tMapper is a web-based application, converting WW1 trench map references to locations you can visit using a GPS, Google Maps or Street Directions. It will run on a PC, mobile phone or tablet. An internet connection and a modern browser is required.
It supports single conversions, multiple conversions, elevation profiles, Google Street View, modern locations and Excel export. Known limitations appear below and may be addressed at a later date.
Home Page allows any location within the 1,000 yard grid square (abcd), to be in single or double-digits. Eg b.37.11 is assumed to be 37 units left and 11 units upwards from the origin of grid 'b'. Grid b.4.1 is assumed to be 40 units left and 10 units upwards. If relevant, enter it as b.04.01.
Single-Map overlays a description that is removed after a few seconds. Clicking on the marker icon displays it once again. The table below the map also displays a link to McMaster University where you can see all trench maps for the sheet itself (eg Sheet 36c - Vimy). A link to the National Library of Scotland's extensive trench map resources is also provided. Finally, a link to the highly-regarded Muninn project is provided as a comparison. Their conversions and ours lie within a hills-hoist ...
Street View shows a requested location and a Google image. If the Google image is blank, it is because no camera has visited the location, such as in the middle of a field. Manually move the Street View control and all roads will appear highlighted in blue.
Multi-Map displays multiple conversions. It can handle thousands of conversions but only 256 points will be displayed. However all converted points can be exported to Excel. See Single-Map for the information each table contains. In addition, the zoom button allows you to select a location for a higher resolution image. Rows can be sorted by a number of columns.
Elevation Profile joins and charts 2 points to give an idea of the lay of the land between these. This feature is not supported in Microsoft Edge.
Search displays a list of trenches matching your criteria. The search page needs only 3 letters and terms are case-insensitive - pear and Pear will return the same result.tMapper will display a maximum of 32 results, with the trench name, nearest town and map reference. Simply click on the hyperlink for the one you want and tMapper will display it.
Note that the location of a trench system or sector may span a considerable area. As a guide, tMapper displays the central location only. A circle is drawn around the location - the larger the radius, the greater the area representing the sector or line of trenches.
In addition to original work transcribing trench locations into the search engine, the tMapper team acknowledge data from Australian War Memorial, Great War Forum contributors and thanks John Reed for kind permission to incorporate his Gazeteer of the Western Front.
Overlay allows you to change the opacity of an overlaid trench map with the slider. Move the slider left to make the trench map fade and vice-versa.
Note that the current version of tMapper uses the 'quick overlay' Google Maps facility and is a general guide. This version aligns the map as a simple rectangle with equi-latitude NW and NE corners. A later version may align boundaries with increased precision.
The tMapper team acknowledges McMaster University as the origin of a number of these, used under the Creative Commons license.
Individual Burial Locations overlays a heatmap interpreting how many bodies were recovered from an area post-war. It is commonly called a body density map but has no direct correlation with casualties. However, the retrieval of 80,000 human remains immediately after the war is a moving tribute to the ferocity of combat in the Ypres and Somme regions. You can toggle it off and change the colour, intensity or opacity.
The tMapper team thanks John Reed for kind permission to use his painstaking transcription of this data.
Export: tMapper's menu bar allows you to export to Excel. If you have Excel on your device, it will load the tMapper Comma Separated Value (CSV) file for you. The 1st entry is always your single conversion. The next 2 are your elevation profile start and finish respectively. Any bulk conversions appear from the 3rd line onwards.
Utilities: tMapper saves all conversions you have done and they are available on subsequent visits. If you wish to delete them, the 'Clear All Data' will remove these without warning. Note that all menu functions will continue to work but all maps will be blank as they contain no data. Once you have visited the home page and entered values, maps data will re-appear.
Accuracy: This page displays 65 known church locations, together with a test of prediction accuracy, rated from 1-5. The respective values are 8, 8, 29, 11 and 9. This suggests that a prediction for a church spire somewhere on the Western Front will place you on, or close to the church roof.