Big TIFF is out.

Sunday, 28 October, 2007

BigTIFF appears to be coming close to an official release. TIFF has been a popular format within geospatial circles for a while because its an open format (although Adobe owns the specification) and there is the open source libtiff library used for reading/writing TIFFs. It’s also incredibly extensible and has proved the test of time when it comes to image processing. . The problem for the geospatial industry?? File size is currently restricted to 4Gb. This might have seemed gargantuan 5 years ago but there are now many libraries of images which are easily bigger than this. So the BigTIFF project was formed which garnered industry financing to support the extension of libtiff to break the 4Gb barrier. ESRI and Leica are amongst the industry support and its a cheap way for them to get an extended TIFF format.

So where can you use BigTIFF? Well as far as I’m aware Ossim is the first to support it (at least in the geospatial arena). So if you haven’t tried Ossim, now’s a good time.

Concatenating in Windows

Wednesday, 3 October, 2007

I was recently sent some LiDAR data x,y,z triples (i.e. x coordinate, y coordinate and elevation); actually, it also had intensity so quadruples I guess. Anyway, the data were extracted for a 1km2 area from multiple flight lines which meant I had multiple x,y,z values. Before importing these as a LiDAR LAS file I wanted to concatenate them. Easy to do in Linux but I couldn’t remember how to do it in Windows. A quick Google later led me to this useful article over at Lockergnome. And for those too lazy to click, this for loop will do the work for you:

for %f in (*.log) do type “%f” » aggregate.txt

IGS British Branch Meeting

Monday, 24 September, 2007

I attended the International Glaciological Society’s British Branch meeting a couple of weeks ago at the School of Geosciences in Edinburgh. As an aside, living close to Luton airport, it is quite convenient to cycle to the airport and fly up. It actually took me longer to get the bus in to the city centre! And the web check in at Luton really is very good. What it did bring home to me, is that, whereas in the past Scottish universities were marginalised by their relative “remoteness”, this remoteness has now shifted to universities in northern England such as Newcastle, Durham and York. It took 4 hours to get to Durham, compared to 2 hours to Edinburgh.

This is my second British Branch meeting and it was again and mellow affair with plenty of post-graduate presentations. These are always very good to see; not only to you get a feeling for where “current” research is going, but it providesd a great forum for them to “practise”. Long may this tradition continue. Most of the Glaciology centres had some form of presence (Aberystwyth, Bristol, Edinburgh, Queen Mary, Swansea, Scott Polar, BAS), although Durham, Leeds and Sheffield were notable for their absence, so it was a well represented meeting. Being interested in the cross-over between glaciology, remote sensing, GIS and “terrain”, Tavi Murray’s talk on volume changes of glaciers on Spitsbergen was of particular interest. NERC ARSF have had a couple of summer campaigns collecting, amongst other things, LiDAR. This project formed part of a larger NERC project and developed some long baseline GPS to enable the economic collection of data. The LiDAR were then used alongside the Norwegian historic archive of airborne survey imagery. Whilst the imagery had been flown with appropriate stereoscopic overlaps, it had never been processed. The advent of digital photogrammetry made this (economic) possibility more likely, however GCPs for rectification were still required. And this is where the LiDAR came in; as the LiDAR were accurately georeferenced using DGPS and onboard INS, the terrain data was accurately positioned. The intensity data could then be used to provide GCPs for the digital photogrammetry and then generate DEMs using this archive data. To the project’s surprise, there was sufficient contrast on the glaciers to allow the extraction of terrain elevation and then quantify volume changes of ice for a number glaciers. All in all, a very neat integration of technology and multi-epoch data.

DEMs, castle coffee and dodgy wifi

Saturday, 22 September, 2007

I’ve recently returned from a trip to the Geography Department at the University of Durham where I gave two research seminars on some of my close-range remote sensing and DEM visualisation work. There is a group that is particularly interested in DEM visulisation for landform mapping and I was helping them getting going on this. Durham is a very interesting place to visit, with quaint cobbled streets, a cathedral and a castle. The castle is actually part of the university, which is nominally split in to colleges in a manner similar to Oxbridge. If you are lucky enough to be part of Castle College then you can get lodgings in the castle and, as a member of staff, go to the Senior Common Room for coffee. All rather reminiscent of days gone by (and the coffee is OK).

Which brings me to the final part of my trilogy, the dodgy wifi on the GNER train. I guess I should be impressed that GNER actually have this installed and I should say that it does work. At £3 for 30 minutes it’s not desparately expensive, although I gather from later this year it will actually be free. Anyway, getting connected is easy, but the service is slow. Downloading a 30Kb email takes upto 10 seconds, which is painfull! You don’t want to be downloading 5Mb email attachments. The service also had the habit of dropping out, particularly in stations; I’m not sure exactly how the service is run, but to be honest it’s borderline as to whether it’s commercially chargeable.

