Visualizing Spatial Data – Toggling map layers
March 27, 2013 Leave a comment
Last time I showed you how to add a PushPin to your map control. But what if you want to toggle that (or any other) layer in your map control?
The reason I wanted to do this, is that I want to allow the users of my report to toggle different layers in the map control. That way, you can pre-build all the different layers you think your users need into a single report, and just let them toggle the layers themselves. That saves you a lot of time building a report for every single combination of layer-types.
Multi-layer map control
In order to keep it simple, I used the report from my previous post. Specifically, the version with the standard PushPins. And the only layer I want them to be able to toggle, is the PushPin layer on top of the basic map.
Creating a parameter
Because your want to present an easy solution to your users, I want to create a Boolean parameter that they can use to toggle the PushPin layer. To create this parameter, right-click on Parameters in Report Builder, and choose “Add Parameter”:
In the general options window, make sure you fill in a Parameter Name, a question for your users (so they understand what they need to do), and a Data Type (in this case a Boolean, that’s either True or False):
Because you don’t want to keep your users waiting if they open your report, you might want to give the Boolean a default value. You can do this by adding a default value to your Boolean:
By doing this, the Boolean is True by default. So the user doesn’t have to pick a value if he runs the report for the first time. This might come in handy if you need this as an extra feature in your report, and not a feature you need to configure before the report shows your data.
Now you need to configure your map layer to use the parameter you created to toggle it. Double-click on your map control, and once you see the Map Layers menu on the right, you can do this by right-clicking on “Layer Data”:
Now click on Visibility, and under Layer visibility, click the last option, and press the Fx button:
In the Expression window, fill in the following expression:
Now if you run the report, you’ll see the Boolean appear in the top bar of your report. By default, it’ll show the PushPins:
And if you change the Boolean to False and press “View Report”, you’ll see the may without PushPins:
With a little help from my friends…
This post isn’t just written by me, but also with the help of Valentino Vranken (Blog | @ValentinoV42. He helped me out on Twitter, because my expression didn’t work as expected. So Valentino: I really appreciated your help! Thank you! 😉