[closed] Precise Control Over Map Overlay Implementation + QCT3 Maps

[Yemble]

The GBOS Landranger & Explorer maps are probably amongst the best maps on the planet. The OS also produce a pretty good 1:250K road atlas that is much more informative than the rather bland base map currently packaged with the GBOS maps in AQ.

Both Memory-Map and ViewRanger offer this road atlas as a free download and I also happen to have an older MM QCT version of this map. When overlayed on top of the GBOS maps, the road atlas effectively replaces the base map at most scales (which is a good thing), but also replaces two out of the three scales jumps of the 1:50K Landranger map (which is a bad thing).

Is there any way to control the points at which an overlay is and is not applied? I would like the road atlas to overlay onto (ie. replace) the base map ONLY.

Also, I believe (although I could be wrong) that although the latest MM road atlas is in QCT3 format, it is in an unencrypted state, unlike their premium paid-for maps. I think that this has been requested before, but is there any chance of supporting unencrypted QCT3 maps in AQ? If so, I could easily keep my road atlas up to date.

[Psyberia-Support]

Hi and thanks for the information, I didn't knew about that. I'll have a look at the free data offered by the OSGB, I already came across OpenData and I found very interesting thing, but I didn't had time to go further and didn't noticed the 1:250K map...

Concerning your question about the layer control, you cannot do it with any maps.
Here are the only possible ways to achieve what you want to do:
- If you are only dealing with online (stored) maps, then you can (at least I could) create a new XML map definition and choose exactly what levels of each map to use at any zoom level;
- If you are using MOBAC, then you can mix any map sources for any levels in the AQM format.
Unfortunately, right now nothing is possible with QCT maps. The only thing I see is to use the new opacity controls to hide the road atlas when zooming in.
Maybe something automated could be added (like a rule for a given map "set opacity=0% for zoom>xxx), but I won't have time to do it quite soon...

Concerning the QC3 format, I already tried to support it (see this discussion), without success. I hope to find time one day to work again on it, but right now there is so much asked features waiting...

Best regards

[Yemble]

OK, that's understood. I think that this idea goes in category of "nice to have" but not particularly urgent. However, I would like to know a little more about how community map packages are put together and where they come from.

[Yemble]

Rather than worrying about how to convert MM QC3 maps, I thought I'd check out the OS website first. It turns out that the 1:250K road atlas is freely downloadable direct from there, along with some other useful stuff: https://www.ordnancesurvey.co.uk/openda ... ducts.html

The maps download in "World File" format, as .TIF, .TFW and .TAB, which can then be converted with MAPC2MAPC directly to AQ format. I particularly like the MiniScale map of the UK, which when converted for zoom scales 7 to 9, overlays nicely onto the OSGB community map, effectively replacing the bland default base map. At zoom scale 10, the map flips seamlessly to 1:50K.

The 1:250K road atlas is a bit more of a challenge as it is delivered as 56 tiles rather than a single map. I don't know if AQ can work with a tiled off-line map, if so I don't know how. So I believe that the map tiles need to be merged prior to conversion to AQ. Whether, or not, MAPC2MAPC can merge maps in batch remains to be seen - I hope so, since doing it manually would be a real pain!

Would I be correct in thinking that the "+" button in AQ zooms in steps of two? From experimentation with one of the road atlas tiles, it looks like best quality is reached at zoom level 11, which is mid-way between the zooms steps of AQ. This means that the switch between 1:250K and 1:50K does not occur at the ideal point - so this atlas may not be an ideal overlay for the OSGB community map after all.

I'm still experimenting...