[Qgis-us-user] Data plotting problem, bug?

Wilkes, Becky bwilkes at email.unc.edu
Wed Jan 13 06:18:17 PST 2016

I have had problems with the classing algorithm in QGIS in the past.  I think the problem is that the classes overlap, and there is some kind of rounding error.  If you can manually change the breaks to something like this, it might help:
1     .44-.45
2     .46-.64
3     .65-.75


Becky Wilkes, GISP
Cartography, spatial data vizualization
MEASURE Evaluation<http://www.measureevaluation.org/>, a USAID-funded global health project
CPC, University of North Carolina at Chapel Hill

Office  919-445-9323 | Cell  919-604-1152 | Skype  wilkes.becky
Twitter  @wilkes_becky<http://twitter.com/wilkes_becky>  |  LinkedIn  wilkesbecky<http://www.linkedin.com/in/wilkesbecky>

From: Qgis-us-user [mailto:qgis-us-user-bounces at lists.osgeo.org] On Behalf Of James Keener
Sent: Tuesday, January 12, 2016 3:39 PM
To: Patty Rehn <quicksilversystems at gmail.com>
Cc: qgis-us-user at lists.osgeo.org
Subject: Re: [Qgis-us-user] Data plotting problem, bug?

Internal question: That's weird that the start and end values overlap. What are the rules for this when it's deriving them?

Can you try making the groups not overlap? I'm curious if some code makes the ranges inclusive and others exclusive?


On Tue, Jan 12, 2016 at 3:36 PM, Patty Rehn <quicksilversystems at gmail.com<mailto:quicksilversystems at gmail.com>> wrote:
Hi everyone,
Sorry if this is duplicate post, since I posted it to other places but got no response, so trying here too.

For QGIS 2.10.1 Pisa, Win8
I am attempting to plot my data (about 50 points, imported csv, converted to shape file);
 as graduated by size, divided by natural breaks, 8 classes, link class boundaries, simple circle markers

The problem is one point will not plot, unless the class is only that point (class 1):

1     .449872-.449872
2     .449872-.649973
3     .648873-.749909
The point should plot with class 2 but does not.
If I delete class 1, the point goes away.
I have tried tweaking the class values such that the value should be included in
class 2 also, but no difference.
The circles are sized with the lowest values as the largest circles, if that matters.

Additionally, sometimes the “show feature count” function gives the
correct number of feature in the class but other times, it only lists zeros.
Thank you for your suggestions.

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