[R-sig-Geo] Elevation data

[Miluji Sb]

Thank you for your reply. This is what I did:

###
library(data.table)
library(raster)
library(rgdal)
library(foreign)

elevation_world <- getData('worldclim', var='alt', res=2.5)

# Aggregate Elevation to 1 degree
elevation_world_1deg <- aggregate(elevation_world, fact = 24, fun = sum)

# Extract by lon lat (1° x 1° - gcp_grid)
elevation <- cbind(gcp_grid, alt = extract(elevation_world_1deg, gcp_grid))

elevation <- as.data.frame(elevation)
###

Is this correct? Thanks again!

Sincerely,

Milu

On Fri, Jan 13, 2017 at 3:11 AM, Bacou, Melanie <mel at mbacou.com> wrote:

> R raster::getData("SRTM", ...) will return elevation rasters at 90m
> resolution.
> See:
> https://www.rdocumentation.org/packages/raster/versions/2.5-
> 8/topics/getData
> http://www.cgiar-csi.org/data/srtm-90m-digital-elevation-database-v4-1
>
> --Mel.
>
>
> On 1/11/2017 6:26 AM, Miluji Sb wrote:
>
>> Dear Michael,
>>
>> Thank you for your reply and the suggestions.
>>
>> Ideally, I would like a raster from which I can extract elevation at 1° x
>> 1° resolution. I do not have much experience with working with DEM but
>> have
>> work with data such as GPW.
>>
>> I will definitely look at the datasets. Could you kindly suggest one that
>> I
>> could convert to raster and extract? Hope that's not a silly question.
>>
>> Sincerely,
>>
>> Milu
>>
>> On Wed, Jan 11, 2017 at 1:51 AM, Michael Sumner <mdsumner at gmail.com>
>> wrote:
>>
>> Passed through? Maybe you want ?raster::extract
>>>
>>> There are a few versions of global elevation on CRAN, necessarily at low
>>> resolution but no overall summary afaik (someone should do this :).
>>>
>>> This is one: https://cloud.r-project.org/web/packages/GEOmap/index.html
>>>
>>> If you have the stomach for development versions of packages see elevatr:
>>> https://github.com/jhollist/elevatr
>>>
>>> I tend to have the high-resolution files at hand because we use them
>>> constantly, the main ones are Gebco14/Gebco08 and Etopo1/Etopo2 (from
>>> Smith-Sandwell).
>>>
>>> There's a reasonable overview here, you probably should find a specific
>>> data set that is at the resolution you are after already, and you can
>>> cite
>>> its derivation for your work:
>>>
>>> http://vterrain.org/Elevation/global.html
>>>
>>> Cheers, Mike.
>>>
>>> On Wed, 11 Jan 2017 at 10:20 Miluji Sb <milujisb at gmail.com> wrote:
>>>
>>> Dear all.
>>>>
>>>> Is there a way to download global elevation data at the 1° x 1°
>>>> resolution
>>>> in R using a given set of coordinates?
>>>>
>>>> I know about the getData() function but can many coordinates be passed
>>>> through this? Thanks!
>>>>
>>>> Sincerely,
>>>>
>>>> Milu
>>>>
>>>>          [[alternative HTML version deleted]]
>>>>
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>>>
>>>
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