From 87f150f1d9e634f83cb8945abce2577a46bd7ed7 Mon Sep 17 00:00:00 2001 From: Frank Warmerdam Date: Fri, 14 Oct 2005 13:15:08 +0000 Subject: New git-svn-id: http://svn.osgeo.org/metacrs/proj/trunk@1305 4e78687f-474d-0410-85f9-8d5e500ac6b2 --- html/man_pj_init.html | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 159 insertions(+) create mode 100644 html/man_pj_init.html (limited to 'html/man_pj_init.html') diff --git a/html/man_pj_init.html b/html/man_pj_init.html new file mode 100644 index 00000000..e46a5a03 --- /dev/null +++ b/html/man_pj_init.html @@ -0,0 +1,159 @@ +Content-type: text/html + +Manpage of PJ_INIT + +

PJ_INIT

+Section: Misc. Reference Manual Pages (3U)
Updated: 2001/04/05 Rel. 4.4
Index +Return to Main Contents

+ + + + +

NAME

+ +pj_init - initialize cartographic projection +
+ +pj_init_plus - initialize cartographic projection +
+ +pj_fwd - forward cartographic projection +
+ +pj_inv - inverse cartographic projection +
+ +pj_transform - transform between coordinate systems +
+ +pj_free - de-initialize projection + +

SYNOPSIS

+ +

+#include <proj_api.h>
+
+projPJ pj_init(int argc, char **argv)
+
+projPJ pj_init_plus(const char *defn)
+
+projUV pj_fwd(projUV val, projPJ proj)
+
+projUV pj_inv(projUV val, projPJ proj)
+
+int pj_transform(projPJ src_cs, projPJ dst_cs, long point_count, 
+                 double *x, double *y, double *z)
+               
+void pj_free(projPJ proj)
+
+

DESCRIPTION

+ +Procedure pj_init selects and initializes a cartographic projection +with its argument control parameters. +Argc is the number of elements in the array of control strings +argv that each contain individual cartographic control keyword +assignments (+ proj arguments). +The list must contain at least the proj=projection and +Earth's radius or elliptical parameters. +If the initialization of the projection is successful a valid +address is returned otherwise a NULL value. +

+The pj_init_plus function operates similarly to pj_init but +takes a single string containing the definition, with each parameter +prefixed with a plus sign. For example "+proj=utm +zone=11 +ellps=WGS84". +

+Once initialization is performed either forward or inverse +projections can be performed with the returned value of pj_init +used as the argument proj. +The argument structure projUV values u and v contain +respective longitude and latitude or x and y. +Latitude and longitude are in radians. +If a projection operation fails, both elements of projUV are +set to HUGE_VAL (defined in math.h). +

+Note: all projections have a forward mode, but some do not have +an inverse projection. +If the projection does not have an inverse the projPJ structure element +inv will be NULL. +

+The pj_transform function may be used to transform points between +the two provided coordinate systems. In addition to converting between +cartographic projection coordinates and geographic coordinates, this function +also takes care of datum shifts if possible between the source and destination +coordinate system. Unlike pj_fwd and pj_inv it is also allowable +for the coordinate system definitions (PJ *) to be geographic coordinate +systems (defined as +proj=latlong). The x, y and z arrays +contain the input values of the points, and are replaced with the output +values. The function returns zero on success, or the error number (also in +pj_errno) on failure. +

+Memory associated with the projection may be freed with pj_free. + +

EXAMPLE

+ +The following program reads latitude and longitude values in decimal +degress, performs Mercator projection with a Clarke 1866 ellipsoid and +a 33° latitude of true scale and prints the projected +cartesian values in meters: +

+
+#include <proj_api.h>
+
+main(int argc, char **argv) {
+        char *args[] = { "proj=merc", "ellps=clrk66", "lat_ts=33" };
+        projUV p;
+        projPJ pj;
+
+        if (!(pj = pj_init(3, args)))
+           exit(1);
+        while (scanf("%lf %lf", &p.v, &p.u) == 2) {
+           p.u *= DEG_TO_RAD;
+           p.v *= DEG_TO_RAD;
+           p = pj_fwd(p, pj);
+           printf("%.2f\t%.2f\n", p.u, p.v);
+        }
+        exit(0);
+} 
+

+

+ + +

LIBRARY

+ +libproj.a - library of projections and support procedures + +

HOME PAGE

+ +http://www.remotesensing.org/proj +

+ +

+This document was created by +man2html, +using the manual pages.
+Time: 13:14:22 GMT, October 14, 2005 + + -- cgit v1.2.3