The clustered markers in leaflet are jarring (I like them, but when I show maps I make my wife she finds the transitions nauseating).
The default heatmaps for these maps are bad. Heatmaps should use filled contours so the gradations are more easily identified. (Continuous raster maps are blobby.) See the ascii glyph map in this post, https://andrewpwheeler.com/2015/06/12/favorite-maps-and-grap.... I think those should be static for various levels of zooms as well, and not recalibrated when zooming.
Another option (not shown here) is to just use polygons and aggregations, and when zoomed in can turn on that point layer (or just have it appear). Or can just make actual clusters (like DBSCAN).
Yeah, whatever approach to heatmaps was taken for the example in the article needed some work. It basically just turns into red when you zoom out. Whereas the opaque dots actually give you a nice sense of varying density.
I really enjoyed this article because it happens to focus on a problem I'm knee-deep in at the moment, although I'm not ready to throw clustering out the window just yet.
There's a deeper issue which the author touches on, showing too much information on a map. This is possible independent of technology limits depending on what level of focus you wish each point to have. For many maps, showing a bunch of small points is an elegant solution, the map turns into more of a data visualization. But a bunch of points tells you very little about a particular thing.
If Google Maps just gave you a bunch of points instead of labels, it would be less functional. Every city would just be a large collection of points. Great, that might be interesting if you want to visualize how the locations are distributed in the region, but you are probably looking at the map because you want to find a particular thing.
Clustering is the natural choice: show the most important thing out of all the points in the area. A label is important, a big circle with a number in it is the worst out all the options discussed. My issue with Google Maps is that there is no visual indicator that there are other points there, and that seems to be largely driven by the fact that it is a marketing platform.
I'm working on a map that uses a hybrid approach. Each map has a narrow focus and is tied to a particular community/interest: concerts, bear sightings, hostels, food trucks, whatever you want. For each point of focus, there is a label and a thumbnail. Showing a bunch of these all in the same place is a bad user experience, so it ranks them and shows the most important one, and the thumbnail is replaced by a number indicating there are other points of focus in the vicinity. Users can click on the item to get a side panel that shows a listing of all the points.
There are also other points on the map that are secondary to its focus, public transportation vehicles and other location points that the user can filter. These are displayed as little dots, similar to the example that the author provides. If you zoom in far enough, they become more than just dots.
In designing the user experience, I tried to make it like a map experience that you might find in a strategy game. Each focus point is like a unit that will bring up more information in a side panel. If there is more than one unit there, show an overview of the units. It's a work in progress, but I'm happy with the result so far.
WebGL is a major upgrade for maps. But as an old school web maps person, the obvious solution to the first problem (nearby points clustered even on the city level) is to use the maxZoom option which is in most clustering libraries.
I have an app that is heavily map-based. It's an iOS app that uses Apple Maps (I know, I know, controversy, yadda, yadda; but there's a good reason -many of them, in fact- that I use Apple Maps).
I found that the built-in AM clustering truly sucks, so I wrote my own. It's not perfect, but delivers a much better experience than the native one.
It does save a purpose. For example in the OP's non-clustering example all of the Britain is covered in dots, I'm talking at the highest zoom level, while the Atlas Obscura version, the one that uses clustering, does a better job of providing data by mentioning how many points that general area contains.
In such cases I generally prefer displaying counts of points in defined areas, rather than using clustering (e.g., when zoomed out, show counts per country, and when zoomed in more show counts for states or equivalent sub-national areas).
If you have less than hundreds of thousands of points, you can probably get away with drawing individual dots on the map. Computer screens are high res.
Then, the dots should be less than 100% opacity, which helps convey density wherever they overlap. It's feasible in overpass turbo with its rather simplistic MapCSS, so it should be possible in proper web mapping libraries.
>You don’t have to cluster anymore. You can just be.
Try to get Google Maps or Apple Maps running on a phone with more than 200 Markers/Annotations, then come back to me with that. Their performance is fucking dreadful. Google Maps released a new renderer that just OOMs if you're rendering a Polyline with 5k segments. Decimate it or face consequences.
As far as I know, MapBox is about the only one that has tolerable performance. Anyone else doing heavy work and using the gmaps SDK is figuring out tricks: overlay rendering (drawing on a canvas above the map, which requires expensive RPC calls to get visible bounds / map projection which makes performance shit if you're not careful and always lags a frame behind), intense caching of marker descriptors, careful management of markers (dropping 200 Markers from scrolling the map + adding 200? Enjoy your main thread work that freezes the map), etc, etc.
The clustered markers in leaflet are jarring (I like them, but when I show maps I make my wife she finds the transitions nauseating).
The default heatmaps for these maps are bad. Heatmaps should use filled contours so the gradations are more easily identified. (Continuous raster maps are blobby.) See the ascii glyph map in this post, https://andrewpwheeler.com/2015/06/12/favorite-maps-and-grap.... I think those should be static for various levels of zooms as well, and not recalibrated when zooming.
