Thanks heaps to all for your effort. If I go to another GEOSTAT ill bring more giant crab this time.
The creator of the .nc file also looked at this webpage: http://www.pkrc.net/wrf-lambert.html It seemed like the right proj4 string might be this one: +proj=lcc +lat_1=25.0 +lat_2=45.0 +lat_0=38.0 +lon_0=-100.0 +a=6370 +b=6370 +towgs84=0,0,0 +no_defs However this projection also does not allow me to adequately plot the locations on the raster. Here is the .nc file. it contains several layers. https://www.dropbox.com/s/yto3linsgom3zi7/results_us_future_output_none_0.nc?dl=0 2016-02-23 2:25 GMT-07:00 Michael Sumner <mdsum...@gmail.com>: > On Tue, 23 Feb 2016 at 20:09 Roger Bivand <roger.biv...@nhh.no> wrote: > > > On Tue, 23 Feb 2016, Alex Mandel wrote: > > > > > I made an attempt at it too. Investigating the original data, I'm not > > > sure that the projection information supplied is correct for the data > > > linked. When I load up the data in a unprojected space, the coordinates > > > don't look at all similar to any Lambert projected data I have, they > > > actually look like Lat/Lon in some unprojected coordinate system, > > > perhaps a different spheroid than expected. > > > > Does anyone have a link to the original data? Is is possible that this is > > the General Oblique Transformation used by modellers - that is something > > that feels like longlat but is recentred and oblique? Example at the very > > end of my GEOSTAT talk last year (slides 81-83): > > > > http://geostat-course.org/system/files/geostat_talk_150817.pdf > > > > Roger > > > > > For what it is worth, the General Oblique Transformation is not the only > example - it's very common for modellers to have a mesh that has the > "mostly-properties" of a projection, but is not actually describable with > standard transform + affine parameters. The main cases that I've seen are > polar stereographic, equal area or oblique Mercator. Often they really are > simple transforms and you can reconstruct without loss, but it's not > usually possible to tell without exploration. It's an interesting > dis-connect to see code that builds a mesh with certain properties, then > only stores longitudes and latitudes - when it could be done with standard > tools and be stored and used much more efficiently. > > (I've seen Lambert Conformal Conic and Lambert Azimuthal Equal Area > terminology conflated in this context too. ) > > I'm also interested to explore the original data. > > Cheers, Mike. > > > > > > > > > -Alex > > > > > > On 02/22/2016 10:17 PM, Frede Aakmann Tøgersen wrote: > > >> Hi > > >> > > >> I tried to make it work but I had to give up. I wanted to reproject > the > > Lamberth conformal conic coordinates to long-lat but it didn't work. > > >> > > >> Perhaps someone can see what I did wrong. Here is what I did (data in > R > > binary format and figure in png format both attached): > > >> > > >> library(raster) > > >> library(maptools) > > >> data(wrld_simpl) > > >> > > >> r <- raster("raster.grd") > > >> projection(r) > > >> ## > NA > > >> > > >> uro <- read.table("clean urosaurus records.csv", h = TRUE, sep = ",") > > >> coordinates(uro) <- ~lon+lat > > >> > > >> ## Set projections for the 3 data sets > > >> > > >> ## Lamberth's confocal conic projection with given parameters > > >> crs(r) <- "+proj=lcc +lat_0=38.0 +lon_0=-100 +lat_1=25.0 +lat_2=45.0 > > +ellps=WGS84" > > >> projection(r) > > >> > > >> ## Assume that lon, lat are geographical coordinates (degrees decimal) > > >> proj4string(uro) <- CRS("+proj=longlat +datum=WGS84") > > >> > > >> ## wrld_simpl is in geographical coordinates > > >> proj4string(wrld_simpl) > > >> > > >> ## Make figure in png format > > >> ## Of course plotting data with 2 different projections will give > > >> ## some distortions > > >> pdf("uro.png") > > >> > > >> plot(r) > > >> points(uro) > > >> plot(wrld_simpl, add = TRUE) # World will be clipped to extent of 'r' > > >> > > >> dev.off() > > >> > > >> extent(r) > > >> ## class : Extent > > >> ## xmin : -131.4368 > > >> ## xmax : -68.56323 > > >> ## ymin : 12.35567 > > >> ## ymax : 50.26619 > > >> > > >> ## Reproject the raster to long-lat > > >> ## This doesn't work (collapsed domain) > > >> rp <- projectRaster(r, crs = "+proj=longlat +datum=WGS84 +no_defs > > +ellps=WGS84 +towgs84=0,0,0") > > >> > > >> ## Because > > >>> extent(rp) > > >> ## class : Extent > > >> ## xmin : -100.0015 > > >> ## xmax : -99.68557 > > >> ## ymin : 37.70658 > > >> ## ymax : 38.00046 > > >> > > >> ## Save data in R binary format > > >> save(list = c("r", "uro", "wrld_simpl"), file = "uro.RData") > > >> > > >> > > >> Yours sincerely / Med venlig hilsen > > >> > > >> Frede Aakmann Tøgersen > > >> Specialist, M.Sc., Ph.D. > > >> Plant Performance & Modeling > > >> > > >> Technology & Service Solutions > > >> T +45 9730 5135 > > >> M +45 2547 6050 > > >> fr...