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Mapbox hosted custom polygons in reports and dashboards

By NICK PLOWDEN posted Thu May 03, 2018 10:22 PM

With Cognos Analytics 11.0.11 users will be able to visualize custom polygons hosted on Mapbox within reports and dashboards! Here’s how you can start visualizing your custom geospatial polygons in Cognos!

If you don’t have a MapBox studio account already the first step would be to create one (each organization/department can host all their polygons on one account). For many of our users the free account with 5GB of storage space should be more than sufficient to host all their polygons.

Then upload your geoJSON custom polygon file to Mapbox as a tileset. Custom polygons in different formats such as .shp and .KML can be easily converted to geoJSON using several open-source software (QGIS is recommended).
- A tile-set is essentially a compiled set of geoJSON optimized to render fast on a browser.
- If your geoJSON is under 5MB, you will also be able to edit the geoJSON directly in Mapbox-datasets through an intuitive UI. Once edited it can be exported into a tileset.
- Each polygon will need to have at least one uniquely identifying property (we recommend that this be an abstract identifier)
- Ensure the tileset is made Public (Tilesets are public by default)

Once you have you tileset created in Mapbox you will need 3 keys from the tileset page.
1 – MapID, 2 – Layername, 3 – Property Name (unique identifier)

Mapbox tileset

In the Cognos Map visualization expand the properties pane and enter the 3 keys from the step above. This

workflow is identical in both Cognos reporting and dashboards.
Then simply drag your Property name (unique identifier) into the locations slot and a measure (s) under the location colour/Point colour/point size slot. That’s it!

Note – if your custom polygons are points then enter the 3 keys in the points layer instead.

Best practices

Do not add any confidential or sensitive information as a polygon property. Although, not common, if your existing geoJSON has sensitive information in its properties, we recommend that you remove them before uploading your polygons to Mapbox. Best practice would be to make the geoJSON property an abstract identifier.

Share the 3 keys to your Mapbox tiles on a need-to-know basis.

For better performance and to guarantee polygons appearing at zoom level 0 (world view) it is recommended to compress larger geoJSON files to less than 10MB. http://mapshaper.org/ is a fantastic free tool to do this.
a. geoJSON larger than 10MB will be set default zoom extents that may not begin at worldview – level 0 (this is a mapbox optimization technique). However, if you want to manually change the zoom extents there are few ways to do so.
i. Tippecanoe APIs (Linux, MacOS)
ii. Download Mapbox studio classic on your desktop (windows) and change min/max zoom levels
iii. Mapbox documentation here: https://www.mapbox.com/help/adjust-tileset-zoom-extent/

To ensure that autozoom works in Cognos reporting we recommend setting the unique polygon identifier as a string value.

For those working with custom polygons in small areas (postcode level) we recommend turning off auto zoom after the initial map render. This will result in a better experience when filtering as the map will not have to reset zoom and pan in multiple times.