Another option (not shown here) is to just use polygons and aggregations, and when zoomed in can turn on that point layer (or just have it appear). Or can just make actual clusters (like DBSCAN).
I have a map I made on my website that shows these (with various interaction tooltips/hover), https://crimede-coder.com/graphs/DurhamHotspots (hotspots of crime in Durham, NC). And an explanation of the cartographic decisions and when to use the different techniques, https://www.youtube.com/watch?v=mBm6sTR08BI
Yeah, whatever approach to heatmaps was taken for the example in the article needed some work. It basically just turns into red when you zoom out. Whereas the opaque dots actually give you a nice sense of varying density.
I really enjoyed this article because it happens to focus on a problem I'm knee-deep in at the moment, although I'm not ready to throw clustering out the window just yet.
There's a deeper issue which the author touches on, showing too much information on a map. This is possible independent of technology limits depending on what level of focus you wish each point to have. For many maps, showing a bunch of small points is an elegant solution, the map turns into more of a data visualization. But a bunch of points tells you very little about a particular thing.
If Google Maps just gave you a bunch of points instead of labels, it would be less functional. Every city would just be a large collection of points. Great, that might be interesting if you want to visualize how the locations are distributed in the region, but you are probably looking at the map because you want to find a particular thing.
Clustering is the natural choice: show the most important thing out of all the points in the area. A label is important, a big circle with a number in it is the worst out all the options discussed. My issue with Google Maps is that there is no visual indicator that there are other points there, and that seems to be largely driven by the fact that it is a marketing platform.
I'm working on a map that uses a hybrid approach. Each map has a narrow focus and is tied to a particular community/interest: concerts, bear sightings, hostels, food trucks, whatever you want. For each point of focus, there is a label and a thumbnail. Showing a bunch of these all in the same place is a bad user experience, so it ranks them and shows the most important one, and the thumbnail is replaced by a number indicating there are other points of focus in the vicinity. Users can click on the item to get a side panel that shows a listing of all the points.
There are also other points on the map that are secondary to its focus, public transportation vehicles and other location points that the user can filter. These are displayed as little dots, similar to the example that the author provides. If you zoom in far enough, they become more than just dots.
In designing the user experience, I tried to make it like a map experience that you might find in a strategy game. Each focus point is like a unit that will bring up more information in a side panel. If there is more than one unit there, show an overview of the units. It's a work in progress, but I'm happy with the result so far.
WebGL is a major upgrade for maps. But as an old school web maps person, the obvious solution to the first problem (nearby points clustered even on the city level) is to use the maxZoom option which is in most clustering libraries.
I have an app that is heavily map-based. It's an iOS app that uses Apple Maps (I know, I know, controversy, yadda, yadda; but there's a good reason -many of them, in fact- that I use Apple Maps).
I found that the built-in AM clustering truly sucks, so I wrote my own. It's not perfect, but delivers a much better experience than the native one.
There are excellent examples of the problem in Edward Tufte's "Envisioning Information". Have a look at http://blah.ksteinfe.com/181106/tufte_envisioning_informatio... for a few snippets of it, then buy the book.
Clustering is only asked for by someone that has no interest in or understanding of the data.
It does save a purpose. For example in the OP's non-clustering example all of the Britain is covered in dots, I'm talking at the highest zoom level, while the Atlas Obscura version, the one that uses clustering, does a better job of providing data by mentioning how many points that general area contains.
In such cases I generally prefer displaying counts of points in defined areas, rather than using clustering (e.g., when zoomed out, show counts per country, and when zoomed in more show counts for states or equivalent sub-national areas).
If you have less than hundreds of thousands of points, you can probably get away with drawing individual dots on the map. Computer screens are high res.
Then, the dots should be less than 100% opacity, which helps convey density wherever they overlap. It's feasible in overpass turbo with its rather simplistic MapCSS, so it should be possible in proper web mapping libraries.
The demo shows exactly that with the density dots, no?
>You don’t have to cluster anymore. You can just be.
Try to get Google Maps or Apple Maps running on a phone with more than 200 Markers/Annotations, then come back to me with that. Their performance is fucking dreadful. Google Maps released a new renderer that just OOMs if you're rendering a Polyline with 5k segments. Decimate it or face consequences.
As far as I know, MapBox is about the only one that has tolerable performance. Anyone else doing heavy work and using the gmaps SDK is figuring out tricks: overlay rendering (drawing on a canvas above the map, which requires expensive RPC calls to get visible bounds / map projection which makes performance shit if you're not careful and always lags a frame behind), intense caching of marker descriptors, careful management of markers (dropping 200 Markers from scrolling the map + adding 200? Enjoy your main thread work that freezes the map), etc, etc.
First party map tools are absolute dog shit.