Wikipedia:Reference desk/Archives/Computing/2012 September 18

= September 18 =

Clean Python code [APT/Ubuntu]
Hi. So... I have this somewhat simple python program It's function is to display a simple GUI, and if the user clicks in the option "install vlc", it will install vlc. However, I want to completely skip the initial GUI and I am only interested in automatically launching the vlc installation when the script is launched... I assume it is pretty easy, but since I barely know any python... Thanks. --Hacktolive (talk) 02:38, 18 September 2012 (UTC)


 * Based on the documentation here, I suppose this will work:


 * Untested, though. -- BenRG (talk) 04:59, 18 September 2012 (UTC)

Microsoft Outlook Scroll Bar
Caould you give me any ideas on why my scroll bar on Microsoft Outlook takes off a great rate of speed when I am looking at emails. This has happned a couple of times and I am wondering why.

Many thanks

Ann Johnson — Preceding unsigned comment added by Johnoowen (talk • contribs) 04:28, 18 September 2012 (UTC)
 * Are you on a laptop with a touchpad? That'd be my 1st guess. Vespine (talk) 05:05, 18 September 2012 (UTC)


 * Could it be the down arrow on the keyboard sticking down ? StuRat (talk) 05:55, 18 September 2012 (UTC)


 * If you (like most these days) use an infrared mouse it could be that causing it. My pointer at work randomly moves ocassionally without my mouse moving (at least without me moving the mouse) and sometimes causes Excel to scroll quickly down. I've always put it down to being on an uneven/imperfect surface and the infrared getting confused. ny156uk (talk) 20:23, 18 September 2012 (UTC)

Animated weather radar maps
They always seem to have too few frames, so it looks very "jumpy", whether on the Internet or the TV news. What's the problem ? Why can't they capture enough frames to make for a smooth animation ? StuRat (talk) 06:23, 18 September 2012 (UTC)


 * Weather satellites do not shoot video at 30 frames per second, as standard video is. There is no need, the weather doesn't change that fast. I do not know the exact frame rate, but from watching satellite video, my estimate is about a frame per minute.  → Michael J Ⓣ Ⓒ Ⓜ 07:25, 18 September 2012 (UTC)


 * Weather satellites, like those in our GOES fleet, are not the source of weather RADAR imagery. You can see a full listing of GOES' data products here: GOES Products and Services; or peruse the main website at http://www.goes.noaa.gov/ .  Nimur (talk) 14:55, 18 September 2012 (UTC)


 * I suspect that's even too high. The animations at weatherspark.com are a frame every five minutes, and look like "standard" framerates to me. --Mr.98 (talk) 14:29, 18 September 2012 (UTC)


 * Now, how many frames they would need to make it look smooth depends on the magnification level. For a map showing the entire Atlantic Ocean, say to watch a hurricane develop, probably one frame an hour would look smooth.  On the other hand, a map of the weather in a town might need one frame per minute to smoothly show how a storm is moving through the area. These frames are then sped up, of course, for display, say to 30 frames per second.  This would make the hurricane tracking for a week take about 6 seconds to play, and the storm moving through a town might take 6 seconds to show the last 3 hours.  StuRat (talk) 15:09, 18 September 2012 (UTC)


 * I guess because ground based weather radar has to gather height information as well as distance, so they use a series of elevation angles, which takes time to complete (5 to 10 minutes max according to the article). Satellite radar would face the same problem, having to scan the surface in a series of consecutive lines.
 * For ground based radar images there's also the task of combining data from all stations into one global map. Ssscienccce (talk) 08:06, 18 September 2012 (UTC)


 * A doppler radar unit only scans a straight line, so they have to rotate it to capture the full image. You'll see this when they show the live radar - the line rotates around the location of the radar dish, updating the image as it scans. 209.131.76.183 (talk) 11:46, 18 September 2012 (UTC)


 * Googling around, I don't see any inherent reasons why it couldn't be done; it would just require optimizing the equipment to that outcome, and probably require new equipment. I doubt they are downgrading the frame rate from what the data is giving them; it probably just doesn't sample data at higher rates than that. --Mr.98 (talk) 14:29, 18 September 2012 (UTC)

