An atlas of Wales in Welsh - data on OpenStreetMap

I recently saw a tweet by @mikeparkerwales about a new atlas of Wales in Welsh being prepared by @dafyddelfryn.

A Gaelic map of Scotland has also recently been produced by Paul Kavanagh.
As well as my own work, there is also Justin Cozart's map of Cornwall in Cornish.

I have produced a set of cycling maps of Wales where I used the placenames from OpenStreetMap. My procedure was to prefer the Welsh name, i.e. use the name:cy tag where it existed, otherwise the name tag.

I couldn't actually remember how I had got the Welsh names, since they are not on the standard shapefile downloads from geofabrik.de that I usually have used.

However the full set of tags are available by using the .pbf file available at download.geofabrik.de/europe/great-britain.html which needs a little more work, firstly to convert to the full XML by osmconvert, and then to turn that into SpatialiteDB format. The tutorial here explains a little of how this is done.
This process can be horribly inefficient, since a large .pbf file is downloaded, which is processed into an even larger XML. I think there are other ways to do it which avoid this which I may look into in future.

For the Welsh names, it is necessary to look for the name and name:cy tags, and maybe also name:en tags, which exist for some places, though this is usually just a duplication of name. A very few places have an alt_name:cy tag, where there is more than one Welsh name current for a particular place.





See also WikiProject Wales on the OpenStreetMap wiki. Unfortunately neither the Welsh language OpenStreetMap rendering at http://brasskipper.org.uk/cyosm or the multilingual test page by Jochen Topf currently seem to be working.

Here are some basic renderings of placenames in QGIS, using the places.shp from the geofabrik.de shapefile of Wales, and 'joining' this to the name:cy, name:en and alt_name:cy tags from the Spatialite version.

Mid-Wales. Most names only have the name tag, and where a separate name:cy tag exists, the name tag is generally the English name, although in the case of Ffwrnais, it is a bilingual form. Where name:en exists, it is usually a duplicate of name, but in one case (Pontfaen /  Forge), name:cy and name:en tags but no name. Barmouth has an alt_name:cy tag of "Y Bermo" defined.

Holyhead. Similarly where name:cy exists, name is sometimes the English version and sometimes a bilingual form.

Cardiff. Many bilingual names are in evidence, the general practice here seems to be to use name:cy for the Welsh name and name for the English name, and where name:en exists, it is usually simply a duplicate of name.

Bridgend. The remaining two places in the populated places shapefile that have an alt_name:cy defined are here.

Using QOSM to provide OpenStreetMap basemap in QGIS for my slopelines project

In previous posts I have described how I have used a segmented DEM with RSGISlib, a method originally developed as part of my MSc dissertation on Martian glaciers, for visualising slopes on Earth.

I have been looking at these again, and have produced a few maps with the QOSM plugin, which dynamically loads OpenStreetMap tiles into QGIS.

These maps below were produced with the Thunderforest Outdoors rendering. The slopelines are as previously, red for convex slopes, blue for concave, with thicker lines denoting steeper slopes.

Previous versions of this had used a version of OpenStreetMap that I was preparing myself from the source data within QGIS. Using the basemap tiles I can focus on adapting the visualisation of the slope lines themselves a bit more.

Bodmin Moor

Camborne and Redruth, including Carn Brea and Portreath

Penzance

Truro

A close up of Truro

For a while I thought the QGIS bug I found had recurred which meant that the arrows had disappeared. However it was something wrong in my data dependent styling, not sure how it happened. Once fixed, I show the slope direction with arrows, which is only possible up to about 1:10,000 otherwise the rendering struggles:

Indicating the downslope direction with arrows.

Delabole, showing the slate quarry.

St. Ives

Aberystwyth, Wales

Cadair Idris, Wales

A wider view of Cadair Idris, too small a scale to allow plotting the arrows.

Pen y Fan, Brecon Beacons, Wales

Some more work in progress re: Cornish GIS maps

Here is a little more about my work in progress in generating maps of Cornwall in QGIS.

