Looking for iNaturalist observation map visualisation suggestions

General
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the api.inat.org and api.gbif.org URLs above won’t actually take you anywhere. but they do provide a GIS tool – in this case, ArcGIS Online – the instructions needed to get map tiles from iNat and GBIF.

you may have noticed that when you load many online maps, they get rendered a section or a tile at a time, not all at once. as you pan beyond the original extent of the map, new sections or tiles get loaded and added to the map. as you zoom in and out, new tiles get loaded to provide a better representation of the map at the given zoom level.

you’ll notice in the tile URLs i provided above, they all contain a {level}, a {col}, and a {row}. ArcGIS will dynamically replace these with a zoom level, an x value (or column index), and a y value (or row index). that tells the API to return a map tile that represents a particular section of the Earth at a given zoom level. when the API provides ArcGIS that tile (usually a picture file – in these cases, all *.png files), ArcGIS puts that tile on the appropriate place in the map, along with all the other tiles needed to fully display the map.

here’s how you can create a map with one of these tilesets in ArcGIS Online:

  1. go to https://www.arcgis.com
  2. at the top of the screen, find Maps, and click on it. (you don’t have to sign in.)
  3. that should get you to a screen with a blank map. at the top right of that screen, click Modify Map.
  4. that wll add some editing options to the toolbar below. find Add in that tool bar (on the left side of the screen), and click on that, then select “Add Layer from Web” from the drop list.
  5. that will give you a pop up. in that pop-up, select “A Tile Layer”, then fill in the URL (using one of the URLs i provided before), a title for it (which is what show up in the left Contents pane in the screenshots), and credits (which is what shows up in the bottom right corner of the map in the screenshots). then click Add Layer.
  6. finally, you may want to use a basemap that is less busy than the default topo basemap. you can either select one by clicking the Basemap button in the map toolbar, or searching for one via Add > Search for Layer. (ArcGIS has lots of layers available.)

if you don’t like ArcGIS, you can also do something similar in other GIS tools. the specific steps will differ, of course, but the concept is the same. (the URLs may differ in the other tools, too. for example, QGIS and Leaflet.js expect {z}, {x}, and {y} in the URL instead of {level}, {col}, and {row}.)

hope that helps. if you have other questions, feel free to ask.

also note there are a few more advanced things that can be done. for example, you can use different tilesets for different zoom level ranges. so for example, the hexagons that GBIF provides may look okay at that size in my example at a continent level, but they might look too much like points at a higher (more granular zoom level). so you might choose to use relatively bigger hexagons at higher zoom levels by changing the hexPerTile value in the URL (smaller values result in bigger hexagons in this case). you can also modify the transparency of the tiles within your particular GIS tool.

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