[Qgis-user] convert point data to color gradient

[Stephen Leake]

I'm using Qgis 2.2.0-Valmiera 64 bits, on MS Windows 7.

I'm just getting started with Qgis, and GIS in general.

I'm trying to create a map similar to
http://nadp.sws.uiuc.edu/maplib/pdf/mdn/hg_Conc_2011.pdf, with updated
data, and for Kansas only.

I have data in an MS Excel spreadsheet; I can import that to QGIS via a
.csv intermediate.

Now I need to convert that point data into a color gradient. 

I found the algorithm Processing | Toolbox | Models | Example | Contour
lines from points ; that seems like a good first step.

However, when I try to run it, it produces an error message. I can't
read the entire error message, because the window closes.

More precisely:

load the project with the data

double click on Processing | Toolbox | Models | Example | Contour
lines from points

Keep the default selections; in particular, "open output file ..." is
checked.

click Run

An error dialog pops up: title "Problem loading output layers", text
saying "file ... cannot be opened ...".

I can see part of the error message in the "Contour lines from points"
window, but I can't scroll to see the rest.

When I close the error window, the "Contour lines from points" window
also closes.

If I uncheck "open output file ...", the "Contour lines from points"
window closes immediately.

1) Is there a way to keep the algorithm window open after failure, so I
can scroll to see the entire error message?

2) This appears to be running a command line executable in a sub-shell;
how do I find out what that executable is, so I can try to run it
directly?

3) Once I get the contour map, what algorithm will convert it to a color
gradient?

4) Is there a better way?

Thanks,

-- 
-- Stephe