I have downloaded various Ordnance Survey VectorMap data, along with some layers which come from OpenStreetMap. The OS VectorMap has layers including woodland, tidal water, surface water polygons (e.g. lakes and reservoirs), foreshore and surface water lines (rivers etc.) and others.

These is more comprehensive than OpenStreetMap, however the OpenStreetMap vector layers come with names associated with them in the attribute table in some cases. Certain of the OS VectorMap layer objects will exist in the VectorMap 'Named Places' shapefile, but as points rather than as names in the attribute tables of the polygons themselves.

In the map below I have used the woodland polygons from the OS VectorMap and the ones from OpenStreetMap, but only the OpenStreetMap ones are labelled, since only they have names in the table.

I have also generated contours based on the Shuttle Radar Topography Mission, 1 arcsecond data, which is now freely available for most of the world. It is also possible to use OS Terrain50 contours, which generally appear smoother than these ones, however given these are released in individual squares, I found myself having so many vector layers in the rendering that QGIS crashed.

The Falmouth area, using contours from SRTM 1 arcsec

There is a fairly large amount of data entry to be done to put the names in Cornish, and beyond the list that has already been published by MAGA I would expect it to be slower work.

The OS VectorMap Named Places shapefile for the SW grid square has 2759 entries, of which 679 are various geographic features and the remainder are populated places.

The OpenStreetMap files have approximately 122 named woodlands in Cornwall (of 810 polygons, of over 9000 in the SW grid square alone for OS VectorMap), 56 named water polygons (of 327), 21 parks (of 45), 242 named waterways (of 2923) as lines (some duplicate names for different parts of a feature), and 1337 named places (of which I have already entered 421 in Cornish based on the MAGA Kernow list). There are 10342 named roads in Cornwall from the Open Street Map data.

Georeferencing a tithe map and overlaying modern mapping in QGIS

The National Library of Wales recently released a tithe map of St Woolos, Newport to Wikimedia Commons. There is a crowdsourced project to digitise, georeference, and transcribe the field names from these maps, however I wanted to try out geoferencing in QGIS with its georeferencing plugin, partly because it may be useful in the Taves an Tir project that Kowethas an Yeth Kernewek are doing, since scans have also been made of the tithe maps of Cornwall.

After downloading the full resolution (16,298 × 22,877 pixels) tithe map of St. Woolos, I used the QGIS georeferencer plugin which works by matching manually chosen points between the scan, and a map. In this case I used a map of the UK road network ultimately from OpenStreetMap via www.mapcruzin.com, as well as some of the OS VectorMap data. This includes railways, woodland areas and parks shown below. I styled the road map in QGIS depending on the category of road.

I used 8 points, finding road junctions that I could match between the two maps and a Helmert transformation (more information from QGIS web documentation). It was clear when I did this that one of my points was incorrectly placed, which isn't too surprising given the road network has changed since 1845, but discarding this gave a good result.

I've also downloaded some of the 1 arcsec resolution Shuttle Radar Topography Mission data, which has recently been made available for most of the world, including the British Isles, and transformed this to a contour map in QGIS.

Below is a map of a portion of the St. Woolas tithe map area, with the modern road network overlaid along with OS VectorMap data for railways, woodland, surface water and parks.

There are many options in QGIS for feature labelling, for instance it is possible to suppress labelling of small features to avoid label overcrowding, which makes it label street names selectively. 

Link to higher resolution version (8MB png file)

Aside - Welsh language names in OpenStreetMap

OpenStreetMap does have some Welsh language names, if the name:cy tag is used. It is possible to see these using the Multilingual Map Test site by Jochen Topf.
It is slightly involved to extract this from a download from http://download.geofabrik.de/ because it is in an 'other_tags' column along with various other things and a bit of string slicing is needed to get it out.
The name:cy tag is only used where the Welsh language form of the place differs from the version commonly used on English maps.