[R-sig-Geo] CRS for the European Biogeographical Regions in R

[Albin Blaschka]

Hello!

> Is a .qpj file a projection written by QGIS for some reason?

http://hub.qgis.org/issues/2123
http://hub.qgis.org/issues/2154

Found here:
https://github.com/mapbox/node-srs/issues/34
> It's [.qpj] what GDAL's OSRExportToWkt() returns and what can fed into OSRImportFromWkt() without hassle.
 > While OGR morphs the WKT into an ESRI WKT format for the .prj and back


Greetings,
Albin


Am 09.02.2015 um 16:23 schrieb Barry Rowlingson:
> On Sun, Feb 8, 2015 at 12:54 PM, Roland Kaiser <kardinal.eros at gmail.com> wrote:
>> Hi!
>>
>> Sorry for the confusion, I followed the link on the top the page "Note: new version is available!“.
>> For some reason, this ZIP archive has a *.qpj instead of *.prj file.
>>
>> Of course, readOGR treats the *prj correctly, if present!
>
>
> With the qpj file:
>
>   > r = readOGR(".","BiogeoRegions2011")
> OGR data source with driver: ESRI Shapefile
> Source: ".", layer: "BiogeoRegions2011"
> with 12 features and 5 fields
> Feature type: wkbPolygon with 2 dimensions
>
> Fails:
>
>   > proj4string(r)
> [1] NA
>
> But if you simply rename the .qpj file as .prj then:
>
>   > file.rename("BiogeoRegions2011.qpj","BiogeoRegions2011.prj")
> [1] TRUE
>
> Maybe...
>
>   > r = readOGR(".","BiogeoRegions2011")
> OGR data source with driver: ESRI Shapefile
> Source: ".", layer: "BiogeoRegions2011"
> with 12 features and 5 fields
> Feature type: wkbPolygon with 2 dimensions
>
> It all works:
>
>   > proj4string(r)
> [1] "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000
> +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs"
>
> Is a .qpj file a projection written by QGIS for some reason?
>
> Barry
>
>> -Roli
>>
>>> Am 08.02.2015 um 12:37 schrieb Barry Rowlingson <b.rowlingson at lancaster.ac.uk>:
>>>
>>> On Sat, Feb 7, 2015 at 4:53 PM, Roland Kaiser <kardinal.eros at gmail.com> wrote:
>>>
>>>> #       the projection information is given in the *.qpj file
>>>
>>> I can't see a *.qpj file in that shapefile. There is a *.prj file
>>> which contains projection info.
>>>
>>>> #       unfortunately, it is not read from the dataset by the OGR driver
>>>
>>> The *.prj file **is** read when using readOGR:
>>>
>>>> r=readOGR(".","BiogeoRegions2011")
>>> OGR data source with driver: ESRI Shapefile
>>> Source: ".", layer: "BiogeoRegions2011"
>>> with 12 features and 4 fields
>>> Feature type: wkbPolygon with 2 dimensions
>>>> proj4string(r)
>>> [1] "+proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000
>>> +ellps=GRS80 +units=m +no_defs"
>>>
>>> - that's a full projection specification, rather than an epsg code
>>> though, because that's what's in the file.
>>>
>>>> #       we have do define it manually by specifing argument p4s
>>>
>>> No we don't!
>>>
>>>> pg <- readOGR(dsn = "BiogeoRegions2011_shapefile",
>>>>         layer = "BiogeoRegions2011", p4s = "+init=epsg:3035")
>>>
>>> Is the .prj file text coding the same projection as epsg:3035?
>>> http://epsg.io/ says 3035 is:
>>>
>>> +proj=laea +lat_0=52 +lon_0=10 +x_0=4321000 +y_0=3210000 +ellps=GRS80
>>> +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
>>>
>>> So yes. But there's no need to specify it in readOGR since you have
>>> the .prj file. The maptools functions readShapeSpatial and friends
>>> ignore the .prj file - I don't know why they exist any more!
>>>
>>>> r2=readShapeSpatial("BiogeoRegions2011.shp")
>>>> proj4string(r2)
>>> [1] NA
>>>
>>> Ouch.
>>>
>>> Barry
>>
>
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-- 
| Albin Blaschka, Mag.rer.nat.
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