The Guardian: Data Visualisation 101

Wednesday, 28 March, 2012

The Guardian have been forging ahead with the whole “data journalism” area (and I guess I should mention their book!!) and have been doing a remarkable job in ferreting out interesting datasets, finding links/stories (and lets face it, The Telegraph’s MP expenses story doesn’t really get any bigger, and it was all data), developing online visualisations and making the data available. It’s a fascinating area and one the deserves to be developed much more extensively.

Two recent columns are worth highlighting: firstly the Open Data Weekend which features a couple of useful presentations and then a slightly longer, more focused, write-up of the online services they use for visualisation. Well worth a read.

Podcasts for learning

Wednesday, 28 March, 2012

Donald Clark wrote a good blog entry on the usefulness of audio, listening and podcasts for learning. Not least the ability to rapidly re-review, take notes and at faster playback. This all makes sense to me and I like catching up on audio shows, as well as TED videos, when on the move.

And a smartphone makes a lot of sense here in that you can subscribe to RSS feeds and download audio whilst on the move. You can even play back audio whist it is still downloading. On Android there are quite a few choices with BrightHub providing a good review although its a little out-of-date. Google Listen stands out for its search capabilities and integration with Google Reader. However it would appear adding the feature for increasing the play speed (a real time saver!) is more difficult for whatever technical reason. So much so that there is now a third party sound library that has this function called Presto. Several apps have added support for this feature and the Presto page lists some of these. I have been trying the current Beta (and free) ReadItOut Audiobook Player which adds the Presto library. If you just want something very lightweight and simple then you can’t go wrong with either Podcast Player or Tiny Player.

Photos that make you say “OMG!”

Monday, 26 March, 2012

A great selection of historic photos that just shout “O MY GOD”. Fantastic!

Links roundup

Thursday, 22 March, 2012

A few links to follow up:

1. I don’t normally plug other institutions, but this site outlines a link-up between Faro and UCL and, basically, scanning a few locations to try to get on the BIM bandwagon. Its fun to play with the pointclouds though and see the direction people area headed.
2. Britain from Above: summary page of the English Heritage project to scan ~100K aerial photos dating from 1919. Due to go live this year and should be a wonderful historic resource. Watch this space.
3. Astun Loader: Astun have released Loader which takes the underlying OGR and allows easy conversion of GML/KML to other formats. Specifically designed to focus upon loading Ordnance Survey GML in to other formats/databases. useful.
4. TanDEM-X: TanDEM-X has now imaged the entire planet with good, medium and poor data. Mission well on track and results looking, well, exciting!

GEO-12 roundup

Thursday, 22 March, 2012

I attend the GEO12 trade show yesterday….. it’s hardly the most salubrious location (Holiday Inn in Elstree) but the space is reasonable and, well, its free and yes, you do get a free lunch!! More than that, it is doing a good job of combining the GIS and survey world.

Building Information Management (BIM) was the focus for the first session…. not the most exciting topic, but I can see this has the potential to transform building management from design, through build, delivery and maintenance. Key area to watch and there is plenty of money in the sector to make it work (and make it save money).

For me, the “fun” topics close to my interests were in the remote sensing. UAVs were a big focus at the show with both SeneseFly and Gatewing in attendance. Presentations were good from both although pizazz goes to SenseFly…. they went from packed to ready-to-launch with engine running **in the conference room** in 30 seconds!!! (I’ve blogged before on Gatewing). Some of the key aspects were:

  • total weight and payload. SenseFly total weight is under 500g to simplify licensing, Gatewing is 2kg with research looking at larger payloads
  • accuracy is an issue with both UAVs flying compact cameras. The Gatewing is 10MP but both resolution and camera quality limit accuracy. The ability to fly a DSLR would significantly improve imagery
  • the key point is software. Both offer orthphoto and DEM processing, but didn’t really explain how they did it (one assumes SfM type processing, possibly involving open-source libraries). We are getting close to the stage where these are mature products - yes, payload and cost are issues, but expect these to drop dramatically over the coming years
  • licensing - really key issue. These come under CAA regulations and require licensing as unmanned aerial vehicles flown under line-of-sight. Apparantly this is 500m horizontally and 400ft vertically (not sure why Gatewing switched from metric to imperial!). They have an extended license allowing them to operate at upto 750m

Its horses for courses when it comes to aerial systems: my biggest complaint with UAVs is payload, licensing and cost. These demos do nothing to alleviate these problems particularly, but things are headed in the right direction.

The final company was Spheron who specialise in full 306 degree imaging using a high dynamic range camera. In short, an SLR will take images with a small dynamic range (read radiometric resolution), this is 8-bit or about 5-10 f-stops. The human eye can see 18-20 f-stops. The Spheron is 32-bit at upto 28 f-stops. This allows you to image things across all contrast levels that are simply not possible with traditional cameras. Applications?? Two main areas:

  • Computer rendering: place the camera at a location in a real photo and image the scene. Use the light information to accurate render a computer model in the scene. The results are stunning
  • Asset Management: image different locations allowing you to get full 360 degree HDR imagery of assets.

