Re: [time-nuts] web presentation of data

[Hal Murray]

jim...@earthlink.net said:
> what would be useful is to have some sort of "plotting engine" that is a
> canned webpage (or stored locally on the user/client computer) that can
> ingest fairly raw data from a URL.. 
...
> A low end microcontroller has no problem serving readonly pages from  flash/
> SD, it just has a tough time doing graphics. 

I'd do something like that in two separate steps:
  The microcontroller would collect the data.
  A separate job on a real computer would occasionally grab the data.

I'm assuming we are discussing some sort of long running project.  The real 
computer has a bigger disk and some sort of backup/archiving setup so I'd 
want to get the data there anyway.  Once it's there graphics isn't a problem.




-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] web presentation of data

[John Ackermann N8UR]

I think there are now a couple of threads going on about this topic, 
which I started by a clumsy attempt to use the "WIDTH" and "HEIGHT" 
attributes in HTML. :-)


For what it's worth, I usually scale web graphics to no larger than 750 
pixels horizontal or 550 pixels vertical.  That goes back to the days of 
lower resolution monitors, but still works well with the page layout I 
use at febo.com.


The challenge in this case was that using the default settings in John's 
TimeLab program, I'm getting plots that are about 1350 pixels wide and 
(as PNGs) are ~130kB in size.  When down-sampled, it can become 
difficult to read the fine data.  The best way to handle that, I think, 
is to create a scaled version of the image and use that as a link to the 
full-size version.  Something like:




But that's extra work that I haven't gotten around to automating yet, so 
I thought I'd try using the HTML size options:




The viewer can then right-click on the image and via the "view image" or 
similar menu open up the full-sized version for the fine detail.  That 
worked on my browser and monitor, but apparently not on some other 
combinations.  So, it's back to the drawing board.


Moving to the second thread on plot generation generally, apart from 
TimeLab I do most of my data capture and analysis in Linux.  I typically 
break the two into separate pieces:


1.  A single-purpose program (usually written in Perl because I make 
slightly fewer errors with it than other languages) that talks via GPIB 
or serial port and outputs a data file with typically MJD and phase or 
frequency information.


2.  A graphing tool that reads the data file.  For this, I'm quite fond 
of a program called "Grace" (http://plasma-gate.weizmann.ac.il/Grace/) 
that provides a WYSIWIG graphics interface and saves plot information in 
an ASCII format that's pretty easy to muck around with.  Grace is 
packaged with Debian-based Linux distributions; I don't know if there's 
a Windows version available.


I've also done some automatic plot generation to go from data file to 
regularly updated web page.  This involves some fairly ugly text 
processing taking advantage of Grace's batch mode, but the result is a 
tool that will read the data file, do whatever statistics are desired, 
combine with the Grace command file, run Grace in batch mode, and create 
an output PNG file that's uploaded to the web.  It's actually fairly 
easy to do once you figure out the appropriate black magic...


John


On 8/6/2012 11:34 AM, Jim Lux wrote:

what would be useful is to have some sort of "plotting engine" that is a
canned webpage (or stored locally on the user/client computer) that can
ingest fairly raw data from a URL..

something, conceptually, like this:



*invocation of plotting engine*

data value 1
data value 2
data value 3



that way, a relatively dumb controller (think arduino-ish) could talk to
the instrument and build a web page on the fly without having to do much
formatting.  The java/javascript/whathaveyou would do all the plotting
work on the client side (where, presumably, they have a display and some
computational horsepower to drive it)

A low end microcontroller has no problem serving readonly pages from
flash/SD, it just has a tough time doing graphics.


And, if you wanted the raw data, you serve up a page called "raw.html"
or something that just has the raw data.

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Re: [time-nuts] web presentation of data

[Jim Lux]

On 8/6/12 9:16 AM, Hal Murray wrote:


jim...@earthlink.net said:

what would be useful is to have some sort of "plotting engine" that is a
canned webpage (or stored locally on the user/client computer) that can
ingest fairly raw data from a URL..

...

A low end microcontroller has no problem serving readonly pages from  flash/
SD, it just has a tough time doing graphics.


I'd do something like that in two separate steps:
   The microcontroller would collect the data.
   A separate job on a real computer would occasionally grab the data.