Latex and change tracking

Wednesday, 19 September, 2007

If you’ve read any of my blog entries over the last year, then you will realise that I’m a regular LaTeX user, primarily for typesetting at the Journal of Maps. Until recently I had never used LaTeX for writing a research article for submission to a journal. And my initial experiences are that I won’t repeat it!! Much of my academic writing with co-authors is performed remotely. It is therefore essential, when sending a manuscript back, to keep versions and identify where any changes have been made. MS Office (and Open Office for that matter) both have change tracking and it is a simple matter to work through the changes, accepting or rejecting them. LaTeX is a typesetting system and, as far as I’m aware, is not designed for versioning. Thats not to say it isn’t possible with PDFs (and I would be interested to hear of any LaTeX packages that might help this process) as Adobe Acrobat Pro has long supported annotating PDFs. However PDFs are not the source programme and you then need to reintegrate these changes in to the original file. It’s fine for sending proofs to authors, but not good when writing a paper. This whole process was brought home when a reviewer for one paper I submitted noted that the paper felt rushed and slightly disjointed. This wasn’t intentional but, having looked back at the paper, was a result of “round-tripping” the article using LaTeX. I’d be interested to hear if anyone else has experiences along these lines.

JPEG2000 Viewer

Friday, 7 September, 2007

JPEG2000 is rapidly becoming one of the most popular image formats due to its high compression, lossless/lossy format and open specification. NASA use it for distributing HiRISE images, whilst I recently downloaded some photogrammetrically scanned air photos from NERC in JP2. Whilst quite alot of packages now support JP2 (both remote sensing such as Imagine and graphics such as PhotoShop), they can be painfully slow. Thankfully IAS Viewer is a free Java applet that can view both on and offline imagery VERY quickly. Well worth using if you need to browse imagery.

And if you really are wedded to Photoshop (or other graphics package) then try the j2k plugin. It’s also pretty fast and works well; in Paint Shop Pro it loaded a JP2 image that the native importer wouldn’t.

In a galaxy far far away….

Friday, 7 September, 2007

I was speaking at the Society of Cartographers - 43rd Annual Summer School this week (gentle introduction to spaceborne DEMs) and whilst only there for the day, a thoroughly relaxed and pleasant affair it was too.

The speaker after me was Daniel Thomas from the Institute of Cosmology and Gravitation at Portsmouth. He gave an excellent introduction to astronomy and how he is involved in the massive Sloan Digital Sky Survey to map more than a quarter of the entire sky using a 2.5m telescope and 120MP digital camera. As you can imagine, it generates quite a bit of data!! Anyway, as part of the project the team want to classify the 1 million or so galaxies that will be imaged. Computers are not particularly good at this type of classification (spirals, ellipses, edges, mergers and unknowns!) so the group has set up Galaxy Zoo, a public website that allows anyone to classify galaxies for them. A brief introduction allows you to see examples of the types of things they want to classify. This is followed by a brief test to make sure you’ve understood, then away you go. Well worth a try!

Castle Rising Castle… and tearooms

Friday, 31 August, 2007

Whilst on holiday in Norfolk over the summer we stopped at Castle Rising Castle. Whilst not belonging to English Heritage its preservation has been, at least partly, sponsored by them, so its on the “East of England” trail. And a mighty fine castle it is. According to EH:

“One of the largest, bestpreserved and most lavishly decorated keeps in England, surrounded by 20 acres of mighty earthworks. Begun in 1138 by William d’Albini for his new wife, the widow of Henry I, in the 14th century it became the luxurious exile-place of Queen Isabella, widow (and alleged murderess) of Edward II.”

So there you have it. It’s fun to look around, with corridors crudely hacked through the original 2m thick outer walls; done after the collapse of the main hall to allow access to rear upper rooms. The outer earth works provide good views and plenty of areas to wander around, including the original 13th century church which was probably torn down to make way for the castle.

Of course this is less important than the hugely impressive tea rooms in the village of Castle Rising. These are attached to the post office and are quaint and traditional. A definite stop for a freshly made cup of filter coffee or tea, along with a home made cake. Highly recommended!!

OS Benchmarks

Tuesday, 28 August, 2007

The Ordnance Survey have always maintained the trig point and benchmark network for those carrying out traditional ground surveys (leveling and or detail survey). In the past, if you wanted access to the precise co-ordinates of these locations you needed to purchase. With the advent of OS’s use of GPS and active/passive differential GPS network, trig points/benchmarks are either disused or dismantled. Whilst many liked the old survey network, it was expensive to maintain and so something had to give. However the good news is that all the (unmaintained) data is now free to use. Just go to the OS Benchmarks & Trig Archive and browse to your hearts content!

