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| author | rsc <devnull@localhost> | 2004-04-21 22:19:33 +0000 |
|---|---|---|
| committer | rsc <devnull@localhost> | 2004-04-21 22:19:33 +0000 |
| commit | 28994509cc11ac6a5443054dfae1fedfb69039bc (patch) | |
| tree | 9d5adcd11af2708db0ecc246e008c308ca0f97d4 /src/cmd/map/libmap/mollweide.c | |
| parent | a01e58366c54804f15f84d6e21d13f2e4080977a (diff) | |
| download | plan9port-28994509cc11ac6a5443054dfae1fedfb69039bc.tar.gz plan9port-28994509cc11ac6a5443054dfae1fedfb69039bc.tar.bz2 plan9port-28994509cc11ac6a5443054dfae1fedfb69039bc.zip | |
Why not?
Diffstat (limited to 'src/cmd/map/libmap/mollweide.c')
| -rw-r--r-- | src/cmd/map/libmap/mollweide.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/src/cmd/map/libmap/mollweide.c b/src/cmd/map/libmap/mollweide.c new file mode 100644 index 00000000..3284c495 --- /dev/null +++ b/src/cmd/map/libmap/mollweide.c @@ -0,0 +1,25 @@ +#include <u.h> +#include <libc.h> +#include "map.h" + +static int +Xmollweide(struct place *place, double *x, double *y) +{ + double z; + double w; + z = place->nlat.l; + if(fabs(z)<89.9*RAD) + do { /*newton for 2z+sin2z=pi*sin(lat)*/ + w = (2*z+sin(2*z)-PI*place->nlat.s)/(2+2*cos(2*z)); + z -= w; + } while(fabs(w)>=.00001); + *y = sin(z); + *x = - (2/PI)*cos(z)*place->wlon.l; + return(1); +} + +proj +mollweide(void) +{ + return(Xmollweide); +} |