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Overlapping nodes - how to position nodes along z-coordinate

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Overlapping nodes - how to position nodes along z-coordinate

Postby sbodenmann » 17 Oct 2013 01:06

Hello everyone,

I'm trying to render a network of correspondences composed of more than 250 single correspondents (and growing). I would like to visualize the number of correspondents per cities. To this end, I went through the following steps:

(1) I gave all my nodes (correspondents) three atributes: location (String: for example Berlin); longitude; latitude.

(2) I applied the Geo Layout

(3) I grouped and labeled the nodes by their respective location (Berlin, London, Paris, ...)

So far so good... but now begins the problems:

Some cities are extremly close to each other (for example London and Oxford or Berlin and Potsdam). Because a lot of correspondents are sending their letters from Berlin, the ones living and writing from Potsdam are completly hidden by the huge group of nodes in Berlin.


can I change the order of displaying the nodes or more precisely: can I let the smaller Potsdam group appear in the foreground uppon the much larger Berlin group?

Failed to find a solution

My first idea was to modify the z-coordinates of the nodes but I experienced two problems:

(a) changing the z-coordinate from 0 (standard) to 1 provokes the node to actually move along x and y!!! sometimes the node also changes its size, becoming bigger and bigger with each iterations of z. It seems to be a projection problem, because if I zoom-in, the relative positions of the nodes will change much like the old microsoft windows stars screensaver. Is there a way to force an orthogonal projection in the overview tab?

(b) only a big value for z (>800) make the node effectively appears above a node with a z-coordinate value of 0! I can't understand why!

(c) All this occurs only in the overview tab. In the preview tab (despite updating the drawing of the nodes) nothing is happening at all.

To illustrate this, I inserted some screenshots.

On June 2012, user sfranky reported similar problems in a post entitled "x,y,z of nodes not displayed properly?" http://forum.gephi.org/viewtopic.php?f=5&t=1923. But he never received any answers.

I would really appreciate any help in this matter. Thank you so much!

S. Bodenmann
screenshots of the problems described
Posts: 5
Joined: 08 Aug 2013 16:07

Re: Overlapping nodes - how to position nodes along z-coordi

Postby sbodenmann » 17 Oct 2013 01:19

To give an idea of the result I'm expecting, I add an example found in Sigrist, René, "Les communautés savantes européennes à la fin du XVIIIe siècle - essai de cartographie", in: M@ppemonde 110 (2013:2), p. 9 [http://mappemonde.mgm.fr/num38/articles/art13204.html]
Posts: 5
Joined: 08 Aug 2013 16:07

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