the hard to read graph
Here is the network graph I made using the code bellows,but it's extremely hard to read.Is there anyway to make it easier to read? And how to avoid the overlaps of edges and labels?
l<-layout.random(wcen_graph)
plot.igraph(wcen_graph,vertex.shape="circle",layout=l,
edge.arrow.size=0.06,edge.width=E(wcen_graph)$Weight,
vertex.label.dist=-0.3)
Many thanks in advance.
Related
After browsing for a while for available solutions, it is really hard to choose the most appropriate tool for creating dashboard & populating it with plots. I would want to have an html page with multiple plots and tables depicted. I'm thinking to have data input stored in csv files, appropriately formatted.
The requirements are:
plot coordinates are showing on mouse hover
ability to show coordinates of points on a plotted line (points in
scatter plot or bar values for bar chart) 'sticking' to the nearest
lines on hover, with appropriate handling of multiple lines (show several y values for same x)
ability to interactively switch plotted data on/off
easily embeddable into html page, doesn't require additional plugins installed
a good variety of plot types
not too slow to load and stable, there could be ~50 plots on one page
(this is for internal use only, so quickness is not that important)
does it all with minimal effort
So far I checked out (by no means a final opinion, correct me if I'm wrong):
gnuplot+canvas - looks good, but samples on their page fail to work
well for me, not always getting mouse clicks right
python+matplotlib+mplh5canvas - feels a bit raw, as I understand
some of the stuff above I'd need to implement in Python myself
RGraph looks awesome at first glance, not sure if it is good since never heard of
it and don't have any experience in js, hard to customize(?)
some other random stuff which seemed bad enough
Suggestions?
RGraph looks awesome, and is awesome. It's not difficult to use and there are a lot of examples online.
Rgraph Example page
They've got 22types of graphs, correct me if I'm wrong, and as I already said, easy to use.
Documentation about possibilities and stuff for each type of graph is also available on the website.
I end up using Highcharts because of its very advance features and ready-to-use templates (in addition to the things mentioned in the question).
I'm researching the following problem:
Let's say I have a glass of some fluid (water for example). The fluid is completely transparent and I don't have to render it at all.
However a ink drop is dropped in the glass and it's spreading in the water.
The whole thing should be 3D and user should be able to rotate the camera and see the spreading in real time.
I have researched a couple of way to approach this problem, but it turned out that most of them are dead end.
Тhe only approach that has some success was to use enormous amount of particles which form the skeleton of the "inc spread". The physics simulation of the process of spreading is far form perfect, but let's say it's not a problem.
The problem is the rendering part.
As far as I know I'll not be able to speed up the z-sort process greatly by using the flash GPU acceleration, because the upload of those particles to the GPU memory every frame is quite slow?
Can somebody confirm that please?
The other thing that I'm struggling with is the final render. I tried a whole bunch of filters in combination with "post process" techniques to create smooth lines and gradients between the dots, but the result it terrible. If somebody know some article that could help me with that I'll be very grateful.
Overall if there is another viable approach tho the problem please let me know.
Thanks in advance.
Cheers.
You should probably look at Computational Fluid Dynamics in general to get a basic understanding. This should make it easy to play with actionscript implementations like Eugene's Fluid Solver, either in 2D or 3D, tweaking fluid properties to get the look and feel you're after
I am a beginning programmer and I really want to have good habits and practices. I have yet to slice up a PSD and code it. Is this a bad practice? I have heard it creates bad code that had to be fixed anyway so why do it? I want to create clean code even if it takes longer. Just wondering if it is as bad as I have heard. Are there advantages to doing it this way? Do I need to learn this skill to make good sites? Thanks.
If your images are very large, then sometimes slicing them into pieces and generating the right HTML that lines up all the pieces can be a better user experience. These days, this seems to matter more for those on very slow links (like dial-up) or very poor links (lots of errors) and less for those on typical internet links unless the images are very large.
Overall, slicing images is more overhead for the browser (more HTML, more separate image request for both client and server) so it's only beneficial when specifically needed to solve a problem. I would not do it by default unless you had a specific problem you were trying to solve with the image slicing.
Your background image shouldn't be a very complex image and if it is try to make it as optimized as possible so the load time is efficient for slower downloads. As for slicing I wouldn't use it all that often as it does cause alot of browser requests, again be sure all are optimized so the download time is very minor. Something to look into is using sprites (I know it wasn't the question) these are very useful for images that don't really matter to SEO of the site (buttons, arrows, bullets, etc. The big thing anymore is download speed you want to keep the images cached, optimized and as minimal bandwidth as possible. If your page takes too long to load then your users will leave, that should drive your image create more than best-practices.
