DVD Backup

Saturday, 29 September, 2012

Every so often I want to backup a DVD or portion of a DVD from a disc and need a simple solution to do it (ideally open source!). So it’s worth recapping the two stages needed:

1. Copy the files from the disc: they are encrypted so you need software that will decrypt them (and sometimes merge the multiple VOBs to a single file). You can do this with DVDShrink which helpfully runs portable. If you select the reauthor option then you can clip on the section you want to grab. If your disc is partially damaged this won’t work so another option is to install DVD43 which actually intercepts Windows file calls to the DVD player and then decrypts the files on the fly which means your software in step 2 should work

2. Author the files to your desired format. DVDShrink can compress the files for you or you can use something like MPEG Stream Clip to do the same thing. This would also allow you to demux if you just wanted the audio or video.

East Midlands Trains Wifi

Friday, 28 September, 2012

The good people at East Midlands Trains run an occasionally satisfactory service that I sometimes frequent. They offer free wifi which really must be a relatively “no cost” service for them to provide. For First Class passengers this is free probably because it provides some differentiation and excuse to charge the higher price tickets. Anyway (and thanks son!) their trains have mixed first/standard class seats which means, if you share the coach, you share the wifi. It works well, varies between fast and slow broadband speeds and operates in tunnels. All-in-all better than relying on mobile. It’d be interesting to know what the contention ratio is like and, in fact, what connection they use out on to the wired network. Useful tip of the week!

Open Dyslexic

Thursday, 27 September, 2012

Nice article at the BBC on Open Dyslexic….openly accessible fonts (and associated software) to make screen reading easier for dyslexics. Very good.

DVB transmission to archived XVID

Tuesday, 25 September, 2012

I had recorded a short clip off the TV using my Humax box - once your Hummy is connected to a network, with UPnP switched on, it’s easy enough to copy standard definition recordings straight off the box on to your PC (see previous post). These come off as .TS files, but this time I had a load of aggro trying to archive them to XVID. Not sure why and VLC wasn’t playing the file either. Anyway, after a fair bit of head scratching this workflow seems pretty good:

1. Split (demux) the .TS in to constituent audio and video streams using ProjectX
2. Combine (mux) the streams in to an .MPG (using .MP2); use MPEGStreamClip
3. Transcode the file using Mencoder
4. Play using SM Player Portable

Large FAT32 hard disk drives?

Monday, 24 September, 2012

If you order an external hard disk drive (HDD) chances are it’ll come formatted using NTFS. That makes sense as it’s an up-to-date system, however it isn’t so easy to use when you want to switch between different OSs. For those that want to use FAT32, which is well supported, then they hit a wall in Windows as formatting only supports up to 30Gb. Well that’s an artificially imposed limit by Microsoft. Simply use FAT32 Format and it’ll do the job.

Nice

New term, new students and…. new digs

Saturday, 22 September, 2012

Yes, that time has come, the first offspring departed for University and a new educational frontier (at Keele) awaits him. Across the country students are turning up with car loads ready to embark on a new life in charge of their own living. And digs are an inevitable part of that, be they university based or private. As a regular academic conference goer I get so see a variety of university accommodation (Swansea, Loughborough, Cork, Royal Holloway etc) and I can honestly say that Keele ranks at the bottom of this….by some margin.

See the university page for Lindsay Hall and compare it to the photos I took today….. very old furniture, a prison bed, plastic curtains and a heavily stained carpet with holes cut in it (presumably for long gone furniture). Its a 1960s build (not uncommon in the UK), however it looks like it was last decorated in the 1960s. Its cheap and its not really that cheerful. OK, its part of undergraduate living and with a few posters on the wall and the heating on and a few beers inside it doesn’t feel quite so bad (just as well I didn’t take any pictures of the showers).

But really, Keele, is this the best you can do for students being charged 9000 to study with you?? We expect all universities to make the grade in the UK, so quality of living is becoming a differentiator. To add insult to injury the radiator leaked, the electricity didn’t work, there was no phone and the woefully low strength aerial meant no digital TV (with the alternative of internet based Freeview over a bandwidth throttled connection).

