Program History

This page provides information about the contour maps which are available from this site as a free download - what they are, how they came about, and what use you can make of them.

A Dedication from Dave Storey, who compiled the maps: Dave Storey's father, Bert Storey, died suddenly, at home, on 22/January/2006, at the age of 78.  This page is dedicated to his memory, and to all the others who have gone before us - truly we can achieve what we do only because of them ...

This page is also, following the suggestion of Dave Storey, respectfully dedicated to the memory of SMC member Rob Milne, who died of a heart attack on Mt Everest in June 2005. Rob encouraged Dave to compile the data, and tested early results.

Changes from 1.2 to 2.0

I'm now using revised NASA SRTM V2 height data - 75% less voids (although area North of 60N is still mostly absent)

Added 'Water Body data' from NASA to each tile. This is LARGE lochs, lakes, oceans, and rivers. NASA also used this to zero the height data in most of the oceans. As a result the previous 'coastline' overlay is no longer required (except for the small part of Shetland North of 60N which has usable contours - no Water Body Data for that area.)

Contours are now derived from a finer height grid. The 3 arcsecond * 3 arcsecond SRTM grid (about 60*90m at our Latitude) has been subdivided into 2 wide by 3 high (thus about 30m square) points, which are interpolated using a 36-point spline (i.e. taking account of the nearest 6*6 grid of SRTM datapoints). The resulting finer grid was then contoured as before (using 3DEM and DEM2TOPO). This gives 'rounder' contours, which take account of local gradients and gradient changes .. however small features will still be missing, since you can only 'round' what was seen to be there, not 'invent' things which were too small to get measured in the first place.

I've changed the tile numbering from 13xxxxxx to 14xxxxxx, just in case you really want to install both 1.2 and 2.0 versions into the same mapsource installation (if tiles have the same number, mapsource will die, very messily). Since the new tiles are, on average, only 200KB larger than the old ones, I really don't recommend having both installed.

Tiles also have names like 'Kent and Essex' based on some local feature. Bear in mind though that the tiles are 1 degree square, so the 'Manchester' tile has 'Chester' on the same tile!! Apologies if your favourite town is on a tile with some other name - that's the way it goes!

Changes from 1.1 to 1.2

Fixed problems with incorrect contours in some areas where 'Blackart' had generated artefacts (probably driver error by me) Added .reg file to improve ease of installation.

Changes from 0.1a to 1.1 ..

There is now a 'voids' map showing where the srtm data did not exist.
Contouring in 'void' areas is better.
Some peak/mountain/hill grid references have been fixed (and many spellings). Much more remains to be done.
The overview map has actual place names, and a coastline.
Zooming in/out in Mapsource should work better.

The files are for use with a GPS unit, and you will need to be conversant with the use of these and the software accompanying the unit. This page is written in conjunction with Garmin models and software. Also, we are almost certain that the .reg file will only work with Win XP and Win 2000. Please let us know if you find out otherwise.

Using the free Contour files

Background

Basically they are transparent contour maps covering the whole of the UK and the Republic of Ireland. David Storey started doing this because he couldn't get any topo maps for his Garmin GPS for Shropshire, where he's surveying rights of way for the Council for amusement. Contour maps for the rest of the UK just sort of happened. He's a retired computer science type.

What Dave did was take the NASA public domain (Shuttle Radar Topography Mission) data and turned it into contour maps. This NASA data is a grid of 'height in meters' for each 3-arc-second point across the planet (well, only as far as 60 degrees N and S, since the shuttle orbit was not polar). It's distributed in one degree 'tiles', labelled by their lower left corner for the regions we care about .. i.e. N54W001.hgt is the file covering 1 degree west, 54N through 0 degrees (E or W .. take your pick) 55N. You actually get 1201*1201 points in the file, since they measured 'fence posts not fence panels'.

The processing involves 'patching in' any known heights into regions where there is no SRTM data (the files contain 'voids', where the radar didn't get a sensible return signal). You then have to clean up some really dud points, like sea which is 25m below, or 9m above sea level, (anything between -15m and +9m gets set to zero).

The next step is to interpolate (a fancy word for 'guesstimate') the remaining voids, after which the 'cleaned up' heights can be turned into contours. The programs 'Blackart' and 'Dem2Topo' were used to do this, and Dave got a lot of support from the author of Dem2topo, who managed to make the program run 1000x faster on the Scottish Highlands areas (else we'd still be waiting).

