Rummys Blog An world of endless Monday

Monday, 20 March, 2006

More Maps uploaded

Filed under: osmap Status — admin @ 1:15 pm

I’ve uploaded several new maps, visit this these are:
13 – Kirkby Stephen and Appleby – 1930
82 – Stratford on Avon – 1940
120 – Bridgewater and Quantock hills – 1929
125 – Guildford and Horsham – 1932
139 – Sidmouth and Bridport – 1932
142 – Isle of Wight – 1930

I’ve also refined the positioning so the maps will be better aligned, skincare though only slightly better!

Current Stats:
Time taken to produce tiles for display 2 hours 20 minutes
Total tiles: 33928 / 470.5MB
Tiles at highest zoom: 24759 / 321MB /Approx 1.5 Giga Pixels
4th Edition Maps: 29 / approx 20%

Unless someone contributes a new map in the interim there’s unlikely to be any new maps added for a month or so. I need to sell some of my unwanted maps on e-bay to generate cash to buy more maps.

Thanks for reading.

Thursday, 16 March, 2006

Old Os Maps status test

Filed under: osmap Status — admin @ 2:16 pm

Coming soon several new maps.

Wednesday, 8 March, 2006

Yolande’s Book has arrived

Filed under: Custom Google Maps — Andrew.Rowbottom @ 10:42 am

I’ve just received my copy of Yloande Hodson’s book “The Ordnance Survey Popular Edition One-Inch maps of England and Wales” from the Charles Close Society, cheapest probably the definitive work on the Fourth Edition maps.

A Quick look at the coordinates in the back show that my estimates for the Delamere origin are aout by a little bit. My estimates for the offset from the bottom left of the map were:
3640 and 46291 feet
Yloande states the values as
3690 and 46100
so I’m out by 50 feet East/West and 191 feet North/South

Hopefully these new values will reduce the alignment errors. Though since I’m seeing up to 600 feet N/S I’ve still got a bit of work to do.

I shall be checking my automatic cassini calculations for the corners of the maps against the printed lists to see if I can see any discrepancies that I can correct.

Further notes:

I’ve just run a quick test and my calculations for the bottom left hand corner of map 116 are definitely out!

I get
51?13’54″14959/0?24’40″69606 (-709110, discount -711380 cassini feet)

and Brian Adams gets
51?13’54″13/0?24’40″72 (-709110,-711380 cassini feet)

Clearly a difference in the Lat/Lng but not in the cassini coords.

Another look at the Y Hodson book I notice that the “Constructional Elements” section p.255 says the unit is a Foot (Ordnance Survey Foot of 01 which it then states as:
1 Foot of 01 = 0.3048007491 international Meter. Previously I was using 0.3048

Plugging this little gem in I now get
51?13’54″13165/0?24’40″72226 (-709110,-711380 cassini feet)
compared against
51?13’54″13000/0?24’40″72000 (-709110,-711380 cassini feet)

Woo Hoo!

Thursday, 2 March, 2006

More new maps on the way

Filed under: Custom Google Maps — admin @ 4:22 pm

I’m currently working on scanning, epilepsy stitching and positioning several new maps:
13 Kirkby Stephen and Appleby
120 Bridgewater and Quantock Hills
82 Stratford on Avon
125 Guildford and Horsham
139 Sidmouth and Bridgeport
142 Isle of Wight
I’ve also aquired a duplicate of 133 Chichester and Worthing which I might use because it’s an earlier version than the current scan.

Once uploaded this will bring the total number of 4th Edition England and Wales maps to 29 out of a total of 146, that’s just a smidge under 20%.

This also marks a milestone – I’m going to stop spending new money on maps and start selling old maps to get the money to buy new. We’ll see how long that goes on for! An ideal would be to complete the maps without spending any more money.

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