Plotting vectors problem; PRIOR: Problem using SGT library / Java / ...

[Damir Dezeljin <programing@nib.si>]

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Message from the sgt mail list.
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Dear colleagues.

Fist excuse my poor English :)

I'm engaged in programming some applets/applications that will output 
oceanographic data. We get raw measured data from our oceanographic buoy 
in Gulf of Trieste (http://boja.msp.nib.si/ for more info), and then we 
compute the values we want to show on internet and than display them.

Prior upgrading our buoy, we used matlab to do images of our computations 
(old images can be found at http://boja.msp.nib.si/kafe/clani/ (you can 
register for a free user/pass or just use my u: dezo/p: korte).
I already port the scalar plot to Java 
(http://www.dezo.org/FileStore/Plot/demo/ - it gets its data from 
http://www.dezo.org/FileStore/Plot/demo/data.txt ... source file is 
available on http://www.dezo.org/FileStore/Plot/sources/).
There I encountered the first problem. I can't print my applet from e.g. 
MS IE (prior upgrading JVM to SUN JVM, I can print applets which was 
caused by but MS JVM which permit accessing printer from web browser ... 
the downside of MS JVM is that it supports Java 1.1 only so I have to 
upgrade). I solve the problem as follows:
- I update my applet so that it can run as stand-alone application which 
display a new button 'Print' which print the graph (e.g. 
http://www.dezo.org/FileStore/Plot/demo/dezo.jar - 'java dezo.jar 
mbp.ScalarPlot');
- I made some investigation in signing .jar files ... For this I have to 
purchase a certificate from CA or set-up my own CA and than distribute my 
CA's public key (I will do this for the last one, because I already 
implemented a workaround)
Any other suggestion how to solve this problem?

Now I want to port our feather plot (vector plot) to java (e.g. of a 
feather plot can be found at: 
http://www.dezo.org/FileStore/Plot/images/VectorPlot.jpg). I encountered 
there some problems:
- I'm very confused by JVectorDemo.java found at SGT homepage ... I found 
that it is using a JPlorLayout to output vectors. There are some things I 
don't understand:
 1. What is VectorCartesianRenderer class meant to be?
 2. How can I output all the vectors only on one line (see below) - for 
example of such a plot, please check feather plot above.
 3. SGTVector(uComp, vComp) accepts two set of data. For e.g. for 
Cartesian plots the fist one is the N component of the vector and the 
second one the E component, but why those data contains also more 
components (ex. JVectorDemo.java)? And how can I specify where to be the 
beginning of the vector (Y=0, X='time_of_mesurement') and what is the 
'vector power' - the length and the direction of the vector?
 4. Is there any other way to output vector plots (like 
CartesianGraph(String) class - in this way I can call c = new 
CartesianGraph("Blah"); c.addXAxis(TimeAxis); c.addYAxis(PlainAxis); 
c.setData(MyData); << like in my ScalarPlot.java ?
 5. Is there any other available Vector plot example source?

I have some other questions:
- Is it interesting to add my sample code to the SGT sources so other 
people can easly start using SGT?
- Are there any recommendations for the file format of the data containing 
oceanographic measurements (we will make our data publicly available)?
- FROM Donald's replay:
> For the applet (remember you need jdk1.2 or newer!), the code
> attribute shouldn't include the class designator  code="ScalarPlot" .
> You may need to download the applet plug-in converter tool from sun,
> called HtmlConverter.
> It will translate your applet code to work with the plug-in.
What is this tool used for - I search the SUN homepage but I don't found 
it (I will recheck for it later)?

Regards,
Dezo


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