Converting Word 2007 Files

Saturday, 25 August, 2007

Now that Office 2007 is fully upon us, expect to be receiving the DOCX (and equivalent PPTX and XLSX) files from colleagues. These are the new OpenXML file format. And it really is just a plain text XML document in a ZIP wrapper. However I have an old Office 97 installation (meeting all my office needs) and have now converted over to Open Office 2 (which uses its own ODF, Open Document Format, and can read/write DOC files) which currently does not import DOCX (or derivatives). Plenty of people are working on converters or online services, but for the time being support is limited. That said, Novell Open Office does have an importer and this will apparently be fed in to the Open Office development at a later stage. For the time being the closest you can get to a DOCX/ODF converter is using the OpenXML/ODF Translator. It’s actually an MS Office plug-in to allow export, but there is a command line version which does the conversion as well. There are plenty of things it doesn’t support, but for simple documents it’s more than sufficient.

Creating ISOs

Friday, 24 August, 2007

One of the nice things in virtual machines is that you can mount real, or fake, CDs on to the VM. So if you load a CD in to your own system, the VM can access it. Likewise, if you “rip” a CD to an ISO image, you can also mount this. In fact this is the best way to install a Linux OS in to a VM; just download the xubuntu or Fedora ISO image and let things roll.

Virtual Box also has extensions which let you share local folders and so access files on your own system, however it is a bit more fiddly to setup under Linux and doesn’t support all distributions. The “quick and dirty” fix is to actually turn whatever files your want to transfer in to an ISO and mount that as a CD.

Now there are plenty of commercial applications that can do this, but that isn’t good enough. I wanted a GUI based, open source, solution that can run from a USB stick. And I found it in the form of DoISO which is an open source GUI frontend for the opensource command line mkisofs. And it just works.

Virtual Box

Thursday, 23 August, 2007

Well the world of virtualisation doesn’t stay still for long and I have now switched over to Virtual Box. Whilst not open source, the main product is free to use and is lighter and fast than Virtual Server (it also runs on Linux). More importantly, it runs both xubuntu and Fedora Core without any hitches at all. I’m using the former for playing around with GRASS, whilst the latter has been necessitated by using Pulsar for some radar image processing. Virtual Box is very easy to use which is nice. However, the more memory the better and if you have less than 500Mb things will be much slower.

Barratts Shoes and data collection

Tuesday, 21 August, 2007

I was shopping in Barratts shoes recently and paid with my chip and pin card. Interestingly, in this age where everyone is paranoid about card skimming, the sales assistant asked to swipe the card on the POS to complete the transaction. I can only assume that Barratts have installed the new chip and pin system, but their legacy tills still require a card swipe to complete a transaction. This is really very poor and does nothing to assuage customer worries. Of course, the best course of action is to vote with your feet and purchase elsewhere.

FlashEarth

Thursday, 9 August, 2007

I blogged back in May about Flash Virtual Earth which introduced a Flash platform for viewing virtual earth imagery. Well another product, Flash Earth is now available. And this is quite simply excellent. It provides a fully functional virtual earth, allowing you to select between different vendors (Google, Ask, Yahoo etc) to view imagery available. Its minimalist, simple and a pleasure to use. Definitely worth a visit.

…. and Whipsnade respond!

Monday, 6 August, 2007
The board of Directors are looking into a possibility of removing all but disabled badge holder cars from the Zoo but first there has to be a suitable alternative transport system in place. They are still in the planning stages so watch this space for further developments. I think also the problems with bikes were that not everyone stayed on the roads and tracks provided. As they are very quiet when being ridden this is another reason for not allowing them as they can creep up on pedestrians. The wearing of seat belts is not enforced as it’s not a public highway and the speed limit should be only 10mph. Whilst most people do stick to this limit I know there are others who do not.

Whipsnade Zoo

Monday, 6 August, 2007

I was visiting Whipsnade Zoo on the weekend. It’s a fun place to take kids, there’s lots to do and it helps support their wide ranging conservation programme. If you look at the imagery at Live Maps you can see an extensive network of internal roads at the park. You have to pay to take your car in, but it’s very popular in summer. Out of interest I contacted the Park to see if bikes were allowed entry (because I hadn’t seen any). I received the following reply from them:

No bikes are allowed in the Zoo due to Health & Safety implications.



