[Qgis-user] Problem adding a raster layer from text file

[Craig Leat]

Chris wrote:
> Hi Craig,
>
> Thanks to your precise instructions I've been able to import the data 
> correctly. :-)
> I now have another issue, how to display continuous colors.
> I went to Properties and fiddled with both Graduated Symbol and 
> Continuous Colors. The results appear in the attached pics, and look 
> terrible and useless. I don't want a symbol for each pixel, but a 
> simple color code. An example of what I'm trying to achieve is also 
> attached.
> I also noted that the transparency cursor does not do anything.
> I guess I miss something important here.
> Can you please help?
>
> Thanks,
> Chris

Hi Chris

You are likely to receive better help and a quicker response if you post 
your questions to the mailing list. I'm running hard at the moment, so 
your mail has sat in my inbox for a few days. I've only had a very quick 
look at the images you sent me and these are my first thoughts:

1. The resolution of your sample map (the example of what you are trying 
to achieve) is VERY much higher than the resolution of your data
2. The maps you have created appear to have large areas with the same 
data values. Either there are problems with your source data or you have 
lost precision when creating the map. Did you import float values into 
an integer map?
3. To produce a higher resolution map you may need to use a model like 
r.sun from GRASS and calibrate it against your data (if you are sure 
your data is right!)

Regards

Craig