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[Axel Bruns <654030@xxxxxxxxxxxxxxxxxx>]

Mathieu,

many thanks for this again. I think what I'm trying to do is more
complicated than that, though:

First, as far as I can tell, the first approach (transforming numerical
columns into a time interval) doesn't work for nodes or edges which
appear, disappear, and the re-appear - e.g. <[1.0, 10.0); [20.0,
Infinity]> in my example above, which is visible from 1 to 10, and then
again from 20 to the end. I'm not sure whether Gephi allows me to select
four columns (e.g. start1, end1, start2, end2) to convert into one
single time interval - but even that would get very messy in the case of
a node which appears and disappears very frequently over time...

And I've been reluctant to try the GEXF route, mainly because of the
nature of my data: if I understand GEXF slices right (and I may not),
they work only for fairly well-defined and consistent time intervals
(day by day, hour by hour, etc.). However, I'm dealing with continuous
Twitter data which has no clear time intervals - tweets may appear at
random, any second of the timeline, and I don't want to lose too much of
that resolution by defining hour-by-hour slices, for example. Also,
converting my Twitter data (which is in CSV form by default) to GEXF for
import into Gephi would be very work-intensive - being able to import
the CSVs of nodes and edges which I already have would be a lot
easier...;-)

So if there's a way to add functionality in Gephi to activate the Time
Interval column which I can already import, that would be the path of
least resistance for my purposes... I know it's a very obscure request,
but if there's a any way to do it, that would be fantastic !

Axel

-- 
NullPointerException on importing CSV data in Data Laboratory
https://bugs.launchpad.net/bugs/654030
You received this bug notification because you are a member of Gephi
Team, which is subscribed to 0.7.

Status in Gephi - Network exploration and manipulation: Fix Committed
Status in Gephi 0.7 series: Fix Committed

Bug description:


Graph API throws NPE because source or target is null

Stack trace:
java.lang.NullPointerException
	at org.gephi.graph.dhns.core.GraphFactoryImpl.newEdge(GraphFactoryImpl.java:128)
	at org.gephi.graph.dhns.core.GraphFactoryImpl.newEdge(GraphFactoryImpl.java:123)
	at org.gephi.graph.dhns.core.GraphFactoryImpl.newEdge(GraphFactoryImpl.java:47)
	at org.gephi.datalab.impl.GraphElementsControllerImpl.buildEdge(GraphElementsControllerImpl.java:431)
	at org.gephi.datalab.impl.GraphElementsControllerImpl.createEdge(GraphElementsControllerImpl.java:89)
	at org.gephi.datalab.impl.AttributeColumnsControllerImpl.importCSVToEdgesTable(AttributeColumnsControllerImpl.java:597)
	at org.gephi.datalab.plugin.manipulators.general.ui.ImportCSVUIWizardAction.performAction(ImportCSVUIWizardAction.java:85)
	at org.gephi.datalab.plugin.manipulators.general.ImportCSV.execute(ImportCSV.java:40)