Using the free OS 10k street level maps

[Rob_Brookes]

A number of folk have asked if they can use the 1:10,000 scale 'Steet-Level' maps that are available free of charge from Ordnance Survey, in MRMap. The short answer is, Yes, you can - but.............

At the moment MRMap doesn't inherently handle these particular maps although if there are enough requests for them to be included, I'm sure Dave can fix that.

In the mean time you can use them if you manually add the necessary geo referencing information for each map tile. For the entire UK, this comes to 10,586 tiles so you might be at this for a little while. For those who haven't seen them, they look like the example below and they're actually quite good, resembling the high-end satnav maps you see in vehicle installations.



In order to make these maps available to one and all, you first have to down load them from the OS website at
https://www.ordnancesurvey.co.uk/openda ... ducts.html
These are fairly big downloads and you're on your own there. What I can do for you is having written some code to handle the conversions I can now turn the supplied Ordnance Survey geo referencing files, the xxxx.tfw 'World Files' en masse into the xxxx.mdf files needed by MRMap. I've done all 10,586 of them but can only check the ones for Cumbria which are the SD and NY folders. I haven't downloaded any others but each regional folder comes with all the referencing files for the rest of the country, which is nice.

There is a price to pay in all of this of course, you currently have three map folders:-
Maps (standard 25k)
Aerials (The Getmapping photos)
Overview (The free OS 1:250,000 scale 'route-planning maps)

You can actually put what you like in any of these folders but you have to sacrifice one of them if you want to use the 10k maps.

For those who want them, the referencing files are attached. The code I wrote to handle the conversions wasn't up to Dave's standard so if anyone finds any anomalies, please let me know and I'll correct them for you. The process used is repetative and so in theory, if it gets one right then it gets all of them right however software, expecially if I've written it, doesn't usually work that way so there might be some glitches, shouldn't be but I'm not about to say there are none.

Down load the map tiles you want to use and add them to one of your existing 'Maps' folders. It's probably easier to strip them from their 'SD', 'NY' etc folders and use just the .tif files as they have to be in the same folder as the geo referencing files.

Once you've got a folder full of map tiles, add the .mdf files from the zip file attached to this post. That's it, they're now all referenced and will load if you click the icon for that folder. To emphasise, the .mdf files from the zip file must be in the same folder as the actual map tiles so that they look like this:-

SD58se.tif
SD58se.mdf
SD58sw.tif
SD58sw.mdf
Etc, etc.

MRMap will find the files and have a look to see if there's a referencing file. In this case there is so it will use it. Any problems, let me know.

And I forgot to add, you will of course need to leave your machine on for 24 hours again so that MRMap can process the new maps. During this period, MRMap can be used as normal but scrolling the maps might be a little slow until all the maps are processed. I haven't looked to see if any of the other downloads from Ordnance Survey might be of use and certainly in the case of the Vector Tif files, they're already 1:25,000 scale and so will just work if anyone wants to use them. They don't need any additional georeferencing. If there are others that need the tfw files converting then I'm happy to do this and post them here.

The .mdf files are no longer needed. See Dave's post at the bottom of these. MRMap now handles the 1:10,000 scale maps automatically.

[David_Binks]

Well done Rob, thanks for doing this.

One thing I need to point out: MRMap is optimised for the three scale that it can handle, so if you use the "Overview" directory for very small scale maps you may see some problems, mostly with zooming out. If you zoom out a long way using the "Overview" map folder for 1:10k maps you will get problems due to the number of tiles that will be visible (1000's for the 1:10K, but only 100's for the overview maps) as you are allowed to zoom out a long way! The problem will probably start to show as tiles not loading and showing as black squares, so if this does occur you will need to close MRMap and restart to recover this.

If lots of people want the 1:10K, then I could allow the various optimisation parameters to be available in the ini file so these problems will not occur.

Dave.

[Rob_Brookes]

Dave, would ini file optimisation be preferable to another maps folder button? I suspect we might not have seen the end of free maps from OS just yet. I have the 10k maps in the 'Aerial' folder where they work OK and can actually add to the appearance of the standard 25k maps if the 'Merge' button is used. They add street names and colour to woods, & trees in general for example.

For those downloading these maps because they're not members of rescue teams and so don't have access to the OS 1:25,000 scale raster maps, the '25k Vector' maps on the OS website can be downloaded FOC but they're not 'Vector' maps which we couldn't use anyway. They're not made up of numerical line and point drawing information as a true vector map would be but are a graphical (raster) representation of what the drawn map would look like. Unfortunately their perceived usage is as a background on web pages (imaginative on someone's part) and so they have a generally 'washed out' appearance. This can be improved by batch processing them in one of the many graphics handling applications available if you wanted to.

For the benefit of those who keep asking the question, No, MRMap can't handle APRS* formatted data. However there are numerous applications that use this data format into which you can import your own maps. All the OS free maps come with either .tfw or .tab 'World File' geo-referencing information. These are simple 1k text files that can be read using Notepad or similar. The last two values in the .tfw file are the eastings and northings, usually, of the top left hand corner of the map tile so you should be able to arrive at the information needed by most APRS* applications that can handle imported maps.

If anyone wants it researched separately and the results posted up here then I'm happy to do that. The original work for all of this, over 12 years ago now, was done using APRS* on 4 metres but I'm now out of date with what's available so would need to look again.

* APRS - Amateur Packet Reporting System. Data based on the AX25 protocol which was itself based on the old Bell X25 one.

[David_Binks]

A bit old now I know, but MRMap will now handle these street maps automatically, just put them in the StreetView folder using the names as they come.
Dave.