Displaying 20 results from an estimated 2000 matches similar to: "Drawing (lon,lat) coordinates onto the image of a world"
2008 Jul 09
0
"Rotated Lat-Lon" projection in mapproj
Hi,
I'm trying to plot a field obtained from the atmospheric model WRF-NMM
which uses a "Rotated Lat-Lon? map projection.
The WRF documentation mentions that:
? Rotates the earth's lat/lon grid such that the intersection of the
equator and prime meridian is at the center of the model domain.
? Within the rotated framework the grid spacing is constant, but in an
earth-relative
2011 Nov 08
1
from points in Lon/Lat to physical distance in dist class
Dear R-listers,
Here, I would like to hearing helps from you.
I have GPS data (multiple points in the geographic scale) in
longitude/latitude. I intend to calculate
distance (in kilometer) among such points and output the distance matrix in
dist class.
I have gotten some progress, but I still can not get final goal. Could
please give me any directions/advice?
This email cc. to Mr. Pierre, the
2011 Mar 21
1
Lat Lon NetCDF subset
Hi,
I'm trying to read a subset of a netcdf file into R, but although I'm
relatively experienced using R, I'm still new to netCDF files, so this may
be a very simple/stupid question!
I've included an example of the type of file I'm looking at here.
www.met.reading.ac.uk/~swp06hg/ccd1983_01-dk1_20.nc (~7Mb)
It's a 2D array of the variable CCD along with its lat and
2008 Oct 07
2
masking a regular lat/lon grid to extract map boundaries
Dear R-helpers,
I have lat/lon coordinates of regularly spaced grid points, about 4Km
apart, covering the entire US continental region.
I would like to mask this rectangular grid in order to extract all and
only the grid points within a specific region. Today I want to
extract Montana, say, from this grid, and I am hoping to somehow use
the returned value of the function
2007 Apr 04
5
how to image.plot a XY grid file into a lat-lon map
Hi All,
I have a netcdf gridded file with LCC projection. I can easily use
image.plot to visualize it. However, as the axises are in X,Y, not Lat and
Lon, I could not add state or country maps onto it (or lat lon information).
I do have a grid2d file that describes the lat and lon for each (X,Y) grid,
but the lat and lon are not regularly spaced, so I could not use image.plot.
Does anyone know
2010 Jan 05
3
R matching lat/lon pairs from two datasets?
Hello,
I am trying to match lat/lon from one dataset with the lat/lon from a
second dataset and use that rows data for calculations. I am using
match, but this is finding the first match and not comparing the pair,
how can I determine if the lat/lon are the same? See example below. Is
there a better way to determine to a matching pair of lat/lon values?
Example Datasets:
> data2
2017 Aug 28
0
Extracting subset from netCDF file using lat/lon and converting into .csv in R
Two questions:
1. Is the order of the dimensions shown what is shown if you look at str(ncin) - I mean shown at the end where it describes the variable and its dimensions?
2. Is you problem how to subset the netcdf file, how to write to the .csv file, or both?
-Roy
> On Aug 28, 2017, at 2:21 PM, Eeusha Nafi <eshad002 at gmail.com> wrote:
>
> I have a series of nertCDF files
2017 Aug 28
3
Extracting subset from netCDF file using lat/lon and converting into .csv in R
I have a series of nertCDF files containing global data for a particular
variable, e.g. tmin/tmax/precipiation/windspeed/relative
humuidity/radiation etc. I get the following information when using
*nc_open* function in R:
datafile: https://www.dropbox.com/s/xpo7zklcmtm3g5r/gfdl_preci.nc?dl=0
File gfdl_preci.nc (NC_FORMAT_NETCDF4_CLASSIC):
1 variables (excluding dimension variables):
2006 Feb 09
1
converting lat-long coordinates to Albers Conical Equal Area coordinates
####################################################################################
We have used maptools to construct state, county, township, census-tract,
and zipcode
level R maps with an Albers Conical Equal Area projection. We would like
to be able to
plot the location of weather stations or other point locations on the
maps. The data
the point locations are in latitude-longitude units
2008 Jun 26
1
Layout() coordinates and drawing lines / segments
Hello,
I am trying to wrap my head around the coordinates systems associated with
the layout() function ...with the end goal of simply drawing a decorative
line in the upper margin of my figure, which is composed of three plots.