I'm assuming we are discussing some sort of long running project.  The real
computer has a bigger disk and some sort of backup/archiving setup so I'd
want to get the data there anyway.  Once it's there graphics isn't a problem.




More like a field data collection system where you want to get at it via 
WiFi and a laptop.  I don't want a PC turned on all the time logging the 
data.  The arduino is perfectly suited to grabbing data periodically and 
writing it into a SD card, from which the webserver code can grab it.




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Re: [time-nuts] web presentation of data

[Pablo Garaizar Sagarminaga]

Hi there,

On Mon, 06 Aug 2012 12:57:00 -0400
John Ackermann N8UR  wrote:

> 
> But that's extra work that I haven't gotten around to automating yet,
> so I thought I'd try using the HTML size options:
> 

It's easy to resize pictures automatically if you are a Linux user
using imagemagick's convert tool:

1) Resize one pic:

convert pic.jpg -resize 50% small-pic.jpg

2) Resize many pics in one directory:

for F in *jpg; do convert $F -resize 50% small-$F; done

Hope it helps O:-)

-- 
  Pablo Garaizar Sagarminaga
  Universidad de Deusto
  Avda. de las Universidades 24
  48007 Bilbao - Spain

  Phone:   +34-94-4139000 Ext 2512
  Fax:  +34-94-4139101

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Re: [time-nuts] web presentation of data

[Chris Albertson]

On Mon, Aug 6, 2012 at 8:34 AM, Jim Lux  wrote:

> what would be useful is to have some sort of "plotting engine" that is a
> canned webpage (or stored locally on the user/client computer) that can
> ingest fairly raw data from a URL..
>
> something, conceptually, like this:
>
>
> 
> *invocation of plotting engine*
>
> data value 1
> data value 2
> data value 3
>
> 
>
>
What you are saying is that the data needs to be rendered to a graphic
locally.   I think the simplest way is to create vector based plots on the
server (I've used GNU Plot inside a CGI script) but there is a system to
pretty much what you are asking for.  http://code.google.com/p/flot/



Chris Albertson
Redondo Beach, California
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Re: [time-nuts] web presentation of data

[Pablo Garaizar Sagarminaga]

Hi there,

El Mon, 6 Aug 2012 10:43:50 -0700
Chris Albertson  comentaba:

> What you are saying is that the data needs to be rendered to a graphic
> locally.   I think the simplest way is to create vector based plots
> on the server (I've used GNU Plot inside a CGI script) but there is a
> system to pretty much what you are asking for.
> http://code.google.com/p/flot/

Indeed, I use flot in AllanJS [1], a JavaScript library to calculate
Allan deviation estimators based on previous work from this list (Tom
Van Baak, Magnus Danielson, William J. Riley, John Miles).

[1] http://txipi.github.com/AllanJS/

-- 
  Pablo Garaizar Sagarminaga
  Universidad de Deusto
  Avda. de las Universidades 24
  48007 Bilbao - Spain

  Phone:   +34-94-4139000 Ext 2512
  Fax:  +34-94-4139101

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Re: [time-nuts] web presentation of data

[Magnus Danielson]

Hi Pablo,

On 08/06/2012 07:59 PM, Pablo Garaizar Sagarminaga wrote:

Hi there,

El Mon, 6 Aug 2012 10:43:50 -0700
Chris Albertson  comentaba:


What you are saying is that the data needs to be rendered to a graphic
locally.   I think the simplest way is to create vector based plots
on the server (I've used GNU Plot inside a CGI script) but there is a
system to pretty much what you are asking for.
http://code.google.com/p/flot/


Indeed, I use flot in AllanJS [1], a JavaScript library to calculate
Allan deviation estimators based on previous work from this list (Tom
Van Baak, Magnus Danielson, William J. Riley, John Miles).

[1] http://txipi.github.com/AllanJS/



I feel honoured to be part of that list of names.

I haven't tried AllanJS yet, but Pablo has informed me of it's existence 
before.


I've done my share of work implementing algorithms, but others are 
better at getting a meaningful user interface done.


Cheers,
Magnus

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Re: [time-nuts] web presentation of data

[Mike S]

On 8/6/2012 12:57 PM, John Ackermann N8UR wrote:



The viewer can then right-click on the image and via the "view image" or
similar menu open up the full-sized version for the fine detail.  That
worked on my browser and monitor, but apparently not on some other
combinations.  So, it's back to the drawing board.