The camera can operate in stereo (vertical offset), but currently is limited to manual, single, point measurements. An automated process is under investigation.

Pedagogic History

Wednesday, 21 March, 2012

Donald Clark has started a blog marathon looking at a history of pedagogic practise. Its a self-selected list and will inevitably not include those you think it could or should….. but if you want to get a flavour and feel for the scope and extent then it makes fascinating reading. And in good academic style, there are plenty of references to follow up on.

A must read.

Testing 3D landform quantification methods with synthetic drumlins in a real digital elevation model

Wednesday, 21 March, 2012

Hillier, J.K. and Smith, M.J. (2012)

Metrics such as height and volume quantifying the 3D morphology of landforms are important observations that re?ect and constrain Earth surface processes. Errors in such measurements are, however, poorly under-stood. A novel approach, using statistically valid ’synthetic’ landscapes to quantify the errors is presented. The utility of the approach is illustrated using a case study of 184 drumlins observed in Scotland as quanti?ed from a Digital Elevation Model (DEM) by the ‘cookie cutter’ extraction method. To create the synthetic DEMs, observed drumlins were removed from the measured DEM and replaced by elongate 3D Gaussian ones of equivalent dimensions positioned randomly with respect to the ‘noise’ (e.g. trees) and regional trends (e.g. hills) that cause the errors. Then, errors in the cookie cutter extraction method were investigated by using it to quantify these ’synthetic’ drumlins, whose location and size is known. Thus, the approach deter-mines which key metrics are recovered accurately. For example, mean height of 6.8 m is recovered poorly at 12.50.6 (2s) m, but mean volume is recovered correctly. Additionally, quantification methods can be compared: A variant on the cookie cutter using an un-tensioned spline induced about twice (1.79) as much error. Finally, a previously reportedly statistically significant (p=0.007) difference in mean volume between sub-populations of different ages, which may reflect formational processes, is demonstrated to be only 30-50% likely to exist in reality. Critically, the synthetic DEMs are demonstrated to realistically model parameter recovery, primarily because they are still almost entirely the original landscape. Results are insen-sitive to the exact method used to create the synthetic DEMs, and the approach could be readily adapted to assess a variety of landforms (e.g. craters, dunes and volcanoes).

‘The Physical Landscape of Britain and Northern Ireland’: a project to increase geomorphological awareness

Wednesday, 21 March, 2012

Hooke, J.M. and Smith, M.J.
Scottish Geographical Journal

A project has been initiated that will produce an interactive website searchable by maps and database terms, aimed at increasing knowledge and awareness of the geodiversity, landforms and processes of Britain and Northern Ireland,. It has the following objectives: (1) to make existing knowledge on the physical landscape and geomorphology of Britain more widely accessible; (2) to increase knowledge and awareness of physical attributes of the landscape; (3) to provide a synthesis of present knowledge; (4) to identify gaps in present knowledge as a platform for future societally relevant research. The components and steps in the project are outlined.

Leaves in Near infra-red

Wednesday, 21 March, 2012

During my course on Remote Sensing last year I was trying to drive home to the students that EM radiation is comprised of different wavelengths and that Earth surface features reflect radiation very differently at different wavelengths. Vegetation is a nice example to use because of the dramatic change of reflectance from red to near infra-red (NIR). And you can show this even better by imaging vegetation they are familiar with.

Using my Nikon D70 which is particularly sensitive to NIR I photographed a dead leaf and live leaf in red, green and NIR (below). The postcard (click on it to get a hi-res version) shows each “band” as a greyscale image and you can clearly see the low reflectance in red and green and high reflectance (white) in NIR. The dead leaf still reflects more in NIR, but the difference is far less pronounced; indeed reflectance is nearly equal across all three bands which is why the leaf appears brown in the false-colour composite (bottom right) whilst the live leaf is red.

Freemind location

Wednesday, 21 March, 2012

I blogged on Freemind, the open source mind mapping software, a few days ago, but wanted to add on to that post. The development team are reaching a v1.0 release candidate (currently in Beta) and have incorporated the ability to add location to nodes on your mind map. Tools -> Map (or Ctrl-Alt-M) brings up the Map window which loads OSM data of Europe. Type in the “Search Location” bar the place you want to add and hit enter. The location pointer is centred at this location. You can now:

  • zoom in to look at this in more detail.
  • move the point - or rather, single-click anywhere in the new window to place the pointer somewhere else
  • click Actions -> Place Selected Nodes to add the location to you node
  • double-click to place a new node in your mind map at that location

All very useful and interesting functions and good to see OSM integrating and enabling such a feature. It will be interesting to see how this develops.