My output is defined as this:
----------------------------------------------------------------------------
postscript("out.ps", horizontal=FALSE,
2018 May 22
0
How to average values from grid cells with coordinates
Hi Jim,
Thanks. It works. I now have more complex problems. If at each blackcell,
there are two variables such as pop and mood. For each variable, there are
daily records in one year, so 365 records for pop and 365 records for mood.
The averaged values for the redcells should be daily records too. What kind
of format do you recommend for this problem? Right now, I just get the
latitudes and
2018 May 20
1
How to average values from grid cells with coordinates
Hi lily,
It's not too hard to do it using dataframes. Getting the indexing
right is usually that hardest part:
# these values are the centers of the black cells
lat<-rep(28:38,11)
lon<-rep(98:108,each=11)
pop<-sample(80:200,121)
# just use the data.frame function
blackcells<-data.frame(lat=lat,lon=lon,pop=pop)
plot(0,type="n",xlim=c(97.5,108.5),ylim=c(27.5,38.5),
2018 May 19
0
How to average values from grid cells with coordinates
Hi lily,
You could also create "blackcells" as a dataframe (which is itself a
type of list). I used a list as I thought it would be a more general
solution if there were different numbers of values for different grid
cells. The use of 1 for the comparison was due to the grid increments
being 1. If you had larger or smaller grid increments, you would use
the grid increment size for the
2018 May 16
0
How to average values from grid cells with coordinates
Hi lily,
There are one or two assumptions to be made here. First is that the
latitude and longitude values of the "black" cells are equally spaced
as in your illustration. Second, that all latitude and longitude
values for the "red" cells fall at the corners of four "black" cells.
You can get the four "black" cells by finding the lat/lon values that
are
2004 Jun 01
1
converting text coordinates to decimal degrees
I receive GPS readings in a text string such as
"0121.6723S 03643.6893E" and need the coordinates as
decimal degrees in two separate variables: "-1.361205"
and "36.728155". How do I do this in R?
mikkel
2018 May 16
5
How to average values from grid cells with coordinates
Hi R users,
I have a question about data processing. I have such a dataset, while each
black grid cell has a few attributes and the corresponding attribute
values. The latitude and longitude of the center of each grid cell are
given also.
Then I want to average the attribute values from four adjacent grid cells
to get the average value for the center of each red grid cell. Thus, there
are the
2010 Jan 27
2
plotting the coordinates versus dates
Hello!
I have a dataset with the dates and positions - Lat and Long columns
How do I make a scatter plot?
Do I have to cbind to combine the Lat and Long columns?
Any suggestions will be much appreciated!
Thank you
Julia
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2005 Sep 14
4
Converting coordinates to actual distances
Hello,
I've been searching for a method of converting Lat/Lon decimal
coordinates into actual distances between points, and taking into
account the curvature of the earth. Is there such a package in R? I've
looked at the GeoR package, but this does not seem to contain what I am
looking for. Ideally the output would be a triangular matrix of
distances.
Thanks in advance,
Paul Brewin
2006 Feb 01
1
Gauss-Krüger coordinates system
Dear All,
I need to convert some Northing-Easting coordinates from the Gauss-Krüger system into latitude-longitude.
Any suggestions on how to do it?
Regards,
Marco
Marco Giannitrapani
Statistical Consultant
Tel: +44151373 5945
Email:
Internet: http://www.shell.com
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2007 Sep 02
1
how to sub-sample a variable on another file coordinates
Hello 'R' Users,
I have a monthly mean CO2 necdf data file defined on 1x1 lat by lon
coordinate. I want to sub-sample this variable CO2 on the coordinates
of another ASCII data file. The coordinates of another ASCII data file are
as:
-24.01 152.06 -18.58 150.19 -13.46 148.35 -8.29 147.03 -3.14 146.19 1.53
145.59 7.08 145.33 12.25 145.02 17.46 144.31 22.44 142.35 27.53 141.26 33.04