Try 

(assuming a 1350x1012 original). Specifying an exact size is preferred, 
since it makes page rendering faster - the browser can do the layout 
before having to download the image to determine the size.


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Re: [time-nuts] web presentation of data

[Jim Lux]

On 8/6/12 10:43 AM, Chris Albertson wrote:

On Mon, Aug 6, 2012 at 8:34 AM, Jim Lux  wrote:


what would be useful is to have some sort of "plotting engine" that is a
canned webpage (or stored locally on the user/client computer) that can
ingest fairly raw data from a URL..

something, conceptually, like this:



*invocation of plotting engine*

data value 1
data value 2
data value 3





What you are saying is that the data needs to be rendered to a graphic
locally.   I think the simplest way is to create vector based plots on the
server (I've used GNU Plot inside a CGI script) but there is a system to
pretty much what you are asking for.  http://code.google.com/p/flot/




Somehow, I don't think running Gnuplot on a Arduino is feasible.  ABout 
all it can do is respond to the HTTP "Get" with the right page.


That's why I want to push the hard work of doing the rendering onto the 
client (i.e. the browser).  The comm link is fast, and an SD card on the 
Arduino can hold tons of stuff, so serving a page containing 100kbytes 
of Java or similar isn't a problem.  But doing any computation is 
probably not in the picture.



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Re: [time-nuts] web presentation of data

[shalimr9]

Regarding plotting data files through a web page, some time ago I wrote a  
small utility to do just that. We have a corona tester here at my workplace  
that generates binary files with the corona data. These are not easily  
plotted from a standard tool because of the proprietary format.


Instead of writing a Visual something program that would have to be  
installed on all the machines that might need to display the data, I wrote  
a php app that I loaded on the local Linux server.

I also copied it to my ko4bb.com site at http://www.ko4bb.com/graph

You can try it with this file (which you need to download to your local  
hard drive first, so that you can upload it to the tool :)


http://www.ko4bb.com/graph/006.DAT

This software could be easily modified to print any standard file format  
(comma delimited or else) and to adjust the width/height of the picture to  
your liking. Save the picture size in a cookie so that you do not need to  
enter it each time and you are done :)


The source code is there:

http://www.ko4bb.com/graph/index.php.txt

Didier KO4BB

On , John Ackermann N8UR  wrote:
I think there are now a couple of threads going on about this topic,  
which I started by a clumsy attempt to use the "WIDTH" and "HEIGHT"  
attributes in HTML. :-)




For what it's worth, I usually scale web graphics to no larger than 750  
pixels horizontal or 550 pixels vertical. That goes back to the days of  
lower resolution monitors, but still works well with the page layout I  
use at febo.com.




The challenge in this case was that using the default settings in John's  
TimeLab program, I'm getting plots that are about 1350 pixels wide and  
(as PNGs) are ~130kB in size. When down-sampled, it can become difficult  
to read the fine data. The best way to handle that, I think, is to create  
a scaled version of the image and use that as a link to the full-size  
version. Something like:








But that's extra work that I haven't gotten around to automating yet, so  
I thought I'd try using the HTML size options:








The viewer can then right-click on the image and via the "view image" or  
similar menu open up the full-sized version for the fine detail. That  
worked on my browser and monitor, but apparently not on some other  
combinations. So, it's back to the drawing board.




Moving to the second thread on plot generation generally, apart from  
TimeLab I do most of my data capture and analysis in Linux. I typically  
break the two into separate pieces:




1. A single-purpose program (usually written in Perl because I make  
slightly fewer errors with it than other languages) that talks via GPIB  
or serial port and outputs a data file with typically MJD and phase or  
frequency information.




2. A graphing tool that reads the data file. For this, I'm quite fond of  
a program called "Grace" (http://plasma-gate.weizmann.ac.il/Grace/) that  
provides a WYSIWIG graphics interface and saves plot information in an  
ASCII format that's pretty easy to muck around with. Grace is packaged  
with Debian-based Linux distributions; I don't know if there's a Windows  
version available.




I've also done some automatic plot generation to go from data file to  
regularly updated web page. This involves some fairly ugly text  
processing taking advantage of Grace's batch mode, but the result is a  
tool that will read the data file, do whatever statistics are desired,  
combine with the Grace command file, run Grace in batch mode, and create  
an output PNG file that's uploaded to the web. It's actually fairly easy  
to do once you figure out the appropriate black magic...





