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Born-digital documents. Screenshots from Google Earth and Oxygen.
Most
mol:
prefix and accessed through the web application
with their id + .xml
.
The molagas prefix points to the shape representation of a location on
Links to page-images in the Chadwyck-Healey
Links to page-images in the
The mdt (
The mdtlist (
_subcategories, meaning all subcategories of the category.
The molgls (
This molvariant prefix is used on
This molajax prefix is used on
The molstow prefix is used on
Our editorial and encoding practices are documented in detail in the Praxis section of our website.
Any place on the surface of the earth can be located in terms of three coordinates: latitude, longitude and elevation (height above sea level). In most of our work, we are only concerned with the first two, latitude and longitude, because we don’t (currently) envisage any rendering or data processing that would make use of elevation.
Traditionally, latitude and longitude were expressed in degrees, like this:
51°30'49.25"N
0° 5'58.42"W
In modern GIS systems, latitude and longitude are expressed in decimal numbers, which look like this:
51.513557
-0.098369
Coordinates like this are usually comma-separated, like this:
51.513557,-0.098369
51.513557,-0.098369,0
In our work, we usually use Google Earth to find the geolocation of places. Here’s a screenshot of Google Earth showing St. Paul’s Cathedral:
The first thing we want to do is to make sure that Google Earth will use decimal coordinates instead of the traditional degrees; that will make our job easier. Click on
To find the coordinates of this place, the first thing we need to do is to create a
Place the pushpin where you want it to go, and you’ll see that the lat/long coordinates appear in the dialog box, and also at the bottom of the map image. You can copy the latitude and longitude numbers (without their
Where do you put them in your TEI file? If you open up the file for St. Paul’s Cathedral,
For small locations such as individual houses, it is often sufficient to use a single point to identify the location on the map. However, for larger buildings, streets and other types of location, we want to provide more detail. Essentially, we want to draw an outline around the object. We’ll do that now, for St. Paul’s.
An outline is basically just a list of point coordinates, separated by spaces. So a triangle around the dome of St. Paul’s might be specified like this:
51.51391527182066,-0.09834042321448383
51.513532825929,-0.09863498228599121
51.51352062534084,-0.09800392197454352
51.51391527182066,-0.09834042321448383
So how do we create shapes in Google Earth, and how do we get their coordinates out?
First, we have to create a polygon, in the same sort of way that we previously created a placemark. Click on the
Now, Google Earth does not helpfully provide you with the output coordinates when you create a polygon. We have to go through rather a convoluted process to get them. First, give your new polygon a name in the dialog box, and press
Now we’re going to save this place as a KML file. Right-click on the place you created, and choose
Now if you look at the file, you’ll see its
You may have seen, and may even have used, the //name
in the XPath box and press return, Oxygen will list all the
However, this text box is not very big, and we’ll need to enter a long XPath expression to do our work, so we’re going to use the
Make sure you select string-join(for $c in //coordinates[1]/tokenize(normalize-space(.), '\s') return concat(tokenize($c, ',')[2], ',', tokenize($c, ',')[1]), ' ')
Now right-click on the result, and choose
Easy, right? Here’s a more realistic example, representing the real outline of St. Paul’s:
If you’re dealing with a location which is very long and thin, such as a street, you could define it as a very long, thin polygon, but that’s a lot of unnecessary detail. It’s probably better to define it as a path. You can do that in exactly the same way you create a polygon, but using