Thursday, December 29, 2005

 

PAQ7 compression released

PAQ7 is a command line file compressor and archiver, that achieves far better compression than the standard ZIP based archivers (and in fact better than almost anything else available).

The better compression is achieved by trading memory usage and speed for compression, and the program uses a neural network to combine a number of predictor models that predict what the next bit in the file will be. Of particular interest are the predictor models that are specialized to work with tiff and jpeg files - in my tests the program achieved around about 20% compression of jpegs in the archive. Technically what it does it to partially decode the jpeg stream, back to the image coefficients, and simply apply better lossless compression to that level of data.

PAQ7, as its name suggests, is one in a long line of experimental leading edge compression programs - and this version is roughly 3 times as fast as its predecessor. The program's source code is available under the GPL, and builds for many platforms, including Windows and Liinux.

Also recently released is a beta of the closed source archiver and compressor WinRK version 3. which similarly achieves very high compression ratios whilst taking a long time to compress files. WinRK is a GUI based program, only available for Windows. It also has a special jpeg recompression algorithm.

Currently neither of these jpeg recompression modes achieves quite as high a compression ratio as Stuffit achieves, which I talked about earlier in the year.

Wednesday, December 14, 2005

 

Yahoo and Google widget APIs go head to head

Yahoo! and Google have both just released new API's for building widgets. The Google offering is new, and allows you to add the widgets to your personalized Google homepage, whereas the Yahoo! offering is at version 3 - but you need to have downloaded the Yahoo! Widget engine to run the widgets (hence they are limited to Windows and OSX).


Both types of widgets are written in Javascript, so it is fairly easy to adapt from one API to the other. At the moment the Yahoo! widget gallery has 1600 entries, whereas the brand new Google widget directory has just 5 staff written samples.


Friday, December 09, 2005

 

New Virtual Earth SDK

I've not had much time yet to investigate Virtual Earth v2, now branded as the instantly forgetable local.live.com, but I did have time to notice that all existing mashups are broken. This seems like a very silly thing to do if Microsoft actually want people to develop to their API - who will bother developing to something that will be broken at whim by Microsoft?

I also downloaded the help for the new API. This is distributed as a self extracting zip file. Why? In an age where people are understandably wary of exe files, why does Microsoft decide to distribute a help file as something that requires an extra step before it can actually be used? The help file has internal compression anyway, so the zipping up into the exe increases the size of the file, not decreases it. It's also a Windows only format (both as a .exe, and as the .chm it extracts to), yet by nature of being a web service, the mapping control is cross platform.

Update: Not only are many existing mashups using the previously published (v1) API broken, but as Microsoft's official developer site ViaVirtualEarth notes, the sample code given in the v2 SDK doesn't work either. In fact the only way Via Virtual Earth can get it's new sample to work is link to entirely different URLs for the Javascript and stylesheet files.

Saturday, December 03, 2005

 

London and the UK revealed in very high detail

The Google Earth dataset has been updated to add very high resolution (one pixel per 6 inch) aerial photographs of London in particular, but also a large number of other significant parts of the UK.

The BBS announcement lists:

London 2001,
Bedfordshire 2002,
Berkeshire-2003,
Birmingham-2001,
Bournemouth-2000,
Bournemouth-2003,
Bristol-2003,
Broadlands-2003,
Cambridge-City-2002,
Cambridgeshire-2003,
Corby-2003,
Coventry-2001,
Dudley-2001,
Exmoor-2003,
Farnborough-2004,
Gloucester-2002,
Gosport-2001,
Isle-of-Wight-2004,
Kingston-upon-Hull-2003,
Lancashire-2000,
Luton-BC-and-Airport-2003,
Manchester-2000,
Mansfield-2003,
Medway-2003,
Merseyside-2000,
Milton-Keynes-2000,
North-Lincs-2002,
Peterborough-Hampton-2002,
Poole-2000,
Portsmouth-2004,
Reigate_and_Banstead-2003,
Runnymede-and-Spelthorne-2002,
Sandwell-2001,
Sevenoaks-2001,
Solihull-2001,
South-Cambridgeshire-2003,
South-Oxfordshire-2003,
South-Yorkshire-2002,
South_Ayrshire-1999,
Southampton-2004,
Southend-2003,
Stansted-2004,
Suffolk-Coast-2000,
Surrey-1999,
Swansea-2003,
Tyne-Wear-Gateshead-2001,
Tyne-Wear-Newcastle-2001,
Tyne-Wear-North-Tyneside-2001,
Tyne-Wear-South-Tyneside-2001,
Tyne-Wear-Sunderland-2001,
West-Yorkshire-2002,
Wolverhampton-2001,
Wycombe-2003,
Wyre-Forest-2004

- Scotland (Aberdeen 2001, Craigmore 2003, Dundee 2001, Glasgow 2002,
Renfrewshire 2002)

- Northern Ireland (Northern Belfast 2001, Northern Carrickfergus
2001, North Downs 2001)

- Wales (Blaenau Gwent 2001, Bridgend 2003, Caerphilly 2001, Cardiff
2001, Merthyr Tydfil-2001, Newport 2001, Rhondda Cynon Taff 2001,
Torfaen 2001, Vale of Glamorgan 2001)

This imagery is provided by The GeoInformation Group, who also power the Cities Revealed website, where you can buy printouts of the data.

There are also smaller updates to other international data:

Updated/improved Digital Globe .7m data
---------------------------------------
- Alexandria, Egypt
- Asuncion, Paraguay
- Bamako, Mali
- Bangalore, India
- Cairo, Egypt
- Hyderbad, India
- Kano, Nigeria
- La Paz, Bolivia
- Mexico City, Mexico
- Montevideo, Uruguay
- Omaha, Nebraska
- Provo, Utah
- Pune, India
- Quito, Ecuador
- Sydney, Australia

NYGIS (updated imagery)
- Albany, NY
- Columbia, NY

USGS
- Las Vegas, Nevada
- Springfield, Massachusetts
- Mt. Helena, Montana
- Nashville, TN

Other
- fixed mask for Galapagos Islands
- Digital Globe imagery of Pakistan earthquake area
- Nanaimo, Canada
- NW Arkansas

Friday, December 02, 2005

 

Google Desktop plugin to search Google Earth files

Google have released a plugin for Google Desktop which allows it to index and hence search Google Earth data files.

This was announced via a Keyhole bbs entry. After installing the plugin, any KML or KMZ files created or updated will be indexed - though as the readme states, existing files of these type will not be automatically crawled (though you can force them to be found by adding their location to the directories to be explicitly crawled).

It's author is Davis Eustis who appears to be a new hire - at least he hasn't made any previous posts to the Google Earth BBS.