John









On 8/6/2012 11:34 AM, Jim Lux wrote:




what would be useful is to have some sort of "plotting engine" that is a



canned webpage (or stored locally on the user/client computer) that can



ingest fairly raw data from a URL..





something, conceptually, like this:









*invocation of plotting engine*





data value 1



data value 2



data value 3









that way, a relatively dumb controller (think arduino-ish) could talk to



the instrument and build a web page on the fly without having to do much



formatting. The java/javascript/whathaveyou would do all the plotting



work on the client side (where, presumably, they have a display and some



computational horsepower to drive it)





A low end microcontroller has no problem serving readonly pages from



flash/SD, it just has a tough time doing graphics.







And, if you wanted the raw data, you serve up a page called "raw.html"



or something that just has the raw data.





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To unsubscribe, go to



https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts



and follow the instructions there.








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Re: [time-nuts] web presentation of data

[Bob Bownes]

If you are looking to graph long running data and provide rolled up
summaries, the combination of MRTG and RRDtool is pretty hard to beat. Can
work with pretty much anything on the back end. And it's the industry
standard for network monitoring.

http://oss.oetiker.ch/mrtg/doc/mrtg.en.html

Or some examples:

http://www.switch.ch/network/operation/statistics/geant2.html



On Tue, Aug 7, 2012 at 10:04 AM,  wrote:

> Regarding plotting data files through a web page, some time ago I wrote a
> small utility to do just that. We have a corona tester here at my workplace
> that generates binary files with the corona data. These are not easily
> plotted from a standard tool because of the proprietary format.
>
> Instead of writing a Visual something program that would have to be
> installed on all the machines that might need to display the data, I wrote
> a php app that I loaded on the local Linux server.
> I also copied it to my ko4bb.com site at http://www.ko4bb.com/graph
>
> You can try it with this file (which you need to download to your local
> hard drive first, so that you can upload it to the tool :)
>
> http://www.ko4bb.com/graph/**006.DAT 
>
> This software could be easily modified to print any standard file format
> (comma delimited or else) and to adjust the width/height of the picture to
> your liking. Save the picture size in a cookie so that you do not need to
> enter it each time and you are done :)
>
> The source code is there:
>
> http://www.ko4bb.com/graph/**index.php.txt
>
> Didier KO4BB
>
>
> On , John Ackermann N8UR  wrote:
>
>> I think there are now a couple of threads going on about this topic,
>> which I started by a clumsy attempt to use the "WIDTH" and "HEIGHT"
>> attributes in HTML. :-)
>>
>
>
>
>  For what it's worth, I usually scale web graphics to no larger than 750
>> pixels horizontal or 550 pixels vertical. That goes back to the days of
>> lower resolution monitors, but still works well with the page layout I use
>> at febo.com.
>>
>
>
>
>  The challenge in this case was that using the default settings in John's
>> TimeLab program, I'm getting plots that are about 1350 pixels wide and (as
>> PNGs) are ~130kB in size. When down-sampled, it can become difficult to
>> read the fine data. The best way to handle that, I think, is to create a
>> scaled version of the image and use that as a link to the full-size
>> version. Something like:
>>
>
>
>
>
>
>
>
>  But that's extra work that I haven't gotten around to automating yet, so
>> I thought I'd try using the HTML size options:
>>
>
>
>
>
>
>
>
>  The viewer can then right-click on the image and via the "view image" or
>> similar menu open up the full-sized version for the fine detail. That
>> worked on my browser and monitor, but apparently not on some other
>> combinations. So, it's back to the drawing board.
>>
>
>
>
>  Moving to the second thread on plot generation generally, apart from
>> TimeLab I do most of my data capture and analysis in Linux. I typically
>> break the two into separate pieces:
>>
>
>
>
>  1. A single-purpose program (usually written in Perl because I make
>> slightly fewer errors with it than other languages) that talks via GPIB or
>> serial port and outputs a data file with typically MJD and phase or
>> frequency information.
>>
>
>
>
>  2. A graphing tool that reads the data file. For this, I'm quite fond of
>> a program called "Grace" 
>> (http://plasma-gate.weizmann.**ac.il/Grace/)
>> that provides a WYSIWIG graphics interface and saves plot information in an
>> ASCII format that's pretty easy to muck around with. Grace is packaged with
>> Debian-based Linux distributions; I don't know if there's a Windows version
>> available.
>>
>
>
>
>  I've also done some automatic plot generation to go from data file to
>> regularly updated web page. This involves some fairly ugly text processing
>> taking advantage of Grace's batch mode, but the result is a tool that will
>> read the data file, do whatever statistics are desired, combine with the
>> Grace command file, run Grace in batch mode, and create an output PNG file
>> that's uploaded to the web. It's actually fairly easy to do once you figure
>> out the appropriate black magic...
>>
>
>
>
>  John
>>
>
>  
>>
>
>
>
>  On 8/6/2012 11:34 AM, Jim Lux wrote:
>>
>
>
>  what would be useful is to have some sort of "plotting engine" that is a
>>
>
>  canned webpage (or stored locally on the user/client computer) that can
>>
>
>  ingest fairly raw data from a URL..
>>
>
>
>
>  something, conceptually, like this:
>>
>
>
>
>
>
>
>
>  *invocation of plotting engine*
>>
>
>
>
>  data value 1
>>
>
>  data value 2
>>
>
>  data value 3
>>
>
>
>
>
>
>
>
>  that way, a relatively dumb controller (think arduino-ish) could talk to
>>
>
>  the instrument and build a web page on the fly without having to do much
>>
>
>  formatting. The java/javascript/what

