How to manage drawing illustrations in technical documentation (report, survey, etc)?

Could anybody hints me on how to draw these kinds of illustrations? I am always not confident of creating and combing those small pieces like computers, cables, laptops, sensors, and so on. Especially I want them all to look well-fitting.

And if I want to search the raw material of the pieces of the illustration, what is the keyword for them? Icon? Small gallery? Illustration picture?...

At last, what is the better tool for drawing illustrations, gimp or coreldraw?

Thanks very very much for you help!

I'm 100% sure what you're asking here, but I think what you're looking for is something akin to Visio? If so, there's several really good apps out there, most notably Dia and Kivio. I think what you're looking for are called Stencils, there's a lot available for Dia that Kivio can import, and there's a few available for Kivio that are free. If you're willing to pay, you can get a ton of stencils for just about anything you need for Kivio. You can see them here.

Both of these programs export to several different formats that can then be pasted into any document, be it OpenOffice or a PDF.

Or are you looking for something more CAD like?

Jeremy

Yea a good cad-like app for linux would be, BLENDER, very nice app, has a steep learning curve BTW so be prepared.

Yes, they, stencils, are what I am looking for. Thanks a lot!

But I worry about the quality of the stencils from kivio. Or I am not sure what the effection will be after they are generated by kivio to PDF and openoffice files. One positive example shown as below:
http://users.tkk.fi/~hzhang2/1.jpg

Then, what are CAD-like (stencils OR else)? Could you show me an example or a site link? I am really a newbie in graphic world. Thanks again!

The glory of these programs is that they are vector based and can be resized without the worry of pixelation. However, once you export them to a non-vector format, they will suffer pixelation like any other image.

The CAD versions are much more "technical" looking, if you will, and the interface is incredibly difficult to gain a significant handle on for a newb. I'd stick with Kivio for now. That being said, here's some CAD symbols.

How about posting back when you've got your drawings done so we can check them out?
Jeremy

Try inkskape, its a vector image program (lines, squares, shapes, stencils etc), unlike gimp which deals with raster files (bitmaps, pixels and the like).