So I was looking at the facebook HTML with firebug, and I chanced upon this image
and came to the conclusion that facebook uses this large image (with tricky image positioning code) rather than many small ones for its graphical elements. Is this more efficient than storing many small images?
Can anybody give any clues as to why facebook would do this.
These are called CSS sprites, and yes, they're more efficient - the user only has to download one file, which reduces the number of HTTP requests to load the page. See this page for more info.
The problem with the pro-performance viewpoint is that it always seems to present the "Why" (performance), often without the "How", and never "Why Not".
CSS Sprites do have a positive impact on performance, for reasons that other posters here have gone into in detail. However, they do have a downside: maintainability; removing, changing, and particularly resizing images becomes more difficult - mostly because of the alterations that need to be made to the background-position-riddled stylesheet along with every change to the size of a sprite, or to the shape of the map.
I think it's a minority view, but I firmly believe that maintainability concerns should outweigh performance concerns in the vast majority of cases. If the performance is necessary, then go ahead, but be aware of the cost.
That said, the performance impact is massive - particularly when you're using rollovers and want to avoid that effect you get when you mouseover an image then the browser goes away to request the rollover. It's appropriate to refactor your images into a sprite map once your requirements have settled down - particularly if your site is going to be under heavy traffic (and certainly the big examples people have been pulling out - facebook, amazon, yahoo - all fit that profile).
There are a few cases where you can use them with basically no cost. Any time you're slicing an image, using a single image and background-position tags is probably cheaper. Any time you've got a standard set of icons - especially if they're of uniform size and unlikely to change. Plus, of course, any time when the performance really matters, and you've got the budget to cover the maintenance.
If at all possible, use a tool and document your use of it so that whoever has to maintain your sprites knows about it. http://csssprites.org/ is the only tool I've looked into in any detail, but http://spriteme.org/ looks seriously awesome.
The technique is dubbed "css sprites".
See:
What are the advantages of using CSS
Sprites in web applications?
Performance of css sprites
How do CSS sprites speed up a web
site?
Since other users have answered this already, here's how to do it, and another way is here.
Opening connections is more costly than simply continuing a transfer. Similarly, the browser only needs to cache one file instead of hundreds.
yet another resource: http://www.smashingmagazine.com/2009/04/27/the-mystery-of-css-sprites-techniques-tools-and-tutorials/
One of the major benefits of CSS sprites is that it add virtually 0 server overhead and is all calculated client side. A huge gain for no server side performance hit.
Simple answer, you only have to 'fetch' one image file and it is 'cut' for different views, if you used multiple images that would be multiple files you would need to download, which simply would equate into additional time to download everything.
Cutting up the large image into 'sprites' makes one HTTP request and provides a no flicker approach as well to 'onmouseover' elements (if you reuse the same large image for a mouse over effect).
Css Sprites tecnique is a method for reducing the number of image requests using background position.
Best Practices for Speeding Up Your Web Site
CSS Sprites: Image Slicing’s Kiss of Death
Google also does it - I've written a blog post on it here: http://www.stevefenton.co.uk/Content/Blog/Date/200905/Blog/Google-Uses-Image-Sprites/
But the essence of it is that you make a single http request for one big image, rather than 20 small http requests.
If you watch a http request, they spend more time waiting to start downloading than actually downloading, so it's much faster to do it in one hit - chunky, not chatty!
I'm working on an application that needs to key out the background from an image taken by a webcam in front of a green screen. I figured this would be a very common task, but to my surprise i'm having trouble finding code samples for anything more advanced than a simple color-threshold and those do not quite cut it quality wise.
I've found a few pdf-papers, but I'm having trouble translating these rather high concepts into actual implementations, I'd much rather look at some code.
Focus here is on quality, having a second or more of processing time is not a problem.
I will be using actionscript 3 (and possibly pixel bender) to implement this, but I'll happily look at other languages aswell.
If you have any good samples doing this, the whole process or parts, please do post them!
If you have no high requirement for chromakey quality, maybe this(http://www.quasimondo.com/archives/000615.php) will be okay.
But for high quality video( i.e, 720*576 video ), it is not easy job.
I have spent a lot time to research high quality chromakey algorithm, finally I have figured out one algorithm(implemented with c/c++) for real time video,which can be used in none-linear video editing system as plugin or standalone application.
I put some demo static images to show at voicethread.com websites, everyone can comment with text, or voice there.
http://voicethread.com/share/801789/