Re: [time-nuts] web presentation of data

[Chris Albertson]

On Tue, Aug 7, 2012 at 6:45 AM, Jim Lux  wrote:

> On 8/6/12 10:43 AM, Chris Albertson wrote:
>
>> On Mon, Aug 6, 2012 at 8:34 AM, Jim Lux  wrote:
>>
>>  what would be useful is to have some sort of "plotting engine" that is a
>>> canned webpage (or stored locally on the user/client computer) that can
>>> ingest fairly raw data from a URL..
>>>
>>> something, conceptually, like this:
>>>
>>>
>>> 
>>> *invocation of plotting engine*
>>>
>>> data value 1
>>> data value 2
>>> data value 3
>>>
>>> 
>>>
>>>
>>>  What you are saying is that the data needs to be rendered to a graphic
>> locally.   I think the simplest way is to create vector based plots on the
>> server (I've used GNU Plot inside a CGI script) but there is a system to
>> pretty much what you are asking for.  http://code.google.com/p/flot/
>>
>>
>
> Somehow, I don't think running Gnuplot on a Arduino is feasible.  ABout
> all it can do is respond to the HTTP "Get" with the right page.
>
> That's why I want to push the hard work of doing the rendering onto the
> client (i.e. the browser).  The comm link is fast, and an SD card on the
> Arduino can hold tons of stuff, so serving a page containing 100kbytes of
> Java or similar isn't a problem.  But doing any computation is probably not
> in the picture.
>
>
So the web server is inside an Arduino?  Yes can't run GNUplot there.   Why
not have the Arduino produce either Postscript or PDF?  It is very easy to
draw a graph in Postscript.  Postscript is just ASCII text that contains
statements like "Draw a line from (2.34,6.65) to (3.45,78.4)" You can draw
using your application's natural units, then you apply a transform to map
those to output units like inches or cm.   Later the web browser or the
printer turns those draw commands into a rasterised image fro display.
 Postscript is very compact.  A few KB would be more than enough for a
graph. The advantage is that the output resolution is "perfect" because
your lines are drawn using natural units with as many places after the
decimal point as you like.   So your users can zoom in if they want to
1000X zoom and see details, not pixels.It wil fet on any screen

Also everyone already has the display engine.  PDF is very much like
Postscript. but I think Postscrip in "EPS" form is easy to create inside an
Arduino,

-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] web presentation of data

[mike cook]

Le 07/08/2012 17:56, Chris Albertson a écrit :

On Tue, Aug 7, 2012 at 6:45 AM, Jim Lux  wrote:


On 8/6/12 10:43 AM, Chris Albertson wrote:


On Mon, Aug 6, 2012 at 8:34 AM, Jim Lux  wrote:

  what would be useful is to have some sort of "plotting engine" that is a

canned webpage (or stored locally on the user/client computer) that can
ingest fairly raw data from a URL..


