match the feature coordinate system. Next, it reads the selected feature layers that intersect with the defined area and clips these layers to the specified boundary. Finally, the workspace writes the clipped layers to the desired format and coordinate system using a generic writer.

Requirements

Before starting this guide, we highly recommend that you have completed at least one of the Getting Started with FME Form articles and familiarize yourself with published parameters. 

Step-By-Step Instructions

From the Files section of this article, download the Transit.gdb file.

1. Open FME Workbench 

Open FME Workbench and click on Blank Workspace on the Get Started page. 

Alternatively, you can also click on File > New.

2. Create User Parameters

In this tutorial, you will create four user parameters. These parameters are designed to guide users and gather their input on their desired output.

The first parameter will prompt users to specify which layers they want to download from the database.

• Type: Choice
• Parameter Identifier: FEATURETYPE
• Prompt: Layers to Download
• Parameter: Published, Required
• Choice configuration: List 
  • Choices: BusRoutes, BusStops, SkytrainStations, SkytrainLines
• Allow Multiple Selection: Enabled
• Default Value: <Leave Blank>

The second parameter will allow users to select the area from which they want to download data. By creating a geometry user parameter type, users can display the specified coordinates on a map and define the desired geometry. Since the Transit database is in Vancouver, the initial bounds are set to that location. If you are unsure of your specific initial bounds, refer to the How to Determine Map Bounds with FME section. 

• Type: Geometry
• Parameter Identifier: GEOM
• Prompt: Area of Interest
• Parameters: Published, Required, Disable Attribute Assignment
• Geometry Configuration:
  • Geometry Encoding: GEOJSON
  • Geometry Types: Polygon Box
  • Specify initial bounds for map displays: Enabled
  • Top: 49.2548
  • Left: -123.244
  • Bottom: 49.3034
  • Right:-123.071
• Default Value: <Leave Blank>

The third parameter allows users to select an output format for their data.

• Type: Choice
• Parameter Identifier: GENERIC_FORMAT
• Prompt: Output Format
• Parameter: Published, Required
• Choice configuration: Dropdown
  • Choices: ACAD, GML, OGCKML, PDF2D, SHAPEFILE, CSV - You can use Import from Reader to quickly search for them as well. 
  • Allow Choice Edit: No
• Default Value: <Leave Blank>

The fourth parameter enables users to select the output coordinate system. Given that the Transit database covers the Vancouver region, we will restrict the coordinate system choices to those suitable for this area.

• Type: Choice
• Parameter Identifier: COORDSYS
• Prompt: Output Coordinate System
• Parameter: Published, Required
• Choice Configuration: Dropdown
  • Choices: BCALB-83, BCPOLY-83, EPSG:26910, EPSG: 4326 - You can use Import from Coordinate Systems to quickly search for them as well
  • Allow Choice Edit: No
• Conditional Visibility: 
  • If Generic_Format Is Comma Separated Value (CSV)
  • Then Hide
  • Else Show As Enabled
• Default Value: <Leave Blank>

Conditional Visibility of workspace published parameters enables authors to determine under what condition(s) published parameters will be visible at runtime. This functionality allows authors to disable or hide published parameters that are not relevant to a particular translation based on the value selected for another user parameter. We want to set it up here so that when users choose a CSV format file, the Coordinate System parameter will be hidden, making the dialog less cluttered. You can read Working With Conditionally Visible Published User Parameters in FME Form for more information.

An important point to keep in mind about the new Conditional Visibility property is that the order of parameters in the Manage User Parameters dialog matters. More specifically, when one parameter’s visibility depends on the state or value of another parameter, the dependent parameter must reside below its related parameter in the Manage User Parameters dialog. Otherwise, the visibility condition set on the dependent parameter will no longer be valid, and its If…clause will appear red.

3. Add Creator and GeometryReplacer Transformers

Add a Creator transformer to your workspace using the default properties. The Creator transformer generates an initial feature, which acts as a starting point for the workspace. Then, add a GeometryReplacer and connect the Creator transformer to it. The GeometryReplacer transformer takes the user-defined area and replaces the initial feature's geometry with this user-defined geometry.

4. Modify GeometryReplacer parameters

Open the GeometryReplacer parameters. Set the Geometry Encoding to GeoJSON, and then set the Geometry Source to the GEOM user parameter.

5. Add the Reprojector transformer and modify the parameters

Since the Transit.gdb is in Vancouver, we need to ensure that the data is set in UTM83 Zone 10. To achieve this, add a Reprojector transformer to the canvas and connect it to the GeometryReplacer transformer.

In the Reprojector parameters, set the Source Coordinate System to LL84. We defined the initial bounds box in previous steps, and since the GeometryReplacer is connected to the Reprojector transformer, we know the coordinate system. Set the Destination Coordinate System to UTM83-10.

6. Add a Feature Reader transformer and modify the parameters

Add a FeatureReader transformer to read from the transit.gdb file.

In the parameters, set the format to Esri Geodatabase (File Geodb Open API) and select the transit.gdb file that you downloaded.

In the Constraints section, link the FEATURETYPE user parameter to the Feature Types to Read property. This ensures that the workspace only reads the features selected by users rather than all of them. For the Spatial Filter, set it as Initiator OGC-Intersects Result.

