diff --git a/include/prototypes.h b/include/prototypes.h
index 73d01ef1..ef2ad0dc 100644
--- a/include/prototypes.h
+++ b/include/prototypes.h
@@ -281,8 +281,6 @@ extern int logreopen(void);
 extern void logerror(char *, ...) ATTRIBUTE((format (printf, 1, 2)));
 /* more in misc.h */
 /* mapdist.c */
-extern int diffx(int, int);
-extern int diffy(int, int);
 extern int deltax(int, int);
 extern int deltay(int, int);
 extern int mapdist(int, int, int, int);
diff --git a/src/lib/common/mapdist.c b/src/lib/common/mapdist.c
index cac702f4..50d90c00 100644
--- a/src/lib/common/mapdist.c
+++ b/src/lib/common/mapdist.c
@@ -41,34 +41,6 @@
 #include "optlist.h"
 #include "prototypes.h"
 
-int
-diffx(int x1, int x2)
-{
-    int dx;
-
-    dx = x1 - x2;
-    dx = dx % WORLD_X;
-    if (dx > WORLD_X / 2)
-	dx = dx - WORLD_X;
-    if (dx < -WORLD_X / 2)
-	dx = dx + WORLD_X;
-    return dx;
-}
-
-int
-diffy(int y1, int y2)
-{
-    int dy;
-
-    dy = y1 - y2;
-    dy = dy % WORLD_Y;
-    if (dy > WORLD_Y / 2)
-	dy = dy - WORLD_Y;
-    if (dy < -WORLD_Y / 2)
-	dy = dy + WORLD_Y;
-    return dy;
-}
-
 int
 deltax(int x1, int x2)
 {
diff --git a/src/lib/subs/satmap.c b/src/lib/subs/satmap.c
index cc4b06db..3e37dceb 100644
--- a/src/lib/subs/satmap.c
+++ b/src/lib/subs/satmap.c
@@ -177,15 +177,8 @@ satmap(int x, int y, int eff, int range, int flags, int type)
 	    }
 	    /* If we are imaging *and* drawing the map */
 	    if ((flags & P_I) && (type == EF_BAD)) {
-		/* Figure out where to put the ship */
-		/* First, figure out the distance from the two */
-		rx = diffx((int)ship.shp_x, x);
-		ry = diffy((int)ship.shp_y, y);
-		/* Next, determine which direction to add it to the center */
-		/* We can only do this if imaging and we have gotten the center
-		   up above by imaging the sectors. */
-		rx = deltax(x, ns.range.lx) + rx;
-		ry = deltay(y, ns.range.ly) + ry;
+		rx = deltx(&ns.range, ship.shp_x);
+		ry = delty(&ns.range, ship.shp_y);
 		/* &~0x20 makes it a cap letter */
 		rad[ry][rx] = (*mchr[(int)ship.shp_type].m_name) & ~0x20;
 	    }
@@ -230,15 +223,8 @@ satmap(int x, int y, int eff, int range, int flags, int type)
 	    }
 	    /* If we are imaging *and* drawing the map */
 	    if ((flags & P_I) && (type == EF_BAD)) {
-		/* Figure out where to put the unit */
-		/* First, figure out the distance from the two */
-		rx = diffx((int)land.lnd_x, x);
-		ry = diffy((int)land.lnd_y, y);
-		/* Next, determine which direction to add it to the center */
-		/* We can only do this if imaging and we have gotten the center
-		   up above by imaging the sectors. */
-		rx = deltax(x, ns.range.lx) + rx;
-		ry = deltay(y, ns.range.ly) + ry;
+		rx = deltx(&ns.range, land.lnd_x);
+		ry = delty(&ns.range, land.lnd_y);
 		/* &~0x20 makes it a cap letter */
 		rad[ry][rx] = (*lchr[(int)land.lnd_type].l_name) & ~0x20;
 	    }