[R-sig-Geo] 答复: How to adjust two maps with different extent in R

[Zhang Tianyi]

Thank you!! This works!


________________________________
·¢¼þÈË: R-sig-Geo <r-sig-geo-bounces at r-project.org> ´ú±í Francisco Rodriguez Sanchez <f.rodriguez.sanc at gmail.com>
·¢ËÍʱ¼ä: 2016Äê12ÔÂ19ÈÕ 19:28
ÊÕ¼þÈË: r-sig-geo at r-project.org
Ö÷Ìâ: Re: [R-sig-Geo] How to adjust two maps with different extent in R

Hi Tianyi,

I think raster::rotate will do what you need

https://www.rdocumentation.org/packages/raster/versions/2.5-8/topics/rotate
rotate | RDocumentation<https://www.rdocumentation.org/packages/raster/versions/2.5-8/topics/rotate>
www.rdocumentation.org
Rotate a Raster* object that has x coordinates (longitude) from 0 to 360, to standard coordinates between -180 and 180 degrees. Longitude between 0 and 360 is frequently used in global climate models.




Cheers,

Paco


El 19/12/2016 a las 07:50, Zhang Tianyi escribi¨®:
> Two maps with different extents
>
> I am using R to process two maps (raster package). I have two maps with both WGS84 coordinates see figure. [image of map] <https://i.stack.imgur.com/bD84y.png>
>
> But one layer is from -180 to 180 in longitude (the map on surface) another one is from 0 to 360 (the map on the bottom).
>
> I need to adjust the bottom layer to -180 to 180 so that they can match. How can I do that?
>
> I think I need to find all grid greater than 180 and then minus 360. But I cannot find the longitude vector and cannot modify it from the Raster data.
>
> Description of the map is:
>
> class       : RasterLayer
> dimensions  : 94, 192, 18048  (nrow, ncol, ncell)
> resolution  : 1.865234, 1.883872  (x, y)
> extent      : 0, 358.125, -88.542, 88.542  (xmin, xmax, ymin, ymax)
> coord. ref. : +proj=longlat +datum=WGS84 +ellps=WGS84 +towgs84=0,0,0
> data source : in memory
> names       : TMAX_2015_01_01
> values      : 220.9, 324.3  (min, max)
>
>
> Regadrs,
> Tianyi Zhang
>
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>
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--
Dr Francisco Rodriguez-Sanchez
Integrative Ecology Group
Estacion Biologica de Do?ana - CSIC
Avda. Americo Vespucio s/n
41092 Sevilla (Spain)
http://bit.ly/frod_san

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[https://i.stack.imgur.com/bD84y.png]

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