Finally, expand the Output Ports section, choose Specified, and add the four features by clicking the ellipsis. This assigns each feature its own output port.

7. Add Clipper transformer

Add a Clipper transformer to clip the feature layers to the region specified by users. Connect the <Initiator> port to the Clipper port, and connect the BusRoutes, BusStops, SkytrainLines, and SkytrainStations ports to the Candidate port.  

In the Clipper parameters, set "No" for Multiple Clippers and leave the rest as default.

8. Add Test Filters

One of the objectives of this workspace is to allow users to select their preferred data format for the final output. Among these formats is OGCKML, for which we want to customize the appearance of the output file. To achieve this, add a Test Filter transformer and create two output ports: one for KML data format and the other for all remaining formats. The KML output will undergo styling adjustments before the final output, while the other formats will be directly routed to a generic writer.

In the TestFilter parameters, set the Port Definitions as the following:

9. Add styling for KML Output

We want to add styling for KML output to create an informative representation of the data and ensure the final result has the usability requirements for users interacting with KML format data.

Add FeatureTypeFilter Transformer 

First, add a FeatureTypeFilter transformer to route features to different output ports, allowing for separate customization of each type. In the parameters, make sure to include all four main feature types:

• SkytrainStations
• BusStops
• SkytrainLines
• BusRoutes

Add KMLStyler Transformer 

Next, add a KMLStyler transformer for each of the four feature types. 

• SkytrainStations: These are point features; adding icons is ideal. In the KMLStyler Parameters, expand the Icon section and choose red or a color of your choice. Leave the other settings as default.

• BusStops feature type: Follow the same steps as for SkytrainStations, but select orange or any other color to differentiate them.

• SkytrainLines feature type: These are line features, so icons are unnecessary. Change the color in the Color section to orange or another color of your choice. Expand Line Style and set the Line Width to 2 for better visibility in Google Earth.

• BusRoutes feature type: Repeat the steps for SkytrainLines, but choose green or any other color as the color.

Add KMLPropertySetter Transformer 

Add a KML Property Setter transformer and connect it to each of the four KML Styler transformers created in the previous steps. The KML Property Setter transformer ensures that the names of each feature type will appear in the output. For example, for the BusStops output, the stop number will be visible when added to Google Earth.

In the KMLPropertySetter parameters, modify only the attribute value for Name in the navigation tree. You can leave the other settings as default.

• SkytrainStations: StationName
• BusStops: StopNumber
• SkytrainLines: LineName
• BusRoutes: RouteName

Here’s an example of the KMLPropertySetter transformer for SkytrainStations

Add Attribute Exposer transformer

To access the unexposed fme_feature_type and fme_basename attributes, add an AttributeExposer transformer. In the parameters, select fme_feature_type and fme_basename as the attributes to expose. Ensure all four feature types are connected to this transformer. Your workspace should now look like this.

10. Add a Generic Writer

Add a Generic writer to the canvas using the default setting. 

When the Feature Type window pops up, change the Feature Type Name to fme_feature_type attribute value. This method is called Feature Type Fanout, which is a way to split output data based upon the value of an attribute. To learn more about Feature Type Fanout, see the Fanout | How to Separate Features Based on an Attribute article. 

Connect the Other Formats output port from the TestFilter transformer and the AttributeExposer to the Generic writer feature type. Your final workspace should look similar to this.

Feel free to add your own bookmarks and annotations to help you understand the steps better. You can refer to the Organizing Workspaces documentation to efficiently arrange your workspace.

11. Link to a Parameter

In the Navigator window, ensure the Coordinate System is linked to the user parameter COORDSYS. This will provide users with access to the curated list of coordinate systems selected in the previous steps. This is done by right-clicking on the parameter and selecting Link to Parameter. 

12. Test Workspace

Run the Workspace with Prompt to test your workspace's functionality. Click on the drop-down arrow next to the Run button and enable Prompt for Parameters. 

Then click the Run Workspace button. You will be prompted to enter values for the parameters. You can use the below coordinates to test out the workspace:

 {"type":"Polygon","coordinates":[[[-123.134079,49.276543],[-123.134079,49.287126],[-123.112278,49.287126],[-123.112278,49.276543],[-123.134079,49.276543]]]}. 

Once ready, click Run.

If you select all four feature types, a total of 42 features should be output. If you choose KML as the output format, the workspace will process through the KMLStyling transformers. For formats other than KML, the output will be written directly after the Test Filter output.

                                             KML Format Output

                                              Other Format Output

Once the workspace finished running, check the Translation Log for any errors and check the destination folder to make sure you have the data translated correctly.

Congratulations, you have completed building a workspace for data distribution! If you want to publish the workspace to FME Flow, refer to the article Publish a Workspace to FME Flow and Run It. For a step-by-step guide on creating a workspace app using this data distribution workspace, follow the instructions in the FME Flow App Examples article.

Explore our FME Support Center for more tutorials, tips, and guidelines. Additionally, visit FME Academy to explore our comprehensive training catalog for a more in-depth study!

Data Attribution

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