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diff --git a/man/2/geodesy b/man/2/geodesy new file mode 100644 index 00000000..73c5331a --- /dev/null +++ b/man/2/geodesy @@ -0,0 +1,146 @@ +.TH GEODESY 2 +.SH NAME +geodesy \- Geodesy module +.SH SYNOPSIS +.EX +include "geodesy.m"; +geodesy := load Geodesy Geodesy->PATH; + +# easting, northing +Eano: adt{ + e: real; + n: real; +}; + +# latitude, longitude in radians +Lalo: adt{ + la: real; + lo: real; +}; + +OSGB36, Ireland65, ED50, WGS84, ITRS2000, ETRS89: con iota; + +Natgrid, IrishNatgrid, UTMEur, UTM: con iota; + +init: fn(d: int, t: int, z: int); +format: fn(d: int, t: int, z: int); +os2en: fn(s: string): (int, Eano); +en2os: fn(en: Eano): string; +str2lalo: fn(s: string): (int, Lalo); +lalo2str: fn(lalo: Lalo): string; +str2en: fn(s: string): (int, Eano); +en2lalo: fn(en: Eano): Lalo; +lalo2en: fn(lalo: Lalo): Eano; +datum2datum: fn(lalo: Lalo, f: int, t: int): Lalo; +.EE +.SH DESCRIPTION +.B Geodesy +provides routines to deal with (some) terrestrial coordinate systems. +.PP +Eastings and northings are defined by the +.B Eano +adt and are measured in metres and latitude and longitude (which should be in radians) by the +.B Lalo +adt. Latitude is in the range -π/2 to π/2 radians and longitude in the +range -π to π radians. +.PP +.B OSGB36 +(Ordnance Survey Great Britain 1936), +.B Ireland65 +(Ireland 1965), +.B ED50 +(European Datum 1950), +.B WGS84 +(World Geodetic System 1984), +.B ITRS2000 +(International Terrestrial Reference System 2000), and +.B ETRS89 +(European Terrestrial Reference System 1989) are the current datums defined. Helmert transformations are used +to convert between them. Note that +.B Ireland65 +and +.B ED50 +are currently not supported and +.B WGS84 +and +.B ITRS2000 +are considered equivalent. +.PP +.B Natgrid +(National Grid), +.B IrishNatgrid +(Irish National Grid), +.B UTMEur +(European Universal Transverse Mercator), and +.B UTM +(Universal Transverse Mercator) are the current transverse Mercator projections supported. +.PP +The following functions are provided +.TP +.B init +The module should always be initialized first. The parameters are +the required datum (default WGS84), transverse Mercator projection (default Natgrid) and UTM zone (default 30) if appropriate. Negative values or out of range values are +ignored. +.TP +.B format +Parameters as above. Alters the current settings at any time though care +must be taken to ensure existing coordinates are still treated as in their +original form. +.TP +.B os2en +Converts an Ordnance Survey National Grid reference to an easting, northing. +The formats XYen, XYeenn, XYeeennn, XYeeeennnn, XYeeeeennnnn, eenn, +eeennn, eeeennnn, eeeeennnnn and eeeeeennnnnn are allowed. Here X and +Y are upper case letters, e is an easting digit and n is a northing digit. The +reference can therefore be rounded to the nearest decakilometre, kilometre, +hectometre, decametre or metre. The first element of the returned tuple is zero +if the string has an incorrect format. +.TP +.B en2os +Converts an easting, northing to an OS reference in the form XYeeeeennnnn +as above. +.TP +.B str2lalo +Converts a latitude/longitude string to a latitude, longitude. The string +may have the formats deg[N|S], deg:min[N|S] or deg:min:sec[N|S] for +latitude, deg[E|W], deg:min[E|W] or deg:min:sec[E|W] for longitude. The +latitude must come first, then optional white space, then the longitude. +Degrees, minutes and seconds may be integer or real. Format errors +are indicated as in +.B os2en. +.TP +.B lalo2str +Converts a latitude, longitude to string format as above. Seconds are given +to two decimal places. +.TP +.B str2en +Converts a string in OS or latitude/longitude format as above to an easting, northing. +Format errors indicated as in +.B os2en. +.TP +.B en2lalo +Converts an easting, northing to latitude, longitude using the current transverse +Mercator projection.If the latter is +.B UTM +or +.B UTMEur +the current zone setting will be used. +.TP +.B lalo2en +Converts latitude, longitude to an easting, northing using the current transverse +Mercator projection. +.TP +datum2datum +Approximate (Helmert) transformation of a latitude, longitude between any of +.B OSGB36, +.B WGS84, +.B ITRS2000 +or +.B ETRS89. +The `from' datum appears first in the parameter list. +.SH SOURCE +.B /module/math/geodesy.m +.br +.B /appl/math/geodesy.b +.SH BUGS +The module is heavily biased towards Great Britain. |