Week Beginning 12 April 2021

I’d taken Monday and Thursday off this week to cover some of the school Easter holidays, and I also lost some of Friday as I’d arranged to travel through to the University to pick up some equipment that had been ordered for me.  So I probably only had about two and a half days of actual work this week, which I mostly spent continuing to develop the content management systems for the new Comparative Kingship place-names project.  I created user accounts to enable members of the project team to access the Scottish CMS that I completed last week, and completed work on the 10,000 or so place-names I’d imported from the GB1900 data, setting up a ‘source’ for the map used by this project (OS 6 inch 2nd edition), generating a historical form for each of the names and associating each historical form with the source.  This will mean that the team will be able to make changes to the head names and still have a record of the form that appeared in the GB1900 data.

I then began work on the Irish CMS, which required a number of changes to be made.  This included importing more than 200 parishes across several counties from a spreadsheet, updating the fields previously marked as Scottish Gaelic to Irish and generating new fields for recording ‘Townland’ in English and Irish.  ‘Townland’ also had to be added to the classification codes and a further multi-select option similar to parish needed to be added for ‘Barony’.  OS map names ‘Landranger’ and ‘Explorer’ needed to be changed too, in both the main place-name record and in the sources.

The biggest change, however, was to the location system as Ireland has a different grid reference system to the UK.  A feature of my CMS is that latitude, longitude and altitude are generated automatically from a supplied grid reference, and in order to retain this functionality for the Irish CMS I needed to figure out a method of working with Irish grid references.  In addition, the project team also wanted to store another location coordinate system, the Irish Transverse Mercator (ITM) system, and wanted not only this to be automatically generated from the grid reference, but to be able to supply the ITM field and have all other location fields (including the grid reference) populate automatically.  This required some research to see if there was a tool or online service that I could incorporate into my system.

I discovered that Ordnance Survey Ireland has a tool to convert coordinates here https://gnss.osi.ie/new-converter/ but it doesn’t include grid references (e.g. in the form F 83253 33765) and although there is a downloadable tool that can be used at the command line I really wanted an existing PHP or JavaScript script rather than having to run an executable on the server.  I also found this site: http://batlab.ucd.ie/gridref/ that can generate latitude and longitude from an Irish grid reference, and it also has an API that my scripts could connect to (e.g. http://batlab.ucd.ie/gridref/?reftype=NATGRID&refs=F8325333765) but it doesn’t include ITM coordinates, unfortunately.  Also, I don’t like to rely on third party sites as they can disappear without warning.  This site: https://irish.gridreferencefinder.com/bing.php allows you to enter a grid reference, latitude / longitude or ITM coordinates and view various types of coordinates on a map interface, but it’s not a service a script can easily connect to in order to generate data.

I then found this site: https://www.howtocreate.co.uk/php/gridref.php which offers a downloadable library in PHP or JavaScript that allows latitude, longitude and ITMs to be generated from Irish grid references (and back again, if required).  This is the solution decided to add into the CMS, after a certain amount of trial and error I managed to incorporate the JavaScript version of the library and update my CMS so that upon entering an Irish grid reference the latitude, longitude, altitude (via Google Maps) and ITM coordinates were automatically generated.  I also managed to set up the system so that the other fields were generated automatically if ITM coordinates were manually inputted.  I think all is now working as required with the two systems, and I’ll need to wait until the team accesses and uses the systems to see if further tweaks are required.

I also continued to work on the Books and Borrowing project this week.  I’d been in discussion with the Stirling University IT people about setting up a IIIF server for the project, and I heard this week that they have agreed to this, which is really great news.  Previously in order to allow page images to be zoomed and panned like a Google Map we had to generate and store tilesets of each page image at each zoom level.  It was taking hours to generate the tilesets for each book and days to upload the images to the server, and was requiring a phenomenal amount of storage space on the server.  For example, the tilesets for one of the Edinburgh volumes consisted of around 600,000 files and took up around 14GB of space.  This was in addition to the actual full-size images of the pages (about 250 at around 12MB each).

An IIIF server means we only need to store the full-size images of each page and the server dynamically chops up and serves sections of the image at the desired zoom level whenever anyone uses the zoom and pan image viewer.  It’s a much more efficient system.  However, it does mean I needed to update the ‘Page image’ page of the CMS to use the IIIF server, and it took a little time to get this working.  I’d decided to use the OpenLayers library to access the images, as this is what I’d previously been using for the image tilesets, and it has the ability to work with a IIIF server (see https://openlayers.org/en/latest/examples/iiif.html).  However, it did take some time to get this working, as the example and all of the documentation is fully dependent on the node.js environment, even though the library itself really doesn’t need to be.  I didn’t want to convert my CMS to using node.js and have yet another library to maintain when all I needed was a simple image viewer, so I head to rework the code example linked to above to strip out all of the node dependencies, module syntax and import statements.  For example ‘var options = new IIIFInfo(imageInfo).getTileSourceOptions()’ needed to be changed to ‘var options = new ol.format.IIIFInfo(imageInfo).getTileSourceOptions()’.  As none of this is documented anywhere on the OpenLayers website it took some time to get right, but I got there in the end and the CMS now has an OpenLayers based IIIF image viewer working successfully.