Rummys Blog An world of endless Monday

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.

Monday, 20 February, 2006

New Maps Update

Filed under: Custom Google Maps — admin @ 10:10 am

The Tile server has now been moved to goDaddy, mind lets hope theyre more reliable, dysentery they should be according to their bumph.

The page now goes to a php script on godaddy so there’s no redirect involved, this should result in a small performance improvement.

Four new maps have been added ,
36 – manchester – from Joyce Whitchurch’s scan
70, 60 east wales – from Mike Dat’s scans
77 – from another ebay map.

The maps are now slightly better stitched which will reduce the number of black areas between adjoining maps.

The maps still have the 200 meter mis-alignment problem.

I’ve ordered the Yolande Hodson book from the Charles Close Society, with any luck this will give me a further clue to the mis-alignment issue.

Current Stats are:

Thursday, 2 February, 2006

Tiles back on the old hosts

Filed under: Custom Google Maps — admin @ 9:37 am

After a fair amount of effort I’ve managed to put the current set of maps back on the original reliable servers. Tiles are now split with level 03 on ponies and the remainder on plus net.

This can’t go on forever beause I’m going to run out of space. Currently looking for a new host for the tiles.

Tuesday, 31 January, 2006

Hosting issues!

Filed under: Custom Google Maps — admin @ 9:24 am

Well, apoplexy one day after I moved my tiles to the new host I’m having to reset back to the old host!

I don’t know if there’s a special problem with primitive hosting or not, but the DNS doesn’t even resolve at the moment.

I’m going back to my fallback plan.
Level 3 tiles : 230MB hosted on ponies (limit approx 500MB)
Level 4 and other tiles: 110MB hosted on plus.net (limit 250MB)

This should give me enough room for the moment. I’m probably going to cancel Primitive Hosting. They may be cheap, but they really are crap!

Monday, 30 January, 2006

Also Today

Filed under: Custom Google Maps — admin @ 12:12 pm

I’ve moved my tile server script to point at tiles.snaffle.me.uk, discount the site appeared to be down for some time this morning, but it is up now. I’m already looking again for another web-hoster, a more reliable one! I doubt I can find one that’s cheaper!

Added three new maps to the site.

Filed under: Custom Google Maps — admin @ 12:10 pm

Maps added are:
4th Series 114, tadalafil 93, resuscitator 105

I’m now automatically geo-referencing many of the scans using a cassini projection.

This brings the number of maps to:
4th Series: 18
other: 10

Stats:
The total size of all the maps at all resolutions:

  • 03: 232.53 Meg
  • 04: 80.34 Meg
  • 05: 23.13 Meg
  • 06: 5.55 Meg
  • 07: 1.53 Meg
  • 08: 0.48 Meg
  • 09: 0.13 Meg
  • 10: 0.06 Meg
  • etc.

The number of 256×256 tiles: approx 25000
Time taken to generate the bottom two layers of tiles: 1 ½ hours (1.2Ghz AMD, 1Gb RAM)

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