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: http://xray.sai.msu.ru/~ivan/gmt/man/mapproject.html
Дата изменения: Fri Mar 19 17:20:11 1999 Дата индексирования: Tue Oct 2 08:21:30 2012 Кодировка: Поисковые слова: south pole |
mapproject - Forward and Inverse map transformation of 2-D coordinates
mapproject infiles -Jparameters -Rwest/east/south/north[r] [ -C ] [ -Dc|i|m|p ] [ -F[k|m|n] ] [ -H[nrec] ] [ -I ] [ -M[flag] ] [ -S ] [ -V ] [ -: ] [ -bi[s][n] ] [ -bo[s] ]
mapproject reads (longitude, latitude) positions from infiles [or standard input] and computes (x,y) coordinates using the specified map projection and scales. Optionally, it can read (x,y) positions and compute (longitude, latitude) values doing the inverse transformation. This can be used to transform linear (x,y) points obtained by digitizing a map of known projection to geographical coordinates. Additional data fields are permitted after the first 2 columns which must have (longitude,latitude) or (x,y). See option -: on how to read (latitude,longitude) files. No space between the option flag and the associated arguments. Use upper case for the option flags and lower case for modifiers. infiles Data file(s) to be transformed. If not given, standard input is read. -J Selects the map projection. The following character determines the projection. If the character is upper case then the argument(s) supplied as scale(s) is interpreted to be the map width (or axis lengths) in inch, else the scale argument(s) is the map scale (see its definition for each projection). Choose one of the following projections (The E or C after projection names stands for Equal-Area and Conformal, respectively): CYLINDRICAL PROJECTIONS: -Jclon0/lat0/scale or -JClon0/lat0/width (Cassini) Give projection center and scale (1:xxxx or inch/degree). -Jjlon0/scale or -JJlon0/width (Miller Cylindrical Projection) Give the central meridian and scale (1:xxxx or inch/degree). -Jmparameters (Mercator [C]). Specify one of: -Jmscale or -JMwidth Give scale along equator (1:xxxx or inch/degree). -Jmlon0/lat0/scale or -JMlon0/lat0/width Give central meridian, standard latitude and scale along parallel (1:xxxx or inch/degree). -Joparameters (Oblique Mercator [C]). Specify one of: -Joalon0/lat0/azimuth/scale or -JOalon0/lat0/azimuth/width Set projection center, azimuth of oblique equator, and scale. -Joblon0/lat0/lon1/lat1/scale or -JOblon0/lat0/lon1/lat1/scale Set projection center, another point on the oblique equator, and scale. -Joclon0/lat0/lonp/latp/scale or -JOclon0/lat0/lonp/latp/scale Set projection center, pole of oblique projection, and scale. Give scale along oblique equator (1:xxxx or inch/degree). -Jqlon0/scale or -JQlon0/width (Equidistant Cylindrical Projection (Plate Carree)) Give the central meridian and scale (1:xxxx or inch/degree). -Jtlon0/scale or -JTlon0/width (TM - Transverse Mercator [C]) Give the central meridian and scale (1:xxxx or inch/degree). -Juzone/scale or -JUzone/width (UTM - Universal Transverse Mercator [C]) Give the zone number and scale (1:xxxx or inch/degree). Use negative zone numbers for the southern hemisphere. -Jylon0/lats/scale or -JYlon0/lats/width (Basic Cylindrical Projections [E]) Give the central meridian, standard parallel, and scale (1:xxxx or inch/degree). The standard parallel is typically one of these (but can be any value): 45 - The Peters projection 37.4 - The Trystan Edwards projection 30 - The Behrman projection 0 - The Lambert projection AZIMUTHAL PROJECTIONS: -Jalon0/lat0/scale or -JAlon0/lat0/width (Lambert [E]). lon0/lat0 specifies the projection center. Give scale as 1:xxxx or radius/lat, where radius is distance in inch from origin to the oblique latitude lat. -Jelon0/lat0/scale or -JElon0/lat0/width (Equidistant). lon0/lat0 specifies the projection center. Give scale as 1:xxxx or radius/lat, where radius is distance in inch from origin to the oblique latitude lat. -Jflon0/lat0/horizon/scale or -JFlon0/lat0/horizon//width (Gnomonic). lon0/lat0 specifies the projection center. horizon specifies the max distance from projection center (in degrees, < 90). Give scale as 1:xxxx or radius/lat, where radius is distance in inch from origin to the oblique latitude lat. -Jglon0/lat0/scale or -JGlon0/lat0/width (Orthographic). lon0/lat0 specifies the projection center. Give scale as 1:xxxx or radius/lat, where radius is distance in inch from origin to the oblique latitude lat. -Jslon0/lat0/scale or -JSlon0/lat0/width (General Stereographic [C]) lon0/lat0 specifies the projection center. Give scale as 1:xxxx or radius/lat, where radius is distance in inch from origin to the oblique latitude lat. CONIC PROJECTIONS: -Jblon0/lat0/lat1/lat2/scale or -JBlon0/lat0/lat1/lat2/width (Albers [E]) Give projection center, two standard parallels, and scale (1:xxxx or inch/degree). -Jllon0/lat0/lat1/lat2/scale or -JLlon0/lat0/lat1/lat2/width (Lambert [C]) Give origin, 2 standard parallels, and scale along these (1:xxxx