I have build a force directed graph for the social network analysis.
The problem which I am facing is that nodes keeps on overlapping each other,
How can I prevent overlapping of node in force directed graph ?
Here is my code with dummy data
And following is the image for my force directed graph
How can I remove overlapping of these nodes ? and how can I keep atleast some distance between links so that links are properly visible ?
There are two approaches to avoiding overlap in a d3 force layout.
The first is to adjust the parameters of the force object, the most relevant of which is the "charge" parameter. Nodes with negative "charge" values push other nodes away (versus nodes with positive values pull other nodes closer), and you can increase the amount of charge to cause a greater push.
The default value for the "charge" is -30, so from there you can adjust it until you get an effect you want. There's no simple formula for determining the value you want, since it also depends on the other parameters and the amount of links in your graph.
If for any reason adjusting the charge doesn't work for you (for example, if you want the nodes to cluster close to each other -- not repel each other -- but still not overlap), then you can manually check for overlapping nodes, as in this Mike Bostock example suggested by Josh in the comments.
Related
I want to use amcharts4 to display a network with a huge number of parent nodes and even more child nodes. I took one of the examples found on the amcharts website and increased the number of child nodes on multiple parent nodes. The nodes expand to a point where they bounce off the browser screen and become unreachable. I am a looking for a way to navigate the network by zooming and panning in order to reach the nodes that are outside of the browser page.
I found similar questions on stackoverflow but they were mainly related with XYCharts and maps where ZoomControl was used on the chart/map object and the zoom property was enabled. I couldn't use this method on the force directed diagram element that I have in my code.
Kindly help me out if you know of a way to navigate the force directed diagram either by mouse wheel scrolling and clicking to pan or using the keyboard. Any help is appreciated.
networkSeries.maxLevels = 1; is the only thing I could think of as I did not come across anything that lets you navigate or pan force-directed graphs.maxLevels will reduce the space occupied but it still doesn't answer the question
I would like to create a force directed graph, but i need it to stay the same every time it is generated (with the same data).
Is there any way to do this using d3.js?
UPDATE:
I found working solution, which is based on using seeded random number generator
// set the random seed
Math.seedrandom('mySeed');
You could by modifying D3's force layout, or by creating your own layout based on it. There are at least 3 places where randomness (Math.Random) is used in the positioning of nodes (there may be more, given the force layout references other code). You would have to eliminate all randomness in order to get the graph to display in the same way each time:
https://github.com/mbostock/d3/blob/master/src/layout/force.js
However, this would hamper how the layout works – it's using randomness to sort itself out into a legible diagram quickly. If your number of nodes is small, then it probably wouldn't be an issue, but a large number of nodes could just end up a tangle.
I'm developing a complex horizontal tree graph with d3 and the d3.layout.tree() function. Now I'm in a point where I need to display a list in each node with a fixed depth (e.g. 4), and these lists have variable height.
One way to manage this is to set a chart height so no nodes get overlapped, but I have to consider the case that all the nodes have the longest list. This makes the chart extremely long and visually ugly, so I wonder if it is a way to set the vertical distance between the horizontal branches dynamically.
I've tried the nodeSize property but again, it has to be the same for all the nodes. If there is no possible way to do this, how would you tackle this problem? I've already set a modal to show all the information, but these lists are mandatory and have to be in the tree chart.
Thanks
Good morning,
just starting with the awesome d3js library ...
I want to show only a portion of a graph with the force directed layout. The idea is to have one node declared as the "center" and show all nodes within a distance of two (for example) from this center node, the neighbors of the center node and the neighbors of the neighbors. If the user clicks on one of the displayed nodes it becomes the "new" center node and a different "subgraph" is displayed. I wonder if there is an example around implementing this kind of subgraph layout and if some kind of a "node-distance" algorithm is already implemented in d3js.
Thanks a lot
martin
UPDATE:
Just found the example Modifying a Force Layout which illuminates how to add and remove nodes and edges from a force directed layout.
I just uploaded a "proof of concept level" of an interactive force directed subgraph.
http://justdharma.com/d3/sub-graph/
In this example I use backbonejs under the hood. Being the first time I implement something with backbonejs, I for sure use it in a very crude manner. While this example might illuminate one way how an interactive sub-graph can be achieved it is for sure not a template how to do it - as said just a proof of concept hack ...
This isn't implemented in D3, and I'm not aware of any examples. What you would have to do is the following:
Set the fixed attribute of the new center node to true to prevent the force layout from changing its position.
Set the px and py attributes of that same node to the center position.
For each node in your force layout, compute the shortest path to the new center node.
Depending on the length of the path in each case, either remove the node or keep it.
The trickiest part here is the computation of the path from each node to the new center, but even this is a pretty standard algorithmic problem. Another thing to keep in mind is that you need to modify the data structures that contain the nodes and links of the force layout in place, i.e. you can't set new nodes and links for the force layout and expect everything to work smoothly.
So currently I'm trying to create a force-directed graph of a couple thousand nodes and about 30k links in the graph. As you may guess, the simulation is very very slow. What I would like to do instead is to precompute all the positions for the nodes and just render a static (but interactive) graph. Is there a way to use d3.js to calculate a force directed graph without rendering it (making it much faster) and then just render the static graph from the pre-calculated values? My code is currently based off Mike Bostock's example.
The method d3 uses for force directed graph layout is the standard repulsive force and attractive force model, you can find the pseudo code on Wikipedia (http://en.wikipedia.org/wiki/Force-based_algorithms_%28graph_drawing%29#Pseudocode) or check out the d3 source itself (https://github.com/mbostock/d3/blob/master/src/layout/force.js).
That algorithm has an O(n^2) complexity per tick (or time slice) and it takes about n ticks to reach an equilibrium so O(n^3) for the whole layout process (http://www.ecs.umass.edu/ece/labs/vlsicad/ece665/presentations/Force-Directed-Adel.ppt). For thousands of nodes this isn't practical.
To try and answer your specific question, just use CSS, display: none on your SVG container element. Once the initial simulation "eventually" finishes you can grab the HTML source of the SVG elements and use that as your basis for the static but interactive representation. (once you have html of all the elements you'd just have to add the mouse hover event onto them to have them display their details.