converting lat-long coordinates to Albers Conical Equal Area coordinates

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converting lat-long coordinates to Albers Conical Equal Area coordinates

jatwood@montana.edu
####################################################################################
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 and we must convert the
coordinates
to the Albers Conical Equal Area coordinates.

However, as of yet, we have not been able to obtain satisfactory results
using mapproj.
Given the specs below can someone please tell us how to use mapproj (or
some other R
library) to convert lat-long coordinates into the appropriate Albers
Conical Equal Area
coordinates?

Thanks in advance
Joe Atwood
Montana State University
[hidden email]

####################################################################################
The material at the bottom of this message is the metadata from
the shapefile we are using (as created in Arc-GIS).
####################################################################################

-----------------------------------
Horizontal coordinate system
Projected coordinate system name: NAD_1927_Albers
Geographic coordinate system name: GCS_North_American_1927
Details
Map Projection Name: Albers Conical Equal Area
Standard Parallel: 29.500000
Standard Parallel: 45.500000
Longitude of Central Meridian: -96.000000
Latitude of Projection Origin: 23.000000
False Easting: 0.000000
False Northing: 0.000000


Planar Coordinate Information
Planar Distance Units: meters
Coordinate Encoding Method: coordinate pair
Coordinate Representation
Abscissa Resolution: 0.008192
Ordinate Resolution: 0.008192


Geodetic Model
Horizontal Datum Name: North American Datum of 1927
Ellipsoid Name: Clarke 1866
Semi-major Axis: 6378206.400000
Denominator of Flattening Ratio: 294.978698
_________________

Bounding coordinates
Horizontal
In decimal degrees
West: -127.889829
East: -65.349890
North: 51.606167
South: 22.862978
In projected or local coordinates
Left: -2356341.706499
Right: 2257925.009693
Top: 3172647.320063
Bottom: 268329.067476

###################################################################################

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Re: converting lat-long coordinates to Albers Conical Equal Area coordinates

Roger Bivand
On Thu, 9 Feb 2006, jatwood wrote:

> ####################################################################################
> 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 and we must convert the
> coordinates
> to the Albers Conical Equal Area coordinates.
>
> However, as of yet, we have not been able to obtain satisfactory results
> using mapproj.
> Given the specs below can someone please tell us how to use mapproj (or
> some other R
> library) to convert lat-long coordinates into the appropriate Albers
> Conical Equal Area
> coordinates?

Please look in spproj on the r-spatial sourceforge site, entrance via the
Spatial Task View on CRAN. Look for function project() and visit the proj4
website to work out the arguments needed.

If this isn't sufficient, please continue this thread on the R-sig-geo
mailing list.

>
> Thanks in advance
> Joe Atwood
> Montana State University
> [hidden email]
>
> ####################################################################################
> The material at the bottom of this message is the metadata from
> the shapefile we are using (as created in Arc-GIS).
> ####################################################################################
>
> -----------------------------------
> Horizontal coordinate system
> Projected coordinate system name: NAD_1927_Albers
> Geographic coordinate system name: GCS_North_American_1927
> Details
> Map Projection Name: Albers Conical Equal Area
> Standard Parallel: 29.500000
> Standard Parallel: 45.500000
> Longitude of Central Meridian: -96.000000
> Latitude of Projection Origin: 23.000000
> False Easting: 0.000000
> False Northing: 0.000000
>
>
> Planar Coordinate Information
> Planar Distance Units: meters
> Coordinate Encoding Method: coordinate pair
> Coordinate Representation
> Abscissa Resolution: 0.008192
> Ordinate Resolution: 0.008192
>
>
> Geodetic Model
> Horizontal Datum Name: North American Datum of 1927
> Ellipsoid Name: Clarke 1866
> Semi-major Axis: 6378206.400000
> Denominator of Flattening Ratio: 294.978698
> _________________
>
> Bounding coordinates
> Horizontal
> In decimal degrees
> West: -127.889829
> East: -65.349890
> North: 51.606167
> South: 22.862978
> In projected or local coordinates
> Left: -2356341.706499
> Right: 2257925.009693
> Top: 3172647.320063
> Bottom: 268329.067476
>
> ###################################################################################
>
> ______________________________________________
> [hidden email] mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>

--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: [hidden email]

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Roger Bivand
Department of Economics
NHH Norwegian School of Economics
Helleveien 30
N-5045 Bergen, Norway