[R-sig-eco] do the standard R analysis functions handle spatial "grid" data?

[Robert J. Hijmans]

You can also do this with the 'raster' package. See  ?raster::predict
Robert


On Mon, Jul 12, 2010 at 11:40 PM, Kingsford Jones
<kingsfordjones at gmail.com> wrote:
> Not sure which 'logistic function' you're asking about, but logistic
> regression is a case of the generalized linear model and can be fit
> with base::glm.  It's been awhile since I've done this sort of thing
> but as I recall I exported stacked rasters of predictors as XYZ ASCII
> files (possibly after multiplying floating points by powers of 10 and
> rounding to work with integers), and then merged on unique xy values
> to form a matrix with one location (e.g raster cell centroid) per row
> and k+2 columns where k is the number of layers and +2 for the x and y
> values. Note that any glm inferences (including predictive inference)
> will assume independent errors conditional on the model matrix.  To
> use the xy values for independence diagnostics etc you'll want a
> projection that preserves distance.
>
> The rgdal, maptools and sp packages provide functions and classes for
> working w/ spatial data (see the spatial Task View on CRAN).  Also, it
> sounds as though the adehabitat package will be useful for your
> application, and possibly the grasp and ModelMap packages as well.
>
> Kingsford Jones
>
>
>
> On Mon, Jul 12, 2010 at 8:51 PM, Chris Howden
> <chris at trickysolutions.com.au> wrote:
>> Hi everyone,
>>
>> I'm doing a resource function analysis with radio collared dingos and GIS
>> info.
>>
>> The ecologist I'm working with wants to send me the data in a 'grid
>> format'...straight out of ARCVIEW GIS.
>>
>> I want to model the data using a GLM and maybe a LOGISTIC model as well.
>> And
>> I was planning on using the glm and logistic functions in R.
>>
>>
>> Now I'm pretty sure that these functions require the data to be in a 2-D
>> spreadsheet format. And for me to call the responses and predictors as
>> columns from a data.frame (or 2-D matrix)
>>
>> However I'm being told they can handle the data in a 'grid' format. So I'm
>> pretty sure this would mean I would be calling the responses and
>> predictors
>> as 2-d matrices...and I don't think these functions can do that?
>>
>>
>> Can anyone enlighten me?
>>
>> Am I right in thinking these function cannot handle data in a 3-D 'grid'
>> format and require data to be entered as a 2-d data.frame or matrix?
>>
>>
>> Are there other special functions out there that can handle this type of
>> data, and I should be using these instead?
>>
>> Thanks for your help
>>
>> Chris Howden
>> Founding Partner
>> Tricky Solutions
>> Tricky Solutions 4 Tricky Problems
>> Evidence Based Strategic Development, IP development, Data Analysis,
>> Modelling, and Training
>> (mobile) 0410 689 945
>> (fax / office) (+618) 8952 7878
>> chris at trickysolutions.com.au
>>
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>
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