[R-sig-Geo] Overlapping a grid shapefile with a NUTS3 shapefile to determine one average value for each NUTS3 region

[Janka Vanschoenwinkel]

Thank you very much Linus!

This would solve my problem of having point coordinates and the grid cells
would be filled.

However, with the raster package, can I read in an empty grid shapefile and
then add the values per grid through a text file? Because that was my first
problem: adding values from a text file to a grid based on longitude and
latitude centroids of each grid.

Thanks in advance!

Janka

2015-07-22 11:48 GMT+02:00 Linus Holtermann <holtermann at hwwi.org>:

> Sorry,
>
> the right command is "exctract", of course.
>
> Mit freundlichen Grüßen
>
>
> Linus Holtermann
> Hamburgisches WeltWirtschaftsInstitut gemeinnützige GmbH (HWWI)
> Heimhuder Straße 71
> 20148 Hamburg
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> Fax+49-(0)40-340576-776
> Internet: www.hwwi.org
> Email: holtermann at hwwi.org
>
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>
> -----Ursprüngliche Nachricht-----
> Von: R-sig-Geo [mailto:r-sig-geo-bounces at r-project.org] Im Auftrag von
> Linus Holtermann
> Gesendet: Mittwoch, 22. Juli 2015 11:46
> An: Janka Vanschoenwinkel; r-sig-geo at r-project.org
> Betreff: Re: [R-sig-Geo] Overlapping a grid shapefile with a NUTS3
> shapefile to determine one average value for each NUTS3 region
>
> Hello,
>
> take a look at the "overlay" command in the raster-package. Weight=TRUE
> may be a step in the right direction for your problem.
>
> Bests,
>
>
>
> Linus Holtermann
> Hamburgisches WeltWirtschaftsInstitut gemeinnützige GmbH (HWWI) Heimhuder
> Straße 71
> 20148 Hamburg
> Tel +49-(0)40-340576-336
> Fax+49-(0)40-340576-776
> Internet: www.hwwi.org
> Email: holtermann at hwwi.org
>
> Amtsgericht Hamburg HRB 94303
> Geschäftsführer: PD Dr. Christian Growitsch | Prof. Dr. Henning Vöpel
> Prokura: Dipl. Kauffrau Alexis Malchin
> Umsatzsteuer-ID: DE 241849425
>
>
> -----Ursprüngliche Nachricht-----
> Von: R-sig-Geo [mailto:r-sig-geo-bounces at r-project.org] Im Auftrag von
> Janka Vanschoenwinkel
> Gesendet: Mittwoch, 22. Juli 2015 11:37
> An: r-sig-geo at r-project.org
> Betreff: [R-sig-Geo] Overlapping a grid shapefile with a NUTS3 shapefile
> to determine one average value for each NUTS3 region
>
> Dear listmembers!
>
>
> I would like to add the average value of, let’s say soil moisture, to each
> NUTS3 region. However, soil moisture values are stored in little grids.
> Therefore, I need to find a way to calculate which grids overlap with a
> certain NUTS3 region in order to determine the average soil moisture value
> for that NUTS3 region. Visually, it can be compared to this picture where
> little grids approximate together the shape of US states:
> http://fieldguide.mt.gov/RangeMaps%5CESMapQUAD_9217.jpg
>
>
> It is possible that one NUTS3 region consists of 2 full grids and 3 half
> grids, while another NUTS3 region consists of only a 0.75 grid. It is also
> possible that some grids are empty because I don’t have values there.
>
>
> I assume that this requires 3 steps (but I am actually not sure):
>
>
>    - Step 1 would be to add the values of the text file to the grid
>    shapefile
>    - Step 2 would be to overlap the grid shapefile with the empty nuts3
>    shapefile
>    - Step 3 would be to write a new nuts3 shapefile which contains the
>    overlapped values
>
> My data and shapefiles can be found through the following link:
>
>
> https://drive.google.com/folderview?id=0By9u5m3kxn9yfjZtdFZLcW82SWpzT1VwZXE1a3FtRGtSdEl1c1NvY205TGpack9xSFc2T2s&usp=sharing
>
>
>    - mydata = read.csv("MyData.csv", header = TRUE) #contains coordinates
>    in latitude and longitude form that represent the centroids of each
>    “grid”.  #mydata also contains 1 variable (random numbers in this case)
>    that I want to match to the nuts3 regions in the “nuts” shapefile
>    - library(rgdal)
>    - grid <- readOGR(".", layer = "grid_025dd") #each grid contains de
>    centroid coordinates that should be linked to mydata in order to fill
> all
>    the grids with the variable of mydata
>    - nuts <- readOGR(".", layer = "NUTS_RG_60M_2006")
>
> Currently, I am nowhere. Maybe I don’t use the right keywords to google,
> but mostly, I am not used to working with coordinates. In the previous maps
> that I made, I was always capable of using some sort of objectid common to
> the data and the shapefile. Now, this is not the case. There should be an
> easy way to tell R to use the coordinates of mydata and combine them with
> the coordinates of the grids, but I can’t figure it out.
>
>
> Another issue that I face is that the values of the grids in ‘mydata’
> should fill up an entire grid. Yet, R recognizes the values as point
> values.
>
>
>
> Could someone please help me and point me in the correct direction for step
> 1 and 2? I think I should be able to do step 3 on my own.
>
> Thanks a lot for your help! I appreciate it a lot!
>
>
>
> Dear kindness,
>
>
> Janka
>
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-- 

[image: Logo UHasselt]Mevrouw Janka Vanschoenwinkel
*Doctoraatsbursaal - PhD *
Milieueconomie - Environmental economics

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