Calibrating via MM Navigator

[mhb]

I am trying to scan in and calibrate part of a 'Cartografia Militar De Espana' 1:50000 paper map. However the Lat/Long is based on a Euro datum (presumed to be Euro 50 although this is not stated on the map).

My problem is that I have no idea how to tell the calibration window that the datum is Euro 50, rather than the default WGS84 which MM seems to assume. The obvious way would seem to have been via 'position format' from the 'Mode' menu but this does not list Euro 50 and selecting 'Other Grid' opens a Windows file locating/opening window for a purpose which I fail to understand.

Any help or advice would be much appreciated.

[mhb]

For the record, I find that there is no direct 'in program' way to input Euro 50 datum coordinates but there are websites which offer conversion to WGS84 coordinates. These converted coordinates can then be put into MM to effect calibration of the scanned map. Judging from a comparison between such a calibrated map and results from 'Google Maps' (which give coordinates based on WGS84, of course) for the same area, the coordinates seem to match pretty closely.

The 'Other' option from the MM 'Mode' option apparently affords the ability to load in 'calibration files'. However I have been unable to find out what form these should take so cannot use the facility.

[7andy]

I had the same issue with a Swiss Topo 1:25000 map. The Swiss co-ordinates are, apparently, wildly out. After I used the converter at SwissTopo, the map georeferenced to within a metre!

Very impressive...

[mhb]

That's great news as I will not be able to check my maps on the ground, so to speak, until the summer when I will visit Spain.

I have, however, had good results from scanning OS maps here, with the added advantage of scanning at 600 dpi (rather more than original MM OS maps) which enables zooming in to a much greater degree so making the PDA small screen in bright light rather less of a problem.

[7andy]

After I scanned mine in, I checked them against Google Earth. I took a Lat/Long reading from MM and input this into 'earth to see how closely they lined up. Surprisingly accurate actually.

7&Y

[inspiredron]

For a recent trip to Lanzarote I downloaded a map from the web, resized it upwards using Irfanview and then calibrated it using visual matches with Google Earth with surprisingly good results. I calibrated using around a dozen points.

We see you’re using an ad-blocker. We’re fine with that and won’t stop you visiting the site.
Have you considered making a donation towards website running costs?.
Or you could disable your ad-blocker for this site. We think you’ll find our adverts are not overbearing!