is clutter-free web application which provides an easy way to find grid references (e.g. two figure, four figure, six figure) by overlaying the British National Grid on Ordnance Survey mapping. The app also allows for conversion between the UK's native coordinate system and GPS-style* latitude and longitude at the click of a mouse (or tap of a finger). 3XE hopes that this free-to-use web tool will be useful to anyone who works with, or uses in their leisurely pursuits, grid references and or easting/northing* coordinates.

In addition to providing standard grid references and coordinate transformations, the web app is the first of its kind to provide the option of denoting the non-standard 'SS10NW'-style 'cardinal quadrant notation' grid references which will be familiar to those who have worked with large UK raster data sets. For curious bystandards, the need for this notation derives from the situation whereby, in order to keep file sizes manageable, providers of aerial survey data divide their surveyed area into 10km grid squares (e.g. SU97, for Windsor, Berkshire) and then further divide those square into 5km quadrants. This yields, for example, a filename like SU97NW.tiff for the northwestern quadrant of SU97 containing Windsor Castle. The result can be flummoxing for the casual GIS user because, if wishing to load the 5km square to the east of SU97NW, it is not immediately obvious the required file is TQ07NW.tiff. Fortunately, solves that problem.

User interaction design choices ensure that user experience is as painless as possible across desktops, laptops and tablets. For instance, laptop users without mouse wheels or multi-touch hardware may zoom using keyboard shortcuts 1 and 2 saving them from moving the cursor back and forth between the map and the zoom buttons. Similarly, the escape key can be used to close the coordinate information bubble, the app can be fullscreened and converted coordinates are highlighted automatically for easy copying. Though seemingly small, such design decisions are emblematic of 3XE's approach to get GIS off the desktop and onto the web -- designing GIS applications that increase productivity and lower barriers for adoption by making workflows easier.