It’s perhaps unfair to single out Keele - the digs we use in Swansea for fieldwork aren’t great and there is much variability across all campuses, with most having new builds with very nice accommodation. But there is no excuse for leaving living accommodation in this state - the world has moved on.

Google Cloud access to Landsat archive

Saturday, 22 September, 2012

This is a nice catch on accessing the Landsat archive. As with all things Landsat, its organised by path/row of individual scenes. Use the NASA convertor to work out which path/row you are interested in. You’ll then see a list of scenes with numbers such as this: LE70592202007107EDC00. The file contains ALL the bands in the image but encoded in name is the sensor (LE7 or Lndsat 7), path/row (059/220), scene date (2007107; think there must be a digit missing here or its an abbreviation) and source (EDC or Eros Data Centre).

Once you’ve got the file use 7zip or similar to decompress/unarchive. This will give you a series of files (band designations here) such as:

L71059220_22020070417_B10.TIF
L71059220_22020070417_B20.TIF
L71059220_22020070417_B30.TIF
L71059220_22020070417_B40.TIF
L71059220_22020070417_B50.TIF
L71059220_22020070417_B61.TIF
L71059220_22020070417_MTL.TXT
L71059220_22020070417_B62.TIF
L71059220_22020070417_B70.TIF
L71059220_22020070417_B80.TIF

These are bands 1-5, the two thermal bands (low gain and high gain) and band 7. Band 8 is the higher resolution (15m) panchromatic (read: B&W) band. If you are using these in a remote sensing package such as image you’ll need to layer stack them.

Go grab as its quick and easy once you know what you’re looking for.

Android App Update

Friday, 21 September, 2012

String of recent app updates that are worth a mention:

Mapdroyd: my favourite offine maps. Yes, offline, on your device, using full street level data from OSM. They’ve now moved to version two, a complete re-write using a new data format that, amongst other things, allows street/place searches. Better than before - a must have.

k9 Email: fantastic email client for those in the know. Not on Play, but Google code. Very regularly updated and now with a swish new interface. Nothing else worth a look.

TouchPal: as a longtime Swype user I have been disappointed at the bloat (17mb) and, more recently, the extremely laggy keyboard. It has gone from great to broken. There are now a few alternatives around and TouchPal is particularly good. Lightweight (4mb), lightning fast and flexible.

Perfect KAP camera??

Thursday, 20 September, 2012

Well, Nikon made a big splash by announcing the D600, the first consumer level full-frame (FX) DSLR (and plenty of reviews). Full frame is the key point and as cameradebate.com note, you get a bigger sensor which has four benefits:

No cropping of the image when using a 35mm compatible lens
Achieve shallower depth of field
Higher sensitivity and less noise (aka better high ISO performance)
Higher Dynamic range
Bigger and brighter optical viewfinder

The key point is that a full 35mm sensor is fitted in the lightweight magnesium alloy/polycarbonate body, almost the same as the D7000. This reduces the size and weight; its 760g as opposed to the 1000g of the D700.

Is this the perfect KAP camera? Well maybe - it has the high geometric fidelity and ability to use high quality lenses that we found when shooting with the D70. More importantly it has much greater sensitivity meaning that you can shoot at fast shutter speeds and high ISOs to obtain much sharper images, crucial for high quality photogrammetry. The ability to create high accuracy DEMs is significantly enhanced and the 24 megapixel resolution places it in a league of its own. Next step is to see if Nikon are willing to let me hang one underneath a kite!!

KAP Camera Coverage

Tuesday, 18 September, 2012

When mission planning for a Kite Aerial Photo (KAP) survey it’s useful to know the approximate coverage of each photo and pixel size. These parameters are basically reliant upon sensor resolution, flying height and lens type or more specifically:

-sensor size (width/height in millimetres)
-sensor size (width/height in pixels)
-lens focal length
-flying height

When I started my KAP work back in 2005 I wanted to calculate these automatically and Clive Boardman at Photarc Surveys kindly sent me an spreadsheet he used for mission planning. So I thought I would make it available as it’s incredibly useful. For my use I enter the the flying height which lets me see the image dimensions and pixel size. Enjoy!