[R-sig-Geo] reboxing with package=GSIF

[Tomislav Hengl]

On 05/11/2012 05:58, Tom Roche wrote:
>
> summary: how to use GSIF::make.3Dgrid for general-purpose "reboxing," or
> 3D interpolation? Particularly, can one use varying vertical bounds
> rather than the same "standard depths" for both input and output?
>

Yes. You can predict at irregular locations by using 
SpatialPointsDataFrame object e.g.:

 > obj = data.frame(x = 100, y = 100, d = -.2, DEM = 122)
 > coordinates(obj) <- ~x+y+d

The names of coordinate fields in the gstatModel and for the new 
locations must correspond. See also:

http://gsif.r-forge.r-project.org/tutorial_eberg.php#visualizing_uncertainty

> details:
>
> Apologies if the following questions reveal a profound ignorance of
> spatiality or geostatistics (which I'm learning slowly and "on-the-fly")
> and if I'm missing something simple regarding GSIF; unfortunately the
> tutorial
>
> http://gsif.r-forge.r-project.org/tutorial_eberg.php
>

Yes. I'm also on the edge here :)

> seems to require more geostatistical background than I currently have.
>
> https://stat.ethz.ch/pipermail/r-sig-geo/2012-November/016573.html
>>>> [I seek to] incorporate N2O emissions inventories (EIs), initial
>>>> conditions (ICs), and boundary conditions (BCs) from relatively
>>>> coarse-scaled global inventories (with horizontal grids on the order
>>>> of degrees lon-lat) into a [finer-scaled] regional atmospheric model
>>>> (12-km LCC horizontal). The [EIs] are [surface/2D] and I now know
>>>> how to "regrid," or interpolate from one 2D grid to another.
>
>>>> However the model and [its] IC/BCs are 3D[, and] have [both]
>>>> different vertical layering (i.e., [number and height of layers])
>>>> [and] different horizontal grids. I'd like to know: is there R code
>>>> available that will "rebox," i.e., interpolate vertically as well as
>>>> horizontally?
>
> To further specify: my global IC/BC estimates mass concentration for
> each box/voxel in a regular, unprojected grid 1.875° x 2.5° x 56 levels.
> I want to "rebox" from global IC/BCs to model-ready IC/BCs, where the
> latter must estimate mass concentration over a regular grid that
> horizontally projects to LCC over North America at 12-km resolution, and
> which has 34 vertical levels. (Both the vertical and horizontal extents
> of the model-ready IC/BC are subsets of the global extents.) I can
> compute the sizes of the boxes, so I can compute the mass in each input
> box, and recompute the output concentrations, presuming I can learn how
> to rebox the masses.
>
> https://stat.ethz.ch/pipermail/r-sig-geo/2012-November/016578.HTML
>> I've produced some 3D interpolation examples in the experimental
>> package GSIF (under construction). You can actually create some kind
>> of voxels via the SpatialPixelsDataFrame class
>
>> http://gsif.r-forge.r-project.org/make.3Dgrid-method.html
>
>> and then predict at those locations.
>
> From
>
> http://gsif.r-forge.r-project.org/make.3Dgrid-method.html
>
> it appears one can provide as input
>
> * an unprojected SpatialPixelsDataFrame or RasterBrick
>
> * a PROJ.4 string defining the output CRS
>
> * a "list of standard depths"
>
> and get an output list of SpatialPixelsDataFrame's (one per standard
> depth). From the description, it seems like GSIF::make.3Dgrid is doing a
> 2D regridding at each standard depth, such that the heights of the input
> box/voxels must match that of the output box/voxels. Is that correct?
>
> If not, how can one rebox from an input with one set of layer heights
> (or vertical bounds) to an output with another set of layer heights?
> Can `gdalwarp` do that, or is it (like, IIUC, raster::projectRaster)
> restricted to 2D?
>
> Your assistance is appreciated! Tom Roche <Tom_Roche at pobox.com>
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>