interpolation to new points between geo coordinates

classic Classic list List threaded Threaded
2 messages Options
Reply | Threaded
Open this post in threaded view
|

interpolation to new points between geo coordinates

Jan Näs-2
Hi

I have a data set with geo coordinates and values for each coordinate.
I want to interpolate the values to new positions on a finer grid,
also geo coordinates.
I have looked at the fields package (interp.surface) and the akima
package (interp) but cant quite figure what I am doing wrong, or if
these functions suits my needs.

I have the two data set:

grid_1:

  lat  lon  value
1 56.5  11.1  53
2 56.6 11.1 53.1
3 56.7 11.12 52.1
4 56.5 11.2 52.9
...etc.

and a new grid

grid_2
  lat  lon
1 55.52 11.11
2 55.53 11.115
3 55.54 11.12
...etc.


And I want interpolated values for grid_2.
Any ideas?
/Jan

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Reply | Threaded
Open this post in threaded view
|

Re: interpolation to new points between geo coordinates

Jon Skoien
Jan,

There are a lot of packages that can help you, the best one depends on
your needs (with or without prediction uncertainty, format of results,
different options) and the size of your problem.
CRAN has a spatial Task View
http://cran.r-project.org/web/views/Spatial.html
with a short description of most packages dealing with spatial data. I
think the functions you mentioned should be able to solve your problems,
but I dont have experience with either of them. It is impossible to know
what you are doing wrong as you did not post any error messages.
For increasing the resolution of your data, you can also try
disaggregate or resample in the raster package. gstat, with  automap or
intamap as simpler interfaces can also be used for geostatistical
interpolation to the higher resolution grid, also giving you a
prediction uncertainty. You should in general be careful with
interpolation of lat-lon data, consider using spTransform to get
projected coordinates if you use any of the geostatistical methods.

You will for spatial questions generally get quicker response from the
r-sig-geo mailinglist.

Best wishes,
Jon


On 02-Jul-12 10:47, Jan Näs wrote:

> Hi
>
> I have a data set with geo coordinates and values for each coordinate.
> I want to interpolate the values to new positions on a finer grid,
> also geo coordinates.
> I have looked at the fields package (interp.surface) and the akima
> package (interp) but cant quite figure what I am doing wrong, or if
> these functions suits my needs.
>
> I have the two data set:
>
> grid_1:
>
>    lat  lon  value
> 1 56.5  11.1  53
> 2 56.6 11.1 53.1
> 3 56.7 11.12 52.1
> 4 56.5 11.2 52.9
> ...etc.
>
> and a new grid
>
> grid_2
>    lat  lon
> 1 55.52 11.11
> 2 55.53 11.115
> 3 55.54 11.12
> ...etc.
>
>
> And I want interpolated values for grid_2.
> Any ideas?
> /Jan
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.


--
Jon Olav Skøien
Joint Research Centre - European Commission
Institute for Environment and Sustainability (IES)
Land Resource Management Unit

Via Fermi 2749, TP 440,  I-21027 Ispra (VA), ITALY

[hidden email]
Tel:  +39 0332 789206

Disclaimer: Views expressed in this email are those of the individual and do not necessarily represent official views of the European Commission.

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.