Yenya's World

Thu, 30 May 2013

GPS Tracking Systems

I use my smartphone in addition to the cyclocomputer in order to be able to record my speed, and later compare the speeds at the same place amongst various conditions. The problem is what to use for tracking and what for reviewing and comparing the recorded tracks?

So far I record the tracks using Move! Bike Computer on my Android phone. It is far from ideal, but at least it stores tracks as a GPX files which are accessible directly from the flash. It uses 1-second intervals, and as a bonus, it can display the track using Google maps. The drawback is that it sometimes does not switch the GPS on, so it needs to be switched on manually from the Android top bar menu. The other drawback is that while it can send the GPX files by e-mail to the desktop computer, it does not remember the prefered export format (GPX instead of KML for me) and the prefered export method (e-mail using K-9 mail to a predefined address). So sending tracks from my phone for further archivation is not so easy. But at least it can be done. Another problem is the start and end of the track: I usually start this app before leaving home, and stop it some minutes or hours after reaching the destination. The recorded tracks then cannot be easily compared, because their durations vary in the order of tens of percent, even though the real time of activity is roughly the same. The auto start/stop feature of the cyclo computer is much more precise - the GPS always report at least some movement because of its imprecision and noise.

As for the viewer, the situation is even worse. So far the best I have found is Endomondo, (and "the best" here does not imply "good" at all). Endomondo can import the tracks in the GPX format, and display them on top of Google map, can generate the speed and height profile, etc. On the other hand, it is way too skewed to training and fitness (computing calories, etc.), and has way too much useless social features. It also has its own proprietary Android App, which makes sending data to Endomondo easier, but with this app it is impossible to get your own data back in an open format. Moreover, when importing GPX data with 1 second granularity, Endomondo rescales it to something more coarse (tens of seconds to even minutes), so it makes comparing the speed at a given place pretty meaningless.

What do you use for your sports tracking, and how does it meet your data accessibility and openness requirements?

Section: /computers (RSS feed) | Permanent link | 0 writebacks

Wed, 29 May 2013

E-shop Reviews

Apparently at they think that they sell only perfect goods, and don't want people to write negative reviews to some of the goods, even though the description contains plain lies. As an example, we take this 9V rechargable battery. In the description, they say:

The rechargable NiMH battery from GP Batteries lasts up to 5 times longer than alkaline batteries [...]

There has to be some serious magic used by either Mall.CZ or GP Batteries, which causes that the battery rated at 8.4 V with 200 mAh capacity lasts five times longer than an ordinary 9V primary alkaline cell. Apparently the later according to Wikipedia has 565 mAh capacity, and thus stores three times more energy than the rechargable batery from GP Batteries.

I have written a comment along these lines to the Mall.CZ system on May 7th, but it is still not published as of now. So beware of any e-shop which doesn't allow negative comments, such as Mall.CZ. It is interesting that some bigger shops like DX are perfectly OK with people writing negative reviews to some of their goods.

Section: /world (RSS feed) | Permanent link | 1 writebacks

Fri, 24 May 2013

File Manager

The last file manager I have used was Norton Commander back in the DOS era. Many years after that, during the flame wars between proponents of spatial and single-windowed Nautilus, I have only laughed at them, thinking that the command line was much better. Why would anybody need a GUI file manager? I feel slightly ashamed now, but I have to admit that for the last two weeks, I have also been using a GUI file manager.

I work on various things with respect to cabling, electricity, a new datacenter, and so on in the new building of Faculty of Informatics. The problem with the building specifications, projects, and so on is, that they are stored in the deep structure of directories, with names containing whitespace and even non-ASCII characters (in different character sets), and each directory contains many files or subdirectories with common prefixes shared by a set of files. So the usual tab-completion does not help - it is necessary to actually look at the completion prefix in order to know what character to add next. Here is an example of such a file name, starting from my automount point:

FIMU_GD_SOD_příloha č. 1/!!!_02_FIMU_GD_SoD_Priloha_1_II.A_PD_DVD_PROJEKTOVA_DOK_1.etapa!!!/\

In order to be able to quickly navigate inside such directory tree, I have started to use a GUI file manager. So far I use Thunar, the default file manager in XFCE. It can easily switch to any directory along the current path, and it has bookmarks for fast access to frequently-used directories. I use this feature a lot, because of the main drawback of GUI file managers: It is not possible to descend into a directory, which is an automount point (and which, from the VFS point of view, does not exist yet).

Do you use a GUI file manager?

Section: /computers/desktops (RSS feed) | Permanent link | 4 writebacks

Tue, 21 May 2013

Cell Phone Operators

Few weeks ago I have moved my cell phone number to a different phone operator (don't ask :-). Today, I've got an interesting call:

Caller: "Hello, I am a representative of $my_new_operator, do you have a minute or two?"

Me (thinking about possible problem with $my_new_operator, with payments, or whatever): "Well, only a minute."

Caller: "OK, then. We have a great offer for customers of $my_old_operator. If you move to $my_new_operator, you can save much money."

Apparently the $my_new_operator's representative does not know that I am already their customer.

Section: /personal (RSS feed) | Permanent link | 2 writebacks

Fri, 03 May 2013

Laptop Upgrade?

I've got my laptop, ASUS F3E, in September 2008. So maybe it's time for a new laptop. Last year I have briefly considered buying a new one, but I have found that after upgrading F3E to 4 GB of RAM, 9-cell battery, and a fast solid-state disk (OCZ Vertex 2), then-current models provided no significant improvement compared to my F3E. Is this year's offer better?

There are several problems with my F3E:

What parameters should my hypothetical new laptop have? Of course, it would need to be better than my upgraded F3E in every aspect, and meet the following criteria:

Does such a laptop exist, my dear lazyweb? Or shall I stay with my upgraded ASUS F3E for another year?

Section: /computers (RSS feed) | Permanent link | 10 writebacks


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