Re: [GD-DEVEL] plotting data txt array

Hi Bill!

On Jan 23, 2008 12:46 PM, Bill Frost <[email protected]> wrote:
> Hi Pierre et al,
>
> This is exactly what I do with gd but with GPS data. Using C++, I open a
> text file, instantiate a class of moving objects, work out all kinds of max,
> min, average and standard deviation for velocity, altitude, gradient, power,
> time independent altitude profile etc then use a very crude Newton-Raphson
> hack to try and smooth out multipath (ghosting) errors in the GPS reported
> height. Finally I calculate each point's closest approach to a series of
> waypoints and use gd to give me a simple map (lon / lat) and a series of
> pseudo-3D JPEGs showing profile, velocity, gradient and power and known
> waypoints.
>
> I can take a 10,000 point log file and 150 member waypoint file and have it
> all analysed, averaged, summarised and graphed with an HTML interface in
> under 4 seconds. That's C++ and gdLib - not me!
>
> gdLib was the first utility I found that actually did what it should without
> me having to modify undocumented parameters or similar gotchas.
>
> For a little while I've been thinking of making a simple tutorial with C++
> source to take a user through the basics, because it took me awhile to learn
> how to plot to a canvas without wanting to learn matrix manipulation. I
> compromise with a graphClass that calculates the rotation and shadow for
> each point, then graphs it. It has never failed, apart from the bugs in my
> own code.

It is great to read that, it shows that our efforts in the last months
are paying :) I hope you will like our upcoming new features!

> So give me a path on the server and a few weeks. I'll write an article on
> drawing basic graphics, upload some platform-independent source files and
> get others to critique it.

You have an account in the wiki, that means you can create your own
pages and all the related data. You could create a tutorial page in
the documentation? Like "DrawingChart" or something similar :)

About c++, have you noticed the newly added c++ binding from Kevin
Kevin Shepherd?

Cheers,
-- 
Pierre
http://blog.thepimp.net | http://www.libgd.org