This really did make me laugh, so I replied:

It’s somewhat disappointing that bikes are not allowed in, as the park has the potential to offer an excellent environment for pedestrians and cyclists. I would have thought cars posed a much greater threat to safety, noting the speeds some drivers go at, complete lack of use of seatbelts by many and the absence of footpaths in parts of the park. I do appreciate that it’s an important revenue stream for the park though.



Money rules, even in conservation. Is there anywhere we can actually get the car away from?

Dunstable Downs

Saturday, 28 July, 2007

I’ve been carrying out the further testing to the kite rig at Dunstable Downs (Note: whilst Mastermap might be up-to-date, the Landranger maps displayed at Steremap most certainly aren’t!). This offers fantastic views out over the Vale of Aylesbury, is wonderfully windy and hosts the internationally famous Dunstable Kite Festival (which incidentally is TOMORROW). It’s well worth a visit and now has the new Chiltern Gateway visitor centre. Designed to be eco-friendly and blend in to the landscape, it offers fantastic views out across the Vale and sports a reasonable cafe/restaurant.

Open Office Footers

Monday, 23 July, 2007

I’ve finally taken the plunge and am in the process of fully switching over to Open Office. I’ve been wanting to do this for a while, partly to move over to open source software and partly because of Portable Open Office.I had tried importing a few MS Word documents and whilst the text comes through OK, it is a little hit and miss with the layout. Anyway I took the time to actually convert some of my documents and all in all I like Open Office. It is moderately intuitive (and let’s face it, most “office” suites are largely similar in use), responsive and easy to use.

Inevitably there are many smaller differences between Open Office and MS Office. One of the problems I hit in Writer was making headers/footers different on the front page of a document. In MS Word there is a tick box when setting up the page that determines if the front page should be different. Not so in Open Office and it took a little while to find out the solution, although what it shows is that the design of Open Office is more natural and elegant than Word, not being hindered by a long culture of “bolting on” new functionality. In essence, anything to do with formatting comes under styles and isn’t deferred to a tick box on a setup page. Thus going in to “Styles and Formatting” (F11) allows you to change the footnote style on the first page. It’s a much better way of designing a document; just have to “unlearn” those MS Word “skills”!!

Continuous Rotation Servos

Friday, 20 July, 2007

The rig designs I have used for flying my cameras (from kites), all use model aircraft servos (e.g. Hitec, Futaba) to drive the rotation (horizontally) of the vertically pointing camera. For photogrammetric applications, vertical photos are the only ones worth taking and therefore the vertical axis is the only one about which we need to move the camera.

This creates a problem because the servos are designed for model aircraft which require movement of up to ~90 degrees for controls such as the rudder and flaps. With rotation around the vertical axis, we ideally want continuous 360 degree rotation. So what do we do?? Well the e-magazine KAPER lists six different ways of achieving full 360 degree rotation. These employ both external modifications (gearing) and internal modifications (extra electrics). Probably the simplest, and most effective, modification is method 4 which involves opening up the servo and cutting away the bump stops and grinding off the top of the final drive gear (ideally using a Dremel).

The first rig we built uses this method, unfortunately minor fluctations in the RC transmitter means that the servo occasionally stutters or will rotate (“creep”) ever so slowly when its meant to be in a neutral position. James Gentles has produced a little bit of kit which solves this problem (and is sold at Brooxes and KAPShop). The digital Futaba RC controller I use allows micro-adjustments to the controls which actually stops creep entirely, so I didn’t need this solution.

However next on the shopping list is the Hitec HSR-1422CR which purports to allow continuous rotation out-of-the-box. It’s on order so it’ll be interesting to see if this solves the problem

Fisheye Panoramas Continued

Thursday, 19 July, 2007

Pano1Well it’s been a month since my last blog on creating panoramas from fisheye lenses. I had said I would come back to using Hugin to create panoramas, it’s just taken longer than I thought!

Hugin has a set of tabs across the top for working with the current image. Many of the tabs we don’t need to use because we are not stitching photos together. When loading a fisheye image, much of the lens information is automatically entered straight from the EXIF data. So, in summary, load your image (Assistant tab) and apply the following settings:

Assistant: set “Lens Type” to Circular Fisheye
Images: set Yaw-90, Pitch-90, Roll-0
Camera and Lens: set “Lens Type” to Circular Fisheye and “Degrees of View” to 180
Crop: you need to draw a circular mask around the part of the circular photo (i.e. exclude the black surrounding frame). If you uncheck “Always centre” then you will be able to fine tine the position of the mask
Stitcher: set “Projection” to equirectangular, “Field of View” to 360 (horizontal) and 180 (vertical), select an appropriate image size and make sure the “Stich Engine” is Nona.
Hit the “Stitch Now” Button

The original image (of Carlos!) is above and the unstitched version below. I’ll have some kite shots next week.

Pano2