[Qgis-user] Classification uses full range of values from joined attribute table

[Lee Hachadoorian]

I am joining a spatial layer (from PostGIS) with an attribute (aspatial)
table (also from PostGIS). There are more rows in the attribute table than
in the spatial table. After I do the join, I open the attribute, and it
only displays rows in the spatial table (i.e., this is an INNER JOIN, or
maybe a LEFT JOIN, I didn't test tables with unmatched attribute rows. The
point being, there are no attribute rows with unmatched rows from the
spatial table).

But when I style the layer, if I choose one of the columns from the joined
attribute table and classify the values (I was using graduated symbology
for a numeric field), the classes that are produced are based on the entire
range of values from the attribute table, i.e., the classification is not
honoring the fact that the join result omits many of the rows from the
attribute table. Since, in the case I tested, the field values for those
rows which match features in the spatial layer only cover a small part of
the total range, the resulting map has all the features falling into fewer
classes than specified (e.g., there are 5 classes in the data, but only 2
colors on the map).

First, I should ask whether I am doing anything wrong here, or if people
can confirm this behavior. Second, I cannot find a specific feature request
related to this at hub.qgis.org, so is this already an tracked issue that I
just wasn't able to find? Third, do others agree that this is unexpected
behavior?

Best,
--Lee


-- 
Lee Hachadoorian
Asst Professor of Geography, Dartmouth College
http://geospatial.commons.gc.cuny.edu/<http://freecity.commons.gc.cuny.edu/>
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