or inch/degree). MISCELLANEOUS PROJECTIONS: -Jhlon0/scale or -JHlon0/width (Hammer [E]) Give the central meridian and scale along equator (1:xxxx or inch/degree). -Jilon0/scale or -JIlon0/width (Sinusoidal [E]) Give the central meridian and scale along equator (1:xxxx or inch/degree). -Jklon0/scale or -JKlon0/width (Eckert VI [E]) Give the central meridian and scale along equator (1:xxxx or inch/degree). -Jnlon0/scale or -JNlon0/width (Robinson) Give the central meridian and scale along equator (1:xxxx or inch/degree). -Jrlon0/scale -JRlon0/width (Winkel Tripel) Give the central meridian and scale along equator (1:xxxx or inch/degree). -Jwlon0/scale or -JWlon0/width (Mollweide [E]) Give the central meridian and scale along equator (1:xxxx or inch/degree). NON-GEOGRAPHICAL PROJECTIONS: -Jpscale or -JPwidth (Linear projection for polar (theta,r) coordinates) Give scale in inch/r-unit. -Jxx-scale[/y-scale] or -JXwidth[/height] scale [or width] can be any of the following 3 types: -Jxscale - Regular linear scaling. -Jxscalel - Take log10 of values before scaling. -Jxscaleppower - Raise values to power before scaling. Give x-scale in inch/x-unit and y-scale in inch/y-unit. (y-scale = x-scale if not specified separately). Use negative scale(s) to reverse the direction of an axis (e.g., to have y be positive down). Append d if x and y are geographical coordinates in degrees. Default axes lengths (see gmtdefaults) can be invoked using -JXh (for landscape); -JXv (for portrait) will swap the x- and y-axes lengths. The GMT default unit for this installation is inch. However, you may change this by editing your .gmtdefaults file(s) (run gmtdefaults to create one if you don't have it). The ellipsoid used in the map projections is user-definable by editing the .gmtdefaults file in your home directory. 13 commonly used ellipsoids and a spheroid are currently supported, and users may also specify their own ellipsoid parameters (see man gmtdefaults for more details). GMT default is WGS-84. -R west, east, south, and north specify the Region of interest. To specify boundaries in degrees and minutes [and seconds], use the dd:mm[:ss] format. Append r if lower left and upper right map coordinates are given instead of wesn.
infile(s) input file(s) with 2 or more columns. If no file(s) is given, mapproject will read standard input. -C Set center of projected coordinates to be at map projection center [Default is lower left corner]. -D Temporarily override MEASURE_UNIT and use c (cm), i (inch), m (meter), or p (points) instead. -F Force 1:1 scaling, i.e., output (or input, see -I) data are in actual projected meters. To specify other units, append k (km), m (mile),n (nautical mile), i (inch), c (cm), or p (points). Without -F, the output (or input, see -I) are in the units specified by MEASURE_UNIT (but see -D). -H Input file(s) has Header record(s). Number of header records can be changed by editing your .gmtdefaults file. If used, GMT default is 1 header record. -I Do the Inverse transformation, i.e. get (longitude,latitude) from (x,y) data. -M Multiple segment file(s). Segments are separated by a special record. For ASCII files the first character must be flag [Default is '>']. For binary files all fields must be NaN. -S Suppress points that fall outside the region. -V Selects verbose mode, which will send progress reports to stderr [Default runs "silently"]. -: Toggles between (longitude,latitude) and (latitude,longitude) input/output. [Default is (longitude,latitude)]. -bi Selects binary input. Append s for single precision [Default is double]. Append n for the number of columns in the binary file(s). [Default is 2 input columns] -bo Selects binary output. Append s for single precision [Default is double].
To transform a file with (longitude,latitude) into (x,y) positions in inch on a Mercator grid for a given scale of 0.25 inch per degree, run mapproject lonlatfile -R20/50/12/25 -Jm0.25i > xyfile To transform several 2-column, binary, double precision files with (latitude,longitude) into (x,y) positions in inch on a Transverse Mercator grid (central longitude 75W) for scale = 1:500000 and suppress those points that would fall outside the map area, run mapproject tracks.* -R-80/-70/20/40 -Jt-75/1:500000 -: -S -bo -bi2 > tmfile.b
The rectangular input region set with -R will in general be mapped into a non-rectangular grid. Unless -C is set, the leftmost point on this grid has xvalue = 0.0, and the lowermost point will have yvalue = 0.0. Thus, before you digitize a map, run the extreme map coordinates through mapproject using the appropriate scale and see what (x,y) values they are mapped onto. Use these values when setting up for digitizing in order to have the inverse transformation work correctly, or alternatively, use awk to scale and shift the (x,y) values before transforming.
gmtdefaults, gmt, project
Snyder, J. P., 1987, Map Projections - A Working Manual, U.S. Geological Survey Prof. Paper 1395.