Label individual points in Sage plot - plot

This seems like a straightforward problem, yet I can't find a solution. In Sage, I've got about 30 sorted points for a scatter_plot, and I want to add the order position as a label. I know this is easy if I were working with a graph object, since I could use the vertex_labels option in plot. Is there a simple fix to get this to work for a scatter_plot, or would I need to do something like make the points vertices and keep track of the exact location of each point

Currently, you may have to use matplotlib directly or mess around with that method inside of Sage to get this. See here or here for some related questions.
I've opened Trac 20583 for this.

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External node color in Gephi

I'm trying to create a graph in Gephi. This graph is undirected and has over 100 nodes. I would like to color the nodes in this graph according to my convenience. Say I'd like to color the nodes in 9 different colors. For doing this, I downloaded a plugin to Gephi which may be found here.
Though the plugin works, I still have to go and enter the color value for every single node manually. There doesn't seem to be a way to do this programatically. And I'd have to create about 10 such graphs, so that means a lot of manual labor.
Can someone help me out with this problem? Does someone know a better way to have custom colors for each node generated programatically? At this point, I'm generating a .gdf file, the format looks something like this.
I also know that Gephi is quite buggy, is there any other graph visualization software that I can use? Out of the other usual things that one does to the graph, I definitely want the capability to set edge weights. In other words, I'd like to make the edges thicker if the edge weight is more and vice-versa.
I can't use D3 coz I don't know Javascript. I looked into using GraphViz but it seems like it requires a lot of manual manipulation of the graph file. I'd like to have something that I'm able to generate programatically.
What seems to be working is to add a column named color VARCHAR where you add the color hex value prepended with the # sign and no quotes.
Example:
nodedef> name,label,color VARCHAR
a,"Apple",#00ffdd
b,"Banana",#00ddff
c,"Cherry",#dd00ff
d,"Did it!",#0012ca
e,"Ed 209",#121212
edgedef> node1,node2,weight
a,b,2
b,c,30
b,d,0.4
d,e,200
Edit:
For a more informed answer take a look at the Gephi documentation. The color values in the link are rgb triples but I tried with hex and it worked

Creating a grid on a map in R using grid points

I'm clearly struggling with this problem for a day now and can't seem to find a nice solution to it. I would really appreciate some help and I'm really a novice in R (since last week).
Problem 1:
I have a set CSV representing grid points which I can parse into a data frame (pointname, latitude, longitude).
Eg:
name,latitude,longitude
x0y0,35.9767,-122.605
x1y0,35.9767,-122.594
x2y0,35.9767,-122.583
x0y1,35.9857,-122.605
x1y1,35.9857,-122.594
x2y1,35.9857,-122.583
x0y2,35.9947,-122.605
x1y2,35.9947,-122.594
x2y2,35.9947,-122.583
The points in this file represent the lower left corner and are arranged in row major format, meaning lowest horizontal grid points first. Each point is a certain great circle distance away from its neighbors (1km). I want to create a grid overlay on a map which I've plotted using ggmap.
What I've tried or considered:
map.grid() - this is really not useful to me as I'm not looking for any kind of projection.
geom_vline() and geom_hline(). These look good but I don't have constant x and y intercepts on a plane. Moreover, once I create a grid, I'd like to use the grid to color against a density.
geom_rect() and geom_tile(). These look really promising and may be what I want. But I'm not able to find a good way of working with these.
I'd like to fill these grid boxes later with another parameter. Any suggestions on how I can create such a grid? This may be a trivial question but I don't know a lot of R yet.
Problem 2:
How can I store or hold such a grid so that I given a point (lat,lon), I can quickly get to that grid. In fact my whole back end is in C++ and can directly output the grid name x<n>y<n> directly against a given search point. I somehow am finding it difficult to count such points against grid points so that I can fill grid with a representative color.
I'm not sure if everything of what I'm saying is clear. Please tell me if I've to clarify something.
Also note that I've Googled quite a lot and not found relevant answers although some looked close.
Eg: This, ThisToo
Thanks for the help!

How to plot magnetic field lines in mathematica?

I am preparing for the exams, and I have spent couple of days trying to solve the task, but without success. Can someone show me how I solve this? The result should look like this:
You can use StreamPlot or VectorPlot
for 3D fields, there is no built-in command. However, you can use VectorPlot3D.
There is also a 3rd party code for 3D streamline plot that you can find here.

How to set minimum for Jenkins Plot Plugin

I use Jenkins and its Plot Plugin to generate statistics.
Example:
For every Build I plot the line of codes. Lets say I have like 500.000 lines and it changes about +-100 lines per build.
Since the plot y-axis always starts with 0 the whole plot is meaningless. It looks like 1 straight line.
Same goes for other metrics, if the value is too high.
Question: is there any configuration to set minimum y-axes to the minimum value?
Unfortunately, I think the answer to your question is currently 'no'.
First of all, the documentation does not give any hints towards such an option.
Secondly, Given that the Jenkins Plot Plugin uses JFreeChart for the plotting, the setting of a range for the Y-axis should be done using the 'getRangeAxis' function. A search in the source-code does not reveal a call to this function.
Lastly, you do not seem to be the only one that has this problem. Issue JENKINS-2841 asks for the same functionality, but appears not be solved yet.

How to draw a line or select something in using qvtkwidget?

I successfully made a program by using qvtkwidget, showing a few lines and points. And everything works perfectly. Next, I want to add an edit mode to my program, so that I can draw a line on it, or select some points or lines from it. Could anyone give me some guidelines for doing that? Do I need to use vtkRenderWindowInteractor? I tried to google but still can't find any clue.
you have to work with vtkinteraction, vtkobserver- callback, and vtkselection modules. and this example also useful http://www.vtk.org/Wiki/VTK/Examples/Cxx/Interaction/MoveAVertex HTH
And here is set of examples you may find relavent to your goal
http://www.vtk.org/Wiki/VTK/Examples/Cxx#User_Interaction

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