@vestas.com > > >> http://www.vestas.com > > >> > > >> Company reg. name: Vestas Wind Systems A/S > > >> This e-mail is subject to our e-mail disclaimer statement. > > >> Please refer to www.vestas.com/legal/notice > > >> If you have received this e-mail in error please contact the sender. > > >> > > >> > > >> > > >> -----Original Message----- > > >> From: R-sig-Geo [mailto:r-sig-geo-boun...@r-project.org] On Behalf Of > > Agus Camacho > > >> Sent: 22. februar 2016 19:20 > > >> To: t...@wildintellect.com > > >> Cc: r-sig-geo > > >> Subject: Re: [R-sig-Geo] adapting spatial points and wrld_smpl to a > > reference system implicit in a .nc file > > >> > > >> Thanks Alex, but the locations still fall in the sea when i plot them > > using > > >> your recommended Solution. I looked at the sites you proposed and they > > have > > >> other values for lat_1, lat_0, etc.. > > >> > > >> 2016-02-22 11:04 GMT-07:00 Alex M <tech_...@wildintellect.com>: > > >> > > >>> On 02/22/2016 09:50 AM, Agus Camacho wrote: > > >>>> Dear all, > > >>>> > > >>>> Im trying to overlap these points: > > >>>> > > >>> > > > https://www.dropbox.com/s/awdclg4cvsdngej/clean%20urosaurus%20records.csv?dl=0 > > >>>> > > >>>> and a wrld_simpl object: > > >>>> library(maptools) > > >>>> data(wrld_simpl) > > >>>> > > >>>> Over this raster layer > > >>>> > > >>> > > > https://www.dropbox.com/sh/qcw174tgogpnz7s/AAByDc3TeyFe3W4nEqTFix6Oa?dl=0 > > >>>> > > >>>> This rastr comes from a .nc file without a reference system. The > > author > > >>> of > > >>>> that .nc file gave me the following data about the .nc. > > >>>> > > >>>> The projection is *Lambert conformal conic* projection > > >>>> CEN_LAT = 38.0 > > >>>> CEN_LON = -100.0 > > >>>> TRUELAT1 = 25. > > >>>> TRUELAT2 = 45. > > >>>> > > >>>> However, despite i have gone through many sites in the internet, i > > cant > > >>>> figure it out: > > >>>> > > >>>> a) if that is all the data i need to set a reference system for my > > points > > >>>> and the wrld_simp object. > > >>>> > > >>>> b) how to change a typical CRS object with such data > > >>>> > > >>>> Ex.CRS ("+proj=lcc+lat_0=38.0+lon0_2=-100+ellps=WGS84") > > >>>> > > >>>> Where do i enter the TRUELAT and CENLAT values? > > >>>> Are there any site that explains easily what the fields in the CRS > > mean > > >>> and > > >>>> how to change them? > > >>>> > > >>>> Thanks in advance. > > >>>> > > >>> > > >>> https://github.com/OSGeo/proj.4/wiki/GenParms > > >>> https://trac.osgeo.org/proj/wiki/GenParms > > >>> > > >>> I believe: > > >>> +lat_0 = CEN_LAT Latitude of origin > > >>> +lat_1 = TRUELAT1 Latitude of first standard parallel > > >>> +lat_2 = TRUELAT2 Latitude of second standard parallel > > >>> +lon_0 = CEN_LON Central meridian > > >>> > > >>> proj strings are defined by the proj4 libary. It's website listed > above > > >>> and the associated mailing lists or gis stackexchange would be the > > >>> places to get help on it. > > >>> https://lists.osgeo.org/mailman/listinfo/metacrs > > >>> > > >>> It often helps to browse similar projections on > > >>> http://spatialreference.org/ > > >>> http://epsg.io/ > > >>> > > >>> Enjoy, > > >>> Alex > > >>> > > >>> > > >> > > >> > > > > > > _______________________________________________ > > > R-sig-Geo mailing list > > > R-sig-Geo@r-project.org > > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > -- > > Roger Bivand > > Department of Economics, Norwegian School of Economics, > > Helleveien 30, N-5045 Bergen, Norway. > > voice: +47 55 95 93 55; fax +47 55 95 91 00 > > e-mail: roger.biv...@nhh.no > > http://orcid.org/0000-0003-2392-6140 > > https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en > > http://depsy.org/person/434412 > > _______________________________________________ > > R-sig-Geo mailing list > > R-sig-Geo@r-project.org > > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > -- > Dr. Michael Sumner > Software and Database Engineer > Australian Antarctic Division > 203 Channel Highway > Kingston Tasmania 7050 Australia > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- Agustín Camacho Guerrero. Doutor em Zoologia. Laboratório de Herpetologia, Departamento de Zoologia, Instituto de Biociências, USP. Rua do Matão, trav. 14, nº 321, Cidade Universitária, São Paulo - SP, CEP: 05508-090, Brasil. [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo
