[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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>>
>> --
>> 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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