Introduction
For the CARTO lab, I chose a dataset from the Fish and Wildlife Service, through data.gov, that reports the location of critical habitats for threatened and endangered species. The term “critical habitat” was defined in the Endangered Species Act as a geographical area occupied by a threatened or endangered species “on which are found those physical or biological features (I) essential to the conservation of the species and (II) which may require special management considerations or protection.”
My goal was very straightforward. I wanted to create an interactive map, displaying the location of these critical habitats, that would be useful for both expert users and novices looking to explore the topic.
Informative Visualizations
I began by looking for visualizations to inform my approach. The Adirondack PRISM – Invasive Species Distribution Map takes a simple approach. The interactive map allows users to zoom into an area of interest. Relevant points are clearly marked, categorized by color, and can be clicked on for additional information.
A map of the species of trees in NYC provides a more interactive experience. Hover labels for each tree are available by default, or the user can choose to narrow the result by species. It’s also interesting to note that the size of each point corresponds to the diameter of the tree.
According to their About page, antmaps.org aims to “provide an intuitive and efficient framework for professional and amateur myrmecologists to visualize the known distribution of ant species or higher taxon.” This map is most similar to what I wanted to create. It makes use of a legend to provide more detail. It also provides minimal information through hover labels, and more in depth information through click labels. Users also have the option to filter by subfamily and genus.
Methods and Discussion
The FWS data I used are available as a zip file, including both line and polygon data, and matching shapefiles. I ended up removing the line data, for styling consistency.
After I uploaded the data, the basemap defaulted to a Positron style map, which I left as it was. The fill colors defaulted to purple/blue/green color scheme based on the “listing” column, which represents the endangered status of the species in a particular habitat. I titled the map “FWS Critical Habitats” and added a legend.
I added a widget, using data from the column “comname”, which lists the common name of the species found in each critical habitat. A single species can be listed for more than one habitat, so I chose the Count operation for the widget. I selected the dynamic behavior option, so a potential user can select a given species and see the isolated results in real-time.
Out of all the records, 112 did not have common names listed, so I added a widget to filter by scientific name as well.
The widgets do not not provide a completely intuitive experience, at least not as the only means for exploration. They only display 5 out of 425 common names by default. The other 420 have to be accessed using the Search feature. So, the user either needs to have access to the full list of common names in the dataset, or have prior knowledge of the species that have a critical habitat, or just search by trial and error. Finally, when a particular common name is isolated using the widget, it is can be difficult to determine where on the map the critical habitat appears because most of the habitats are relatively small. These problems are partially resolved when the user zooms into specific areas – the number of common/scientific names available in the filter is reduced to only those that appear in the section of the map that is currently visible. Regardless, the map in this state would be more useful to experts who are already familiar with the species and areas, than it would be for novice users.
To facilitate a more novice-friendly approach to the map, I added labels through Georeference analysis. I chose hover labels in the light style for the Common Name, to allow easy access for users who aren’t necessarily looking for in depth information. I chose click labels – in a contrasting style for distinction – to include the scientific and federal information.
The interactive version of the map is available publicly through CARTO.
Future Directions
This is a fairly straight forward dataset. It would be interesting to have a second data set to compare it to. There is an abundance of ecology related data available on data.gov. Future work could explore the relationship between critical habitats and invasive species, climate resilience, groundwater depletion etc. For this to work, the fill color would need to be changed to a single solid fill for the three critical habitat types. A second color would be used to differentiate the dataset to be compared. Alternatively, it would be interesting to explore the relationship between several similar datasets, and adjust the visibility of layers to facilitate the desired comparisons. Hover and click labels would still be necessary to provide more information.
It would also make the map more educational to connect another dataset with additional scientific information about each species (taxonomy, conservation projects related to each habitat, etc.) that could appear in the click labels.