Tikz is a nice LaTeX package for easily drawing diagrams. Diagrams are made by putting code directly into the TeX document, eliminating the need for extra image files. The package also is very powerful and versatile; the manual contains a very detailed description of its features.

Asymptote is my tool of choice for virtually any mathematics diagram, geometry included.

Mathematica

Geometer's Sketchpad— Sketchpad 5 exports/copy-pastes diagrams much better than 4 did.

I have been enjoying kseg. It is very quick to draw diagrams in kseg.

After you draw the diagram you can drag the components around and the others will follow, retaining the same constraints. For example, in this diagram it appears that $NM$ is the perpendicular bisector of $PQ$:

And I can see if that still appears to be the case even after I move point $C$ to make a very different inscribed quadrilateral:

kseg also lets you define complicated loci, but I haven't tried that yet.

One of the best is WinGCLC.

Graph quality is really exceptional, it's easy to use, can be easily exported to SVG/EPS/BMP/LaTeX, supports command line for scripting, supports animation...

What is really useful is that once you define all the points/lines/intersections/circles, you can easily change the location of one of the starting objects and the whole diagram will be accurately redrawn.

Adobe Illustrator

LaTeXDraw is a graphical front end for PSTricks.

Inkscape is a popular open source drawing package. One feature that makes it particularly nice for drawing mathematical diagrams is that you can easily insert LaTeX output in your drawings.

Metapost. There are a few packages to simplify drawing geometry drawings.

These are my choices:

• Interactive software: Ipe produces postscript and pdf files, can include LaTeX labels and other text, and has helpful snapping modes.




• Non-interactive: Eukleides lets you design pretty high quality geometry diagrams with a simple language.

If you are a mathematician and wants to use such pictures for your notes or presentations using TeX files, use the pstricks package enhanced for use of easy by the package LaTeXdraw.

Then there is a very useful linux program called xfig.

Live Geometry for Windows users.

I use the programme CaRMetal. Here are a few screenshots:

http://i34.tinypic.com/2vwcits.jpg

http://i35.tinypic.com/oa42ts.jpg

http://i35.tinypic.com/2lxfin8.jpg

http://i35.tinypic.com/rble9l.jpg

I guess most geometric constructions programmes are good, although I wouldn't recommend Kig.

The free version of Cinderella is in some cases also a good choice.

Geometry is a pretty new app on Mac OS X for making geometric constructions and check angles etc. Contrarily to Latex or others, you can move points and lines etc interactively and see how the drawing evolves based on the construction constraints.

I like that this app is lightweight, with easy keyboard shortcuts, and that it is associated with a website that proposes a few good geometry exercises too. Totally worth its price!

I've used Smile by Satimage on my Mac. (Not SmileLab, just the free Smile. And not to be confused with PDF utility company "Smile on My Mac")

Smile uses AppleScript for drawing. Some example files show an amazing facility for geometric drawings: named points, marked angles, primitives for things like barycenter and circumcenter, TeX-styled labels, etc. A fully-labeled illustration of the Euler Circle can be created with a few lines of script. Outputs to PDF, JPG, etc.

I always have lots of trouble navigating the online documentation, so I know I'm not getting the full benefit of the program. Nevertheless, the ability to describe a drawing precisely with a script is what I need, and it's what the app delivers.

gnuplot

Features

I used gnuplot (official website), which is open source and can produce a huge number of different file types. For instance, you can also output tikz-code if you want to work with LaTeX. It is used for plotting datasets and one can plot easily errorbars.

Installation

You can download it from sourceforge or from your package database if you are using a linux distribution.

I think Geo-Gabra is easy to use.I used is just about 3 months. it is very easy for mathematical drawing.
Download Here;

Geo-Gabra 4.4

If you are referring to geometric sketch, I like to use Dr. Geo, a free software of mine. It is an interactive geometry and programming software. You can make very easily construction with the mouse or more complex iterative one with its programming API.

Interactive geometric sketch designed with mouse and clic

tkz-euclide is a package for embedding, into Tex, drawings of Euclidean constructions. That is, it supplies commands to draw straight lines and circles but nothing any more sophisticated e.g. ellipses or the graphs of arbitrary functions. It also provides commands to locate the points at which one straight line or circle cuts another. (With TikZ, if you wanted to use the intersection points, you'd have to work out their coordinates for yourself.)

It is a layer on top of TikZ. Currently, the only documentation is in French, but it contains numerous examples, so it is quite easy to follow even if you don't understand French.

Desmos Graphing Calculator, is, yes a graphing calculator, but it is also really useful for geometric drawing.

On their homepage they illustrate several examples of how versatile the tool is for drawing. The main drawback of the program is that you need to know the algebraic (Cartesian, Parametric, or Polar) equations behind your shape to draw it.

On the flip side however, that means your drawings are truly accurate; and, furthermore, it is not too difficult to draw everything imagine-able using parametric equations. (You can of course, superimpose multiple equations with one another to draw pictures).

As of 2018, Desmos has released a geometry tool typically for drawing geometry diagrams. That means, using Desmos to draw diagrams no longer requires too much mathematical background. It was a huge improvement.

Microsoft Excel. Just paste x and y (or long and lat) as a table and create a scatter (XY) chart from it.