[R-sig-Geo] help: krigged map do not show colours

Anand Sookun asookun at gmail.com
Tue Aug 4 15:33:39 CEST 2015


DearJon

Thnaks. I will try that soon.

Cheers

Anand

On Tue, Aug 4, 2015 at 4:55 PM, Jon Skoien <jon.skoien at jrc.ec.europa.eu>
wrote:

> Anand,
>
> I could not open your .grd file in R, I think the .gri file is missing.
> However, looking at it in a text editor, and comparing with your R-script,
> it seems something went wrong with your projections. Your .csv-file has
> LatLong coordinates, but you are setting the projection to "+proj=utm
> +zone=40 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84
> +towgs84=0,0,0", the same as you seem to have in your prediction raster.
> But you need to reproject your observations in this case.
>
> # First set the right projection:
> proj4string(carbon_seq) <- CRS("+init=epsg4326") # epsg-code for latlong
> # Then transform
> carbon_seq = spTransform(carbon_seq, CRS("+proj=utm +zone=40 +south
> +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0"))
>
> If you do this, your prediction grid should overlap your observations, and
> the colors should reflect your color ramp. What you essentially did before
> was to make a prediction thousands of km away from your observations, and
> then all values will be the same.
>
> Best wishes,
> Jon
>
>
> On 8/4/2015 12:48 PM, Anand Sookun wrote:
>
>> Dear Jon and Roman
>>
>> Thanks for the reply.
>>
>> Im attaching the code.
>>
>> You may be right that the variogram may be problematic but it fitted
>> well visually.
>>
>> I think also that the prediction grid was not well created. I wiould be
>> grateful to have to hints.code how to create a useful grid and also for
>> the spplot or other alternatives
>>
>> I can send more info if required.
>>
>> Cheers
>>
>> Anand
>>
>> On Tue, Aug 4, 2015 at 1:39 PM, Jon Skoien <jon.skoien at jrc.ec.europa.eu
>> <mailto:jon.skoien at jrc.ec.europa.eu>> wrote:
>>
>>     Hi,
>>
>>     You have attached some data, but we still dont know exactly what you
>>     do with the data (do you use the logarithm, how many bins, did you
>>     project the data set...?). However, having had a quick look using
>>     the LatLong coordinates (not really recommended), I can see that the
>>     variogram from this data set is not particularly well defined, and
>>     it could well be that you fitted a model with pure nugget effect. In
>>     that case you will get the same prediction everywhere and no color
>>     differences.
>>
>>     Have a look at
>>      > summary(map)
>>     and particularly the summary of var1.pred.
>>     You could also plot the variogram of the data together with your
>>     model, vmf, and see how they fit.
>>
>>     I am not sure what you mean by not being able to create a prediction
>>     grid with data included. Do you mean that you want a grid which
>>     exactly overlays some of the data points? Matching one point should
>>     not be difficult, 2 and 3 should be possible, but you might get some
>>     problems with precision (FAQ 7.31).
>>
>>     Best wishes,
>>     Jon
>>
>>
>>
>>
>>     On 8/3/2015 5:30 PM, Anand Sookun wrote:
>>
>>>     Hi
>>>
>>>     Thank you Roman for your kind response.
>>>
>>>     The data is as attached which is part of the whole dataset.
>>>
>>>     My other problem is that im not able to create an appropriate
>>>     prediction grid with some data included.
>>>
>>>     The codes which failed to show colour ramps are
>>>
>>>     map <- krige(logcarbseq ~ 1, locations = carbon_seq, newdata =
>>>     map,model = vmf)
>>>     str(map)
>>>     print(spplot(map, "var1.pred", asp=1,
>>>     col.regions=bpy.colors(64),main="OK prediction, carbon"))
>>>     print(spplot(map, "var1.var",col.regions=cm.colors(64),asp=1,
