[R-sig-Geo] Mapping Pacific centered map for Spatial analysis

sownal chand @own@|ch@nd|m@ @end|ng |rom gm@||@com
Sun Mar 13 17:31:07 CET 2022


Hello sir(s),

Firstly I would like to thank both of you for your input in assistance me
with my problems that I am facing using R aa a spatial analysis tool.

I have been trying to do this for past 6 months and have found it really
challenging but quite interesting as well.

I will look at the codes and try to complete my project.

Sir all credits goes to both of you since you have provided timely response
to my questions.

If I do face any issues will try to consult again.

Yours sincerely
Sownal

On Mon, Mar 14, 2022, 02:07 Roger Bivand <Roger.Bivand using nhh.no> wrote:

> On Sun, 13 Mar 2022, Micha Silver wrote:
>
> >
> > On 13/03/2022 01:41, sownal chand wrote:
> >>  Hello Sir/Madam,
> >>
> >>  I am Sownal Chand, from Fiji Islands and am currently working on a
> project
> >>  which involves spatial analysis of climate data (Temperature, rainfall,
> >>  etc). I have been able to write codes in R for Point interpolations of
> >>  these parameters but I require some assistance in mapping these raster
> >>  files on the southwest pacific maps. For example, a map of Fiji
> Islands  (
> >>
> https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.pinterest.com%2Fpin%2F740982944911004875&data=04%7C01%7CRoger.Bivand%40nhh.no%7C3d492fafcd7247d2090e08da04cde59b%7C33a15b2f849941998d56f20b5aa91af2%7C0%7C0%7C637827580063300234%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=5xNJDee6Glb%2FW7MCkO8biDzHl1%2Bv5hc%2FBsU%2FmO9neLE%3D&reserved=0
> >>  ) and I am facing some
> >>  difficulties in making these plots.
> >>
> >>  I hope that some expert would be willing to help me with this and the
> >>  map's
> >>  CRS setting is a bit confusing and I am a beginner in this area ( i. e,
> >>  spatial analysis using R). I have been looking at tutorials and codes
> to
> >
> >
> > There are tons of online resources. You could, for example, refer to:
> >
> >
> https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgeocompr.robinlovelace.net%2F&data=04%7C01%7CRoger.Bivand%40nhh.no%7C3d492fafcd7247d2090e08da04cde59b%7C33a15b2f849941998d56f20b5aa91af2%7C0%7C0%7C637827580063300234%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=08BU9QbKjLNh5TkKeu38etqzU%2FOysx7fqsGoVq3kImw%3D&reserved=0
> >
> >
> >>  crop country boundaries and shapefiles and still found lots of errors
> in
> >>  my
> >>  codes.
> >
> >
> > You have raised a few different questions. Would you mind to post what
> you
> > have done so far, and point out the errors and difficulties?
> >
>
> It does also seem possible that the problems are initially caused by using
> geographical (spherical) coordinates rather than projected coordinates.
> Projection of the input points to say EPSG:3460, or for the broader
> Pacific Basin EPSG:3832, may be helpful. See
> https://www.asprs.org/wp-content/uploads/2012/05/10-2000-fiji.pdf for the
> then (publication 2000) valid description of why EPSG only seems to record
> Fiji with 1956 (international ellipsoid) and 1986 (WGS1972 ellipsoid).
>
> EPSG:4326 can be transformed to EPSG:3460 with 2m accuracy. Using then a
> projected planar extent in the local grid, the problem of crossing 180
> degrees is removed. In addition, the interpolation will use metres not
> degrees as the metric of the positions of the points and grid cells. The
> planar representation should also remove plotting problems.
>
> Hope this helps,
>
> Roger
>
> >
> >>  Hoping to find solutions to my problems and learn from this.
> >>
> >>  yours sincerely
> >>  sownalc
> >>  Contact: sownalchand using gmail.com
> >>  PH +679 2960779
> >>
> >>   [[alternative HTML version deleted]]
> >>
> >>  _______________________________________________
> >>  R-sig-Geo mailing list
> >>  R-sig-Geo using r-project.org
> >>
> https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstat.ethz.ch%2Fmailman%2Flistinfo%2Fr-sig-geo&data=04%7C01%7CRoger.Bivand%40nhh.no%7C3d492fafcd7247d2090e08da04cde59b%7C33a15b2f849941998d56f20b5aa91af2%7C0%7C0%7C637827580063300234%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=BbbD%2BNIDVs82yx2JHiO3PTxUD%2BBUH%2FXdpirZCFGAmn0%3D&reserved=0
> >
> >
>
> --
> Roger Bivand
> Emeritus Professor
> Department of Economics, Norwegian School of Economics,
> Postboks 3490 Ytre Sandviken, 5045 Bergen, Norway.
> e-mail: Roger.Bivand using nhh.no
> https://orcid.org/0000-0003-2392-6140
> https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en
>

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