So the web server is inside an Arduino?  Yes can't run GNUplot there.   Why
not have the Arduino produce either Postscript or PDF?  It is very easy to
draw a graph in Postscript.
  
Also everyone already has the display engine.  PDF is very much like
Postscript. but I think Postscrip in "EPS" form is easy to create inside an
Arduino,

One good reason for doing as little as possible in a micro-controller is 
that they are often used to collect raw  data with as little latency as 
possible. Doing web serving on a single slowish core in that case is not 
a good idea. I have a bunch of Soekris doing data collection and if I 
start to do compute intensive tasks on one, it skews the timing, so I 
use a completely independent one to do the web serving, with the data 
collectors providing access to data via nfs which does not seen to 
impact the timing much even though I can't guarantee that requests are 
satisfied in otherwise idle time . I like the idea of  client side 
graphing. It probably exists already somewhere though I haven't checked 
details - RGraph pops up with google.


--
Les chiens aboient, et la caravane passe.


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Re: [time-nuts] web presentation of data

[Hal Murray]

albertson.ch...@gmail.com said:
> So the web server is inside an Arduino?  Yes can't run GNUplot there.   Why
> not have the Arduino produce either Postscript or PDF?  It is very easy to
> draw a graph in Postscript.

That's a very good suggestion.

I think the key idea is that the programmer is making some high level 
decisions that greatly simplify making the graph.  Once you do that, you 
don't need a complicated graphing program like gnuplot.  An Arduino is smart 
enough to do simple things like scaling once you have the environment setup.


Now that you remind me, I actually did that 20+ years ago.  I'll fish out the 
details if anybody wants to go down that rathole.  The old/early Postscript 
books are very good.

We were collecting loadcell data.  A Mac-SE is probably about as smart as an 
Arduino.  Each data file had a few header lines then a bunch of numbers.  To 
print things, I just cat-ed a postscript program with one or more data files 
and sent it to the printer.  The postscript code was smart enough to read and 
process the data files.



-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] web presentation of data

[Poul-Henning Kamp]

In message <20120807180611.cf5c9800...@ip-64-139-1-69.sjc.megapath.net>, Hal Mu
rray writes:
>
>albertson.ch...@gmail.com said:
>> So the web server is inside an Arduino?  Yes can't run GNUplot there.   Why
>> not have the Arduino produce either Postscript or PDF?  It is very easy to
>> draw a graph in Postscript.

Very few browsers understand postscript.

PDF requires you to keep a context of the entire document.

SVG is like postscript but browsers understand it.

Do a "show source" on this one:

http://phk.freebsd.dk/misc/hp85662_b.svg

It doesn't get any easier than that...


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

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Re: [time-nuts] web presentation of data

[Chris Albertson]

One good reason for doing as little as possible in a micro-controller is
> that they are often used to collect raw  data with as little latency as
> possible. Doing web serving on a single slowish core in that case is not a
> good idea. I have a bunch of Soekris doing data collection and if I start
> to do compute intensive tasks on one, it skews the timing, so I use a
> completely independent one to do the web serving, with the data collectors
> providing access to data via nfs which does not seen to impact the timing
> much even though I can't guarantee that requests are satisfied in otherwise
> idle time . I like the idea of  client side graphing. It probably exists
> already somewhere though I haven't checked details - RGraph pops up with
> google.
>
>
You are right about i being easier to not mix real-time and backround tasks
on a small uP.   But it can be done.  The way to do it is to make the
real-time task interrup driven.  You can use a timer that goes off (say) 50
ties per second and in the handler you do your real-tie data collection or
poll the hardware, read sensors or whatever.  Then in the background task
you run the web server.   This way there is never a chance of something
like network requests slowing down the data collection..A simple two
task "multi-tasker" is easy.  It gets harder when you have more tasks and
I'd fgo with some kind of OS even it that required a larger uP.

That said.  Even if it is easy I'dstill put the web server on a "real"
computer and only pass data out of the arduino.  But it could be done.  I
build a web server (and an FTP server) into a CCD camera and there is no
performance issue at all.  Even during an exposure while reading out the
CCD chip.

As for going the graphics in the client.   That really is easy now that
every client computer has a PDF viewer.  Simply make your graph a PDF
document.

Chris Albertson
Redondo Beach, California
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