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Does anyone have a map?

If there is one thing that I really enjoy, it’s exploring data spatially. I really enjoy being able to look at a map and see where clusters are and see if I can find trends or even if there is anything near me. To me, this has been one of the main things that I’ve felt that the ADS is missing on its website. There is such a wealth of spatial information in our database that it only makes sense that we should have a really good map, right?


Well, eventually we will, as soon as I build it.

So what is the plan? I, Teagan, digital archives officer and map enthusiast, will be working towards making a searchable map interface that will work for the ADS Library and maybe more someday, but baby steps. This post will work as kind of a dev library to let everyone know what we’ve (I’ve) been doing towards making this map a reality.

November Update

We chose Leaflet as the software as its both open access and has an existing large community. It’s that community that has allowed us to build what we have so far.

The first step was to determine how the data from our Library would be pulled and displayed on Leaflet. For this we had two options, pull directly from the database or use a csv. Traditionally we pull things directly from our database but the CSV option has a lot of potential for some of our smaller archives. There was also the size to consider; we currently have over 60k spatial points within our database.

Leaflet Map CSV

In the end, we knew how to pull data directly from the database so we decided to try the csv to compare. Below is an example from github that shows what the plugin displays. In short, it pulls data from a csv and requires Lat, Long, and a “Title” field that can be used in a bind-popup as shown. There can be more columns which you can combine in the popup and its usage of PapaParse allows for a large number of points to be displayed.

map csv example showing points with a popup name
Github example of map csv.

Next issue was how do we show more information about each point?

Leaflet Sidebar

We thought that the best way to do this was through the use of a sidebar that could be dynamically filled with other information from the CSV.

leaflet-sidebar example, when a point on the map is clicked, a sidebar appears from the side
Github example of sidebar.

This one was perhaps the trickiest for me. Getting the sidebar to be dynamic as well as the CSS lead to many discussions with the code but we worked it out in the end. There are still some CSS issues to work through but we were quite happy with the way it’s going so far. But 60k points displaying on a full screen map was… messy.

Leaflet markercluster

So we decided to go with clustering, it allowed for grouping of points, multiple points in one location, and it hands a large amount of points well. Plus it’s its really easy to use and implement.

cluster map example showing coloured circled with numbers representing the number of points around it
Github example of markercluster.

The downside to clustering is I’m not a fan of not being able to show multiple types of clustering but the grouping markers and custom markers might work with that. I need to do more work to add the realworld 50,000 plugin into it as well.

What’s next?

We’re entering a busy bit of time but there are a few things I’d like to explore.

  • Investigate what else I can do with markercluster
  • Add in basemaps!
  • See if a search function is possible using csv. Preliminary searches say yes using geoJason but I need to test it.
  • Heatmap? May help cut any lag time and would work better for large areas, like the world view. Go from a heat map then switch to cluster depending on the view.
  • Customise the markers a bit more
  • Test how this would work on the website and sort out the css…
  • Binning regions?


Map as it currently looks with a few clusters and points shown as well as the side bar open showing the title, description, and image.
Featured archive: ACCORD with the Bressay History Group

December Update

Current version of the library map showing a sidebar and thousands of clustered points. Both the points and sidebar include baubles to give a more festive feeling to the map.
Winter holiday draft.

The data

Points, lots of points. This month I tested loading all 63,000+ points into leaflet and it worked far better then I would have initially expected. Marker clustering was able to handle a large amount of points well and I’m interested to see how much more it can hold.

The sidebar in the image above shows the current details from each record: title, Lat/Long, and abstract. Later I’ll see about adding in more details such as links to the record, citations, key terms, authors, etc. At present, there is a stock Christmas image by d3sign there to bring a bit of Christmas cheer but in the future we’ll also need to decide if we add images, logos, etc, and investigate what will be static (appear exactly the same for each point) or dynamically updated (changes for each point, e.g., title)

Custom Markers

Another thing I implemented was the use of custom markers. I’m not sure if the final version will have custom markers but I may use some for grey literature vs journal articles or reference vs full record. A lot of it will depend on what fits best within the map when it’s released and what feedback we hear about how users want to use the map.


Something that I particularly enjoyed was selecting a few basemaps. It’s yet to be finalised about what maps will be chosen to allow users to change the map backgrounds but my favourites include:

Open street map

Open street map baselayer
A classic, love the look and cant go wrong with looking at what else is around the points from a modern perspective.

Voyager without labels by CARTO

Voyager without labels by CARTO basemap
This one is nice because it gives the feel of the current layout of cities and such without any labels that could be distracting depending on what you’re looking at.

OpenTopoMap by Garmin Maps

OpenTopoMap by Garmin Maps basemap
A topographic map for when you want contour lines or a more traditional looking map.

Watercolour by Stamen

Watercolour by Stamen basemap
A lovely basemap that gives the impressions of what is there but allows you to really just focus on the data.

Toner by Stamen

Toner by Stamen basemap
Simple, black and white basemap with only the essentials makes it easy to see where the data is.

Positron by CARTO

Positron by CARTO basemap
Similar feel to the Toner map but with more labels for knowing exactly where you are.


There were a few things that I worked on that I couldn’t get it work with the map in its current form.


I really like the look of this spinning circle to let you know the screen is taking longer then a millisecond to load. I thought it would be better then the bar that comes with the clustering plugin because the loading time isn’t currently long (think a few seconds, max). That said, I’ll have to look into this more because while I had it appear on the map, it never went away, even after the map fully loaded. I’m so close to make it work but it’ll take more time.


Couldn’t get this one to work. The way that the map currently pulls the data is from a csv. The clustering works fine with looking for the column with the correct label headings but heatmap requires there to not be a header. So similiar methods but different implementations. As such, we still want to use heatmap but we’re going to be pulling the data directly from the database rather then loading from a csv.

The knowledge we learned with working with the CSV will be great in the future though as we have a greater potential to allow for our archive pages and Internet Archaeology to incorporate more maps, more easily.

What’s next?

The holidays. I’m going to be taking an extended one so there is unlikely to be a January update but over the new bit I want to looking to:

  • Fixing the loading circle
  • Using geoJason as a search/refinement tool
  • Adding the Heatmap
  • Figure out what an ADS css for the map would be
  • Binning regions?

July Update

Time has flown by.  With all the work on some major updates to our website, the map has had to take a slight pause.

What’s happened?

In terms of progress, not as much as I would have liked.  The loading circle refused to cooperate and while the csv continued to work, there was an issue with how often we’d have to update things.  The heatmap worked but there were difficulties in fixing the zoom level so it would transition from heatmap to clustering.  At least the css is making progress…

What’s next?

We’re headed up to the ADS’s busy time so not much progress will take place in terms of what will be seen by the public.  But in the meantime, might I recommend the ARIADNE Portal?

Heatmap of the UK and Ireland with most of the points being in England
Currently, the Ariadne portal holds 1,064,799 resources that were provided to them by the ADS. It’s a great place to look at what the ADS holds while we continue with our map.