Develop Reference

Plot vertex as image in Igraph

I'm wondering if it is possible to plot a vertex as image (loaded from a file or directly) in Igraph. Any ideas?

This is definitley possible in the R version of iGraph using the raster function, however a brief search did not reveal any implementation of this function in Python (it's not in the igraph documentation anyway).
If this is essential to your work, then I would consider switching to R, or possibly another tool such as Gephi. For Python, however, you might consider using something like pyvis. This package is small but powerful in terms of visualization. I've been playing around with it over the past few days and its very easy to display a graph with pictures as nodes, and it comes with the added benefit of providing interactive functioning. Take a look at the tutorial here, which will highlight what this package can provide.

Generating Network graph in python

I am trying to generate a network graph for 200+ nodes and 300+ edges using networkx using python from a file. I was able to generate and plot the graph using matplotlib in my Juypter Notebook, but its not looking good and nodes are so tightly packed.
Is there any other python package help to generate network graph ??.
My aim is to generate graph for whole data set so that I can find dependency between nodes.

If nodes being too close together is the issue, try using the draw_spring()function of networkx.
https://networkx.github.io/documentation/networkx-2.0/reference/generated/networkx.drawing.nx_pylab.draw_spring.html#networkx.drawing.nx_pylab.draw_spring
It simulates what would happen if each edge were a spring and the network were picked up and spun around, seperating the nodes, especially the ones which are not connected via many paths.
If this does not work initially, you can use the parameters of the function that draw_spring() wraps, the spring_layout() function. Try adjusting the k value parameter. This should allow you to manipulate the rough distance between nodes.
https://networkx.github.io/documentation/networkx-2.0/reference/generated/networkx.drawing.layout.spring_layout.html#networkx.drawing.layout.spring_layout
Alternatively, there are additional draw functions you might find more useful than draw_spring(). You can find them in the draw section here: https://networkx.github.io/documentation/networkx-2.0/reference/drawing.html

I can recommend using Netwulf. Input a networkx.Graph object to netwulf.visualize, and launch the visualization in a new browser window. The result and data can be posted back to Python.
Disclaimer: I co-author Netwulf.

Directed graph in python

I am trying to depict the relationship of different data entities with my ETL (extraction transformation loading) pipeline. The final output is a large directed graph. So far I am using Python to extract data relationship. Pydot helps me generate svg file which I can open up using a browser. The graph that I generate is static.
Pydot lets me setup tooltip and allows me to link other html pages with nodes or edges. I am looking for more than that.
A small portion of the graph is shown below
I want to do several things with this graph.
Every node can have several attributes (including name). It is not possible for me to display those attributes because of paucity of space. But as users mouse over (or do other mouse based action) I would like those attributes to show up as "floating" table which user can dismiss if not interested.
Not all node attributes are integer or strings. It can be graphs as well. For example for one of the nodes I may have a bar chart showing how often this data entity is getting loaded in last 7 days. I would like that bar chart to float over as the user moves (clicks) mouse over that node. Currently I am using matplotlib to generate bar / pie charts associated (please see above) with nodes. I link those diagrams with my original directed graph using setURL in pydot. But the user experience is not great since it takes user over to a new page.
I am happy with node layout etc that I get by default from Pydot/GraphViz. I prefer not to do everything from ground up unless it is absolutely necessary.
Ability to highlight only certain part of the graph based on query in node or edge attributes
I read this forum and came across several options in response to questions similar to mine.
gephi
igraph (I played around with igraph which lets me query by vertex
or edge. I couldn't figure out how I can make my final graph
interactive based on user input e.g. floating table on mouse over of
a node etc)
Javascript libraries - sigma.js, arbor.js, d3.js nodebox
networkX
nodebox
I have Python skill but quite novice on Javascript side. I would like to know from experts what can be my best bet (from functionality and ease of use point of view). A browser based solution is preferred.
Any suggestion / help will be really appreciated.
Thanks
Abhijit

Try NetworkX. Node attributes can be anything hashable, so that addresses (at least) your first two bullets.
You will still be using matplotlib to generate the charts. I don't know of a better solution than that.

What would you use to create an interactive geometry program with python?

What libraries/modules would you recommend for creating an interactive geometry program?
What I have found includes: Pyglet, Pygame, Pycairo, Sympy
I'll illustrate the basic requirements with an example:
Create two Point objects by clicking two locations on a canvas.
Create two intersecting Circle objects based on those two Points.
Detect the two circles and calculate their intersections.
I would like to work with a canvas that supports anti-aliasing.
I would also like the ability to produce(export) an image with a transparent background.

If you have a bit of experience with OpenGL I would seriously recommend pyglet. Very customizable. If you don't, get it, because in Python there doesn't really exist a game/rendering library that has a "canvas-style" interface, except, to a certain point, pygame. But pygame...
Stay away from pygame. Stay away. pygame has horrendous design, documentation, code written with it and performance.
I have no experience with the two others (or any others, for that fact). There aren't many options for this domain in Python sadly (this also is the reason why I started a project like this, but it's still too unstable and WIP). Most notably the built-in support for things like anti-aliasing, primitives and intersection calculating is non-existent.

I have created a library for interactive geometry board using tkinter.
http://bitbucket.org/zambu/pygraph

Tool to create a python GUI for graph construction

I need to create a GUI for graph construction ("graph" as an abstract representation of a set of objects, not a visual representation of data). The interface will provide a choice of ~5 vertex types and of ~5 edge types. Each vertex will have two data fields: a text label and a file name, which need to be easily editable.
I'm familiar with igraph and have a lot of code written in it. I will use igraph to manipulate the graphs created with this GUI.
Since this will be my first GUI, I'm completely ignorant of what tools are available. Can you please suggest a free library, knowing that eventually the program will need to work on Windows?
EDIT
it seems from the answers I get that I wasn't clear enough. I'm not looking for a way to visualize a graph, but rather for a way to visually create one. By visually, I mean not needing to manually create text files or writing code.

Take a look at xdot.py.
From the homepage
xdot.py is an interactive viewer for graphs written in Graphviz's
dot language.
It uses internally the graphviz's xdot output format as an
intermediate format, and PyGTK and Cairo for rendering.
xdot.py can be used either as a standalone application from
command line, or as a library embedded in your python application.

I like networkx,
from networkx import draw, Graph
from pylab import show
g = Graph()
g.add_edges_from([(1,2),(1,3),(2,4),(2,5)])
draw(g)
show()
which gives,
The only quirk is the requirement for matplotlib to get builtin plotting to work.

If you use python, I think PyQt is a good selection.
What you have to install is listed below:
install Python from here
install PyQt4 from here
But it takes many lines to write GUI application,
it is sometimes better to generate an image to display with image viewer.