Hardware

You need a GPS unit which can load maps and which has sufficient memory to take the file or files you are interested in. One recent example is the Garmin Legend C, which has 24Mb of memory available and can take much of Scotland's contour maps.This model also uses a USB connection which makes data transfer fast and convenient. I have experience using Garmin units and software only, presumably Magellan go their own way too in this respect.

Illustrations below show examples from both version 1.2 (L) and version 2 (R). Areas shown are approximately the same. Note that contours are more rounded, reflecting actual slopes more accurately.

Software

Mapsource is the official Garmin program for handling routes and maps etc. It's recognised as being 'clunky' and 'unforgiving', but you may get a copy when you buy a Garmin model.

To use with Mapsource you will need the .img file for the index sheet, and the .tdb file which records file data. You also need to insert a reference in the Garmin section of the windows registry. To do this a .reg file is provided. Install the files onto your hard drive, usually in the Garmin directory under contours (e.g. C:\Program Files\Garmin\contours v2). Double click on the .reg file and Mapsource should then recognise the contour maps. Load one or more into Mapsource in the usual way and you can then select a map to send to your GPS unit.

After several frustrating days trying to get Mapsource to leave its sandpit and actually do something useful I gave up and found the answer: IMG2GPS. Find it at

http://www.img2gps.co.cc/

This neat, small, and free piece of software loaded my img files in seconds with no whining, crashing, registry error message boxes or any of the mindless crud exhibited by Mapsource. It is not visual, so you have to know what area and hence file you wish loaded, but this is no big deal. Highly recommended for those who wish to retain their sanity!

Registry hacking is fraught with many dangers, and you use these files at your own risk - ensure you have all data backed up and if using Win XP make a System restore point in case everything crashes. Neither the SMC nor Dave Storey accept any responsibility for the use of this data, either with regards to your computer, GPS unit and your data, or to use on the hill. Loading these contour maps will also probably invalidate any Garmin guarantee. You have been warned.

If you would like more information on registry edits, go to http://www.keenpeople.com/index.php?option=articles&task=viewarticle&artid=4&Itemid=3 near the bottom of the page for more information.

If you want to just view the files, and don't have Mapsource (or find it a bit cumbersome, which it is) you can open the .img files with the freeware program 'GPSMAPEDIT' from www.geopainting.com. Turns out you can also edit and recompile them (using cGPSMapper, free edition), should you wish to do so. For instance you can combine several of the 1 degree squares, and use the 'trim' feature to output the region you really wanted. Dave Storey has no problem if people want to do that, although acknowledgement of the source would be nice.

A good Help Site for using the contour maps is here:
http://www.paulmac.force9.co.uk/geo/index.html

We value feedback but do not offer any support on the use of these maps.

Feedback to either us at smc@smc.org.uk, or GSV at quik.clara.co.uk - substitute the 'at' with a @

The Maps

In general the contour files are arranged in the same way as the original data, although the numbering is different (Garmin maps have to have an 8 digit number .. no 'N' 'W' etc. need apply). However for regions where there wasn't much going on, or where it made sense, some of the 1 degree squares have been combined, and we believe in at least one case 'split' to assign part to an adjacent Irish square and part to the UK.

The overview 'Contours.img' file is the index to what goes where, but here is the key to roughly which IMG file contains the original tiles. A landmark is a prominent feature within a map area - not necessarily its centre. It is listed for convenience.

Also for convenience, files have been zipped as groups into ten files for downloading. The groups are arranged by latitude and the file name is obvious, with groups starting in the south of the Uk and working north. Whichever area you are interested in trying, you must download the Essentials.exe file.

The files are listed here with their sizes to the nearest Mb. Each file is a self-extracting archive, so you can simple download and run the file and it will extract all the individual files. No software will actually be installed to your computer. Please try not to overload our server by downloading only those files you really need! As a tentative step to a visual guide, here is a map of Scotland indicating which area the numbered img files cover. The numbers incidentally indicate the Lat and Long of the bottom left corner of each 'tile'. As time allows the remainder of the UK and Eire will be added.

V2N4950.zip (5MB)

V2N51.zip (13MB)

V2N52.zip (17MB)

V2N53.zip (11MB)

V2N54.zip (14MB)

V2N55.zip (11MB)

V2N56.zip (13MB)

V2N57.zip (11MB)

V2N5758.zip (7MB)

V2Essentials.zip (0.5MB) This includes Names, Trig Points, summits & hills, Voids, Readme and several essential files.