[GRASS-CVS] hamish: grass/src/raster/r.coin/cmd prnt_entry.c, 1.1.1.1, 1.2

[grass at intevation.de]

Author: hamish

Update of /grassrepository/grass/src/raster/r.coin/cmd
In directory doto:/tmp/cvs-serv23370/grass/src/raster/r.coin/cmd

Modified Files:
	prnt_entry.c 
Log Message:
more precise conversions to feet, square miles and acres
  (merge from 6.3 HEAD)


Index: prnt_entry.c
===================================================================
RCS file: /grassrepository/grass/src/raster/r.coin/cmd/prnt_entry.c,v
retrieving revision 1.1.1.1
retrieving revision 1.2
diff -u -d -r1.1.1.1 -r1.2
--- prnt_entry.c	29 Dec 1999 15:11:06 -0000	1.1.1.1
+++ prnt_entry.c	20 Nov 2007 03:06:17 -0000	1.2
@@ -1,8 +1,10 @@
 #include "coin.h"
 
 #define F_CTOK(C)	((double)(C))/1000000.0
-#define F_CTOM(C)	F_CTOK(C) *   0.3861
-#define F_CTOA(C)	F_CTOK(C) * 247.1000
+	/* sq km -> sq miles = 1000^2 / (0.0254 * 12 * 5280)^2 */
+#define F_CTOM(C)	F_CTOK(C) * 0.386102158542446
+	/* sq km -> acres = sq miles * 640 */
+#define F_CTOA(C)	F_CTOK(C) * 247.105381467165
 #define F_CTOH(C)	F_CTOK(C) * 100.0000
 
 #define F_CTOP(C,R) ((int)R) ? (double)C / (double)R * 100.0 : 0.0
@@ -26,7 +28,7 @@
 	case 'k': 
 		print_area(F_CTOK(area));
 		break;
-	case 'm': 
+	case 'm':  /* square miles */
 		print_area(F_CTOM(area));
 		break;
 	case 'p': 
@@ -40,7 +42,7 @@
 		row_total(Rndex,1,&total_count,&total_area);
 		print_percent(F_CTOY(area,total_area));
 		break;
-	default:  
+	default:  /* case 'c' */ 
 		fprintf(dumpfile," %9ld |", count);
 		break;
     }