This article currently lives as a video tutorial here:

In this tutorial, you will learn how to add a custom boundary to a map. You can do this using KML or KMZ layers. These files are easy to upload, versatile and can be exported from most GIS tools. They can be used to add multiple layers to your map for users to see and interact with as well as set the boundaries for public participation on your map. Each layer defines a new area, which is then converted behind the scenes to a singular boundary area. 

In the steps below, we will add a .KML/Z file to a map and convert it to a boundary.

Please note that there are several constraints on KML files used on our system in addition to file size. There can be issues if there are too many objects on the map for Google Maps to handle.

  • Maximum fetched file size (raw KML, raw GeoRSS, or compressed KMZ): 3MB

  • Maximum uncompressed KML file size: 10MB

  • Maximum number of network Links: 10

  • Maximum number of total document-wide features: 1,000

In the map dialog, click Add New KML or KMZ file:

You can either drag & drop a file into the box, or select a file from your computer. Be patient while the file uploads in the background.

After it has been uploaded, you can zoom back into your project to the area you know contains the boundary - e.g., Jacksonville.

NOTE: You may not initially be able to see the boundary. To solve this problem, in the Map Layers section, click the ellipsis to the right of the map layer and click Make Map Boundary. This option allows you to make the file you have imported the map boundary.

Please note that while KML and KMZ visual appearance can be customized for map layers, these changes should be performed in a GIS tool prior to upload. If the file cannot be used as a map boundary, you will be prompted to simply the file into a singular boundary in your mapping tool before trying to upload again. Alternatively, you might consider using the boundary-drawing tool instead of using your own file.

Now you can see how the various layers in the KML/KMZ file have been converted to create a  boundary within which users can interact with your map (demarcated by the red lines below. As you can see, the boundary comprises multiple shapes.)

Note that these boundaries will reflect the color attributes of the initial KML file. To change the appearance, you will need to set up those appearance properties in the GIS program where the file originated before uploading it here.

To make sure users can see the boundary, check the box for Show map boundary to users. This will allow users to see the boundary set by the file.

Now you can go back and view your map questions, making sure they are working as expected. Click View Live Site in the upper-right of the project to view your project with the mapping question as the users will see it:

Note: Participants will only be able to draw lines or add points within the boundaries created by your KMZ file. 

Happy mapping!

See also:

How to load GIS shapefiles (.KML) for an interactive map question

How to download map pin data from an Interactive Map question

How to pull KML data from a map question

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