Most weather RADAR you see in the United States comes from the National Weather Service's nationwide network of WSR-88D doppler RADARs. The "88" indicates technology from 1988. There have been many many upgrades to the system, but the core RADAR is actually very old. Many experts predict a next generation of RADARs will be available in the near future; here is one page from NOAA: RADAR improvements... Of course, to get a nationwide upgrade, the cost has to be justified and budgeted. StuRat, you may also be interested in NOAA RIDGE2, which is how I always watch RADAR. It is fed from the same doppler transmitters, but displays a configurable data product, including the new 1x1km super-resolution. Here's a link for RIDGE2 near Palo Alto Airport. You might also find DUATS useful: it is a telephone- and internet-enabled user interface for weather and flight planning, organized by the FAA. Again, its RADAR feed is still the same NEXRAD network; but there are additional features and advanced data products available. Nimur (talk) 14:46, 18 September 2012 (UTC)


 * Thanks. I looked at the RIDGE2 site.  It seems to provide a map of current weather, updating every 5 minutes.  I saw options for loop speed (slow, medium, fast), but didn't actually see an option to play it in a loop.  Am I missing something ?  Also, in my experience, the "slow, medium, fast" choices don't change the number of frames, but just how long they hold each frame on the screen.  So, no matter what speed you pick, it still looks jumpy.  They also have an "Update now" button.  I'm not sure what this does.  I doubt if it actually displays a map generated that second.  Perhaps it just means "display the most recent map we have, of the selected type", which, of course, could be quite old.


 * As for DUATS, it looks like only pilots are allowed to use that system. StuRat (talk) 15:01, 18 September 2012 (UTC)


 * RIDGE is a user-interface - "(Radar Integrated Display with Geospatial Elements)" - to various RADAR products. It lets you feed in different RADAR data, and integrates it into a "map" display.  If you want access to raw data products, so you can design your own user interface, you might find NOAA's Radar Product Central Collection Dissemination Service useful.  Depending on the level of access you need, many of the interesting data is available free of charge.  Here is a very high-level overview of some different types of data that you can view.  Nimur (talk) 20:36, 18 September 2012 (UTC)


 * Are there any options for increasing the number of frames (reducing the interval between frames below 5 minutes or increasing the total time in the loop) ? A total of 10 frames is bound to look jumpy. StuRat (talk) 22:04, 18 September 2012 (UTC)


 * Right above the loop speed option is an option to turn looping on and off. It looks like it loops 45 minutes at 5 minute intervals. I don't see a way to cover a longer period. 209.131.76.183 (talk) 17:20, 18 September 2012 (UTC)


 * Thanks. I had tried that, with no visible results.  Apparently I just had to let it wait longer, to build the animation, before it would display. StuRat (talk) 22:02, 18 September 2012 (UTC)


 * This is one of those areas where the NATIONAL Weather Service could provide a better service to the public if the public were willing to give it more money. (Comment from a past employee of another country's national weather service.) HiLo48 (talk) 17:40, 19 September 2012 (UTC)

Screencasting software
Hi, I'm looking for a decent, free, screencasting program. I've checked out our article, and I'm really just inundated with options. Is there a general favourite of the "typical" consumer, ie. the one who wants a few simple features for doing a Youtube video to instruct people on something (in my case, an app I'm designing)? t.i.a. IBE (talk) 18:20, 18 September 2012 (UTC)
 * I've used CamStudio, it's a little buggy but the best of all the ones I tried. VLC comes second place but it has no advanced options - you can only record the entire screen, not specific windows or parts of the screen. 92.233.64.26 (talk) 19:48, 18 September 2012 (UTC)

Thanks - has anyone tried Screenpresso? That's the other one I'm thinking of - or I might try both, since I suspect it's easy enough to learn software like this. IBE (talk) 20:03, 18 September 2012 (UTC)


 * I spend ages trying out different ones for producing in-house training videos. The main problem that I found with CamStudio is that the video produced was in it's own format and I couldn't covert it to anything "sensible" such as mp4 or flash.  The converted files just played the initial opening frame for the entire length of the video, or were distorted in all sorts of strange ways.  The one that I had the most success with was Wink (tutorial software).  This produces flash as the output, you can capture either individual frames (a series of screen shots), or it can capture continuously or it will capture if an event occurs eg pressing a key or clicking the mouse.  You can mix all three within the same video.  Frames can be annotated with arrows, circles around areas, etc.  Narration can be added afterward, which worked especially well when a there was a series of screen shots.  There are too many "tutorial videos" on youtube containing (for example) "err umm, I'm just err umm err logging in and errr...." and feature wild random mouse movements.  It's damn hard to get a perfect run doing a screen capture and doubly so if you are trying to record narration at the same time. --TrogWoolley (talk) 21:16, 18 September 2012 (UTC)


 * I think the eyes have it *wink* IBE (talk) 21:52, 18 September 2012 (UTC)

I use Camtasia Recorder