diff --git a/src/Prep/DemRaw2ascii/rawdem.h b/src/Prep/DemRaw2ascii/rawdem.h
index 24578d64..ca8a20cc 100644
--- a/src/Prep/DemRaw2ascii/rawdem.h
+++ b/src/Prep/DemRaw2ascii/rawdem.h
@@ -32,7 +32,7 @@
 
 typedef struct {
     /* header info */
-    int big_endian;  /* true if big, false if little */
+    int big_endian;  /* true if data source is big, false if little */
     int nrows;       /* number of rows */
     int ncols;       /* number of cols */
     int ulxmap;      /* X coord of center of upper left pixel in arcsec */