[R-sig-Geo] Environmental Risk Surface

[Alex Mandel]

http://cran.r-project.org/web/packages/raster/vignettes/Raster.pdf

See the part about Raster Algebra.

Enjoy,
Alex

On 03/20/2014 10:49 AM, Manuel Spínola wrote:
> Thank you very much Alex.
> 
> I want to do simple calculations.
> 
> Best,
> 
> Manuel
> 
> 
> 2014-03-20 10:35 GMT-06:00 Alex Mandel <tech_dev at wildintellect.com>:
> 
>> 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.
>>
>> Thanks,
>> Alex
>>
>>
>> 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
>>>>>>> COSTA RICA
>>>>>>> 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]]
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> R-sig-Geo mailing list
>>>>>>> R-sig-Geo at r-project.org
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>>
>>
>>
> 
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