>>>     main="OK prediction variance, carbon"))
>>>
>>>     I look forward to hopefully get some solutions.
>>>
>>>     Thanks again and warm regards
>>>
>>>     Anand
>>>
>>>     On Mon, Aug 3, 2015 at 4:09 PM, Roman Luštrik
>>>     <roman.lustrik at gmail.com <mailto:roman.lustrik at gmail.com>> wrote:
>>>
>>>         What is the variability of the plotted variable?
>>>
>>>         Cheers,
>>>         Roman
>>>
>>>         On Sun, Aug 2, 2015 at 11:03 AM, Anand Sookun
>>>         <<mailto:asookun at gmail.com>asookun at gmail.com
>>>         <mailto:asookun at gmail.com>> wrote:
>>>
>>>             Hi
>>>
>>>             I have kriged my data but the map shows uniform colours -
>>>             no gradual
>>>             contour colour plot on map
>>>
>>>             code: print(spplot(k40, "var1.pred", asp=1,
>>>             col.regions=bpy.colors(64),main="OK prediction, log-ppm Zn"))
>>>
>>>             thnaks for any help
>>>
>>>             Anand Sookun
>>>             --
>>>             -------------------------------------------------------
>>>             *Anand Sookun (**MPhil. **PhD Candidate, University of
>>>             Mauritius)*
>>>             *Director cum Freelance Consultant*
>>>             *Soft Sustainable Services (Mauritius)*
>>>             *Research and Consultancy*
>>>
>>>             Website: http://sustain-ability.webs.com/
>>>
>>>
>>>
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>>>
>>>     --
>>>     -------------------------------------------------------
>>>     /*Anand Sookun (*//*MPhil. *//*PhD Candidate, University of
>>>     Mauritius)*/
>>>     /*Director cum Freelance Consultant*/
>>>     /*Soft Sustainable Services (Mauritius)*/
>>>     /*Research and Consultancy*/
>>>
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>>>     <http://sustain-ability.webs.com/>http://sustain-ability.webs.com/
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>>
>>     --
>>     Jon Olav Skøien
>>     Joint Research Centre - European Commission
>>     Institute for Environment and Sustainability (IES)
>>     Climate Risk Management Unit
>>
>>     Via Fermi 2749, TP 100-01,  I-21027 Ispra (VA), ITALY
>>
>>     jon.skoien at jrc.ec.europa.eu <mailto:jon.skoien at jrc.ec.europa.eu>
>>     Tel:+39 0332 789205 <tel:%2B39%200332%20789205>
>>
>>     Disclaimer: Views expressed in this email are those of the individual
>> and do not necessarily represent official views of the European Commission.
>>
>>
>>
>>
>> --
>> -------------------------------------------------------
>> /*Anand Sookun (*//*MPhil. *//*PhD Candidate, University of Mauritius)*/
>> /*Director cum Freelance Consultant*/
>> /*Soft Sustainable Services (Mauritius)*/
>> /*Research and Consultancy*/
>>
>> Website: http://sustain-ability.webs.com/
>>
>>
>>
>> https://www.linkedin.com/profile/view?id=161468467&trk=nav_responsive_tab_profile_pic
>>
>>
> --
> Jon Olav Skøien
> Joint Research Centre - European Commission
> Institute for Environment and Sustainability (IES)
> Climate Risk Management Unit
>
> Via Fermi 2749, TP 100-01,  I-21027 Ispra (VA), ITALY
>
> jon.skoien at jrc.ec.europa.eu
> Tel:  +39 0332 789205
>
> Disclaimer: Views expressed in this email are those of the individual and
> do not necessarily represent official views of the European Commission.
>



-- 
-------------------------------------------------------
*Anand Sookun (**MPhil. **PhD Candidate, University of Mauritius)*
*Director cum Freelance Consultant*
*Soft Sustainable Services (Mauritius)*
*Research and Consultancy*

Website: http://sustain-ability.webs.com/


https://www.linkedin.com/profile/view?id=161468467&trk=nav_responsive_tab_profile_pic

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