Interesting Tech Projects
Andy
Located in Tucson, Arizona, USA
Homepage: http://www.britishideas.com
Posts by Andy
Poster Map of East Yorkshire
Jan 19th
Using data from the OpenStreetMap project (taken a couple of days ago) along with some utilities such as Maperitive and custom software, I have generated a 39 inch x 31 inch poster of the East Riding of Yorkshire. This map includes hillshading and contour lines and individual streets can be seen.
Some assembly is required. Print it out on A4 paper, cut out the sheets and then glue them together. Download it here.
Here is a sample:
So You Want to be a Cartographer?
Jan 16th
Love maps? Want to make your own? Now it’s easy thanks to a set of free software.
Previously I wrote about the OpenStreetMap project, which allows anyone to edit a map of the world. People can add points, lines and areas and “tag” them to show what they are. Once the data is uploaded a new version of the map is generated for everyone to see.
For example I could create a point on the map and tag it with “railway=station” to indicate that it is a train station. I could draw a line and tag it with “highway=residential” to mark the line as a residential road. I could also draw an enclosed area and tag it with “landuse=forest” to show that the area is a forest. There are many different tags that can be used to represent all kinds of things that appear on maps.
This article is in the form of a tutorial to get you quickly started creating your own maps. I will introduce the software involved and show how to use it step by step. The result of the tutorial is a map of the North Yorkshire Moors Railway, which is a steam train service on a historic train line in England and is featured in the Harry Potter films.
Driffield Train Time Lapse
Jan 1st
A five second video I made today from the footbridge of a Hull to Bridlington train stopping at the station in Driffield. As the train arrives in the station you can see the level crossing barriers behind it go up and traffic resume.
Optimizing DeepEarth For GIS Mapping
Sep 5th
DeepEarth is an interesting Silverlight project. It allows interactive tile-based maps to run in a browser with overlays of custom data, however it suffers from some performance problems.
Large GPS Track Logs
I had the need to display GPS tracks in DeepEarth. GPS tracks can contain thousands of points. DeepEarth has three update modes called ElementUpdate, PanOnlyUpdate and TransformUpdate for showing features such as tracks:
- ElementUpdate recalculates the point positions on every map movement. This produces an accurate track display but gets slower as the number of points increases.
- PanOnlyUpdate recalculates point positions during panning and hides features while zooming. Not too useful for me and didn’t seem to show anything anyway.
- TransformUpdate draws the tracks to the map once then scales and pans the vector graphic in synchronization with the map. This makes it very fast. Sadly the scaling code is flawed. Lines disappear as you zoom in and sections of the tracks become distorted, almost looking like calligraphy.
I wasted many evenings trying to get the scaling in TransformUpdate mode working before giving up. I then turned my attention back to the ElementUpdate mode to see where the bottleneck is. More >
Smooth Zooming and Panning Time Lapse
Jul 14th
I have worked out a method to allow zooming and panning for time lapse movies. More work is still needed, but here is a short sample of storms last Saturday.
Forest Fire Time Lapse
Jul 12th
Here is another time lapse, this time of a five acre forest fire on the mountain range outside of Tucson. The fire is about 10 miles away. The time lapse was created using 10MP images with the camera at full 3x optical zoom. The images were then cropped to 1920 x 1080 to create a high definition movie.
The total elapsed time shown was one hour and 41 minutes, compressed into two minutes at 24 frames per second.
Motorized Panning During Time Lapses
Jul 7th
A time lapse video can be made to look really good if the camera is panned while the picture taking happens. The result is smooth motion during the video, and there are plenty of examples of this on You Tube.
There are lots of ways to make cheap panning mechanisms, with the most popular involving an old egg timer. However these approaches have some limitations:
- Once the panning starts you don’t stop it, even if you panned away from an area where something happened 10 minutes after the start
- The panning is typically a linear motion – the same speed all the time
- Most panning mechanisms do not have vertical panning, only horizontal
Number one comes from the limitation of having to set up the motion before starting to take the pictures. It can be difficult to anticipate in advance what might happen in the scene and once it does even if the motion was somehow changed, it would have to change slowly to avoid disrupting the video in a jarring way, missing the item of interest anyway.
Number two can be solved by using a PC or microcontroller to control the camera motion in more complex ways. However this is added time and expense for design and setup.
Number three can be solved by using two motors, one for horizontal and one for vertical. Again, unless the motion is very simple and defined in advance, a PC or microcontroller would be needed.
Tucson to Phoenix in Less Than Three Minutes
Jun 29th
Another time lapse, this time of a trip I took yesterday. Created using a Canon A480 and CHDK.
Storms Time Lapse
Jun 28th
Here is another time lapse of storms building over the Santa Catalina mountains. The black specks that keep appearing are birds going to and from our bird feeders.
It was generated with 3750 pictures taken two seconds apart using CHDK.
Yorkshire Pudding Time Lapse
Jun 19th
Here is another one – it’s a strange angle because I needed to keep the oven light out of direct view of the camera. Total time elapsed was 20 minutes. Compressed to 33 seconds. Generated using a Canon A480 and CHDK.
