[R-sig-Geo] Environmental Risk Surface

Alex Mandel tech_dev at wildintellect.com
Thu Mar 20 17:35:39 CET 2014

All such tools are algorithms applied in some way via a raster
calculator. So the question is what formula or model of Risk Assessment
do you want to use. It can be a simple calculation based on your layers
and your knowledge of how important they are.

Or you can use many statistical formulas if you wanted. Marxan is just
one particular method of doing such calculations. There is no 1 way to
calculate risk. See http://cran.r-project.org/web/views/Environmetrics.html

Once you have the statistical model you want to apply, you can use
predict to generate values over your area based on your other layers.

The question is not if R can do it, but what do you want R to do.


On 03/20/2014 09:00 AM, Manuel Spínola wrote:
> Thank you very much Mike.
> I have the rasters made with the package ratser, using the function
> rasterize, distance and distance from points.  I know how to model when you
> have presence or presence/absence data, but in this situation I don´t have
> those type of data and I am looking for a way to do a risk assessment in R.
>  I was reading, an apparently Environmental Risk Surface is something that
> could be done with that type of information.  A software like Marxan seems
> to do that type of analysis, but I don´t know the capabilities of R to do
> such type of analysis.
> Best,
> Manuel
> 2014-03-20 9:07 GMT-06:00 Michael Treglia <mtreglia at gmail.com>:
>> Manuel,
>> Please correct me if I misunderstand, but you've got vector layers of
>> Roads, Wetlands, and specific locations, and are need to make Raster layers
>> of how far each pixel would be from these types features, and then combine
>> these distance rasters through some sort of computation to map risk. Right?
>> I don't think there is package that would do this all for you
>> automatically (and there are a lot of decisions you'll probably have to
>> make), but I think the Raster package should have all of the necessary
>> tools - in particular the functions rasterize(), distance() , and the
>> raster algebra functions [though to initially import shapefiles you'll have
>> to use another package, maybe rGDAL]. The documentation for the Raster
>> package is here: http://cran.r-project.org/web/packages/raster/index.html
>> Post-back as you have specific questions on how to execute specific steps,
>> (and look at examples for specific steps in the documentation - the raster
>> package is very well documented).
>> Cheers,
>> Mike
>> On Wed, Mar 19, 2014 at 9:05 PM, Manuel Spínola <mspinola10 at gmail.com>wrote:
>>> Thank you Mike,
>>> I am thinking in overlay several raster layers, mainly distance raster
>>> (distance to roads, to specific locations, to wetlands, etc) to assess the
>>> risk of a disease spread that is not yet in the country but could enter
>>> through migratory birds.
>>> Best,
>>> Manuel
>>> 2014-03-19 19:08 GMT-06:00 Michael Treglia <mtreglia at gmail.com>:
>>> Hi Manuel,
>>>> There may be multiple types of environmental risk surfaces, based on
>>>> different variables, and using different methods to effectively create
>>>> indices of risk. Can you provide some more detail about what you are trying
>>>> to do? If there is a paper that explains the general methodology, that
>>>> would be helpful? If not, perhaps an explanation of the general workflow
>>>> you are thinking, with the data types (raster/vector) would be helpful.
>>>> Also, are there specific steps for which you need help? (e.g.,
>>>> data-processing, multi-layer raster calculations, etc?)
>>>> Cheers,
>>>> Mike
>>>> 2014-03-19 17:37 GMT-05:00 Manuel Spínola <mspinola10 at gmail.com>:
>>>>> Dear list members,
>>>>> Is there any way to do an Environmental Risk Surface in R?
>>>>> Best,
>>>>> Manuel
>>>>> --
>>>>> *Manuel Spínola, Ph.D.*
>>>>> Instituto Internacional en Conservación y Manejo de Vida Silvestre
>>>>> Universidad Nacional
>>>>> Apartado 1350-3000
>>>>> Heredia
>>>>> mspinola at una.ac.cr
>>>>> mspinola10 at gmail.com
>>>>> Teléfono: (506) 2277-3598
>>>>> Fax: (506) 2237-7036
>>>>> Personal website: Lobito de río <
>>>>> https://sites.google.com/site/lobitoderio/>
>>>>> Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/>
>>>>>         [[alternative HTML version deleted]]
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