diff -r cf4c3eefdead -r a369c6597982 src/backend/APT/APTFileIO.cpp
--- src/backend/APT/APTFileIO.cpp	Sun Feb 05 14:33:21 2017 +0000
+++ src/backend/APT/APTFileIO.cpp	Sun Feb 05 18:27:46 2017 +0000
@@ -24,7 +24,6 @@
 #include "../../common/translation.h"
 
 
-
 #include <cstring>
 #include <new>
 
@@ -1123,7 +1122,7 @@
 	return 0;
 }
 
-//Load a TAPSIM Binfile
+//Load a TAPSIM Binfile, which is the input geometry format for TAPSIM
 unsigned int loadTapsimBinFile(const char *fileName, unsigned int &progress, ATOMIC_BOOL &wantAbort, vector<IonHit> &posIons)
 {
 	ifstream f(fileName,std::ios::binary); 
@@ -1136,7 +1135,7 @@
 	fileSize = f.tellg();
 	f.seekg(0,std::ios::beg);
 
-	//TAPSIM's binary geometery input format is not totally clearly documented
+	//TAPSIM's binary geometry input format is not totally clearly documented
 	// but an example is provided. So best efforts are us.
 
 	std::string str;
@@ -1202,7 +1201,7 @@
 			return TAPSIM_ERR_FILE_FORMAT_FAIL;
 		}
 
-		//Contrary to docuemntation, ids appear to be "short", not "unsigned int"	
+		//Contrary to documentation, ids appear to be "short", not "unsigned int"	
 		size_t recordSize=( (numbersPresent ? 1:0 )*sizeof(unsigned int) + 
 			3*sizeof(float) + (idsPresent ?1:0)*sizeof(short));
 
@@ -1222,11 +1221,24 @@
 			//Transfer position data
 #ifdef __LITTLE_ENDIAN__
 			h.setPos(Point3D((float*)(buffer)));
-#elif __BIG_ENDIAN__
-			static_assert(false); //TODO: IMPLEMENT ME
-#endif
+
 			//assign the ID as the mass to charge
 			h.setMassToCharge(*( (short*)(buffer+12) ));
+#elif __BIG_ENDIAN__
+			{
+			Point3D pt((float*)(buffer));
+			pt.switchEndian();
+			h.setPos(pt);
+
+			uint16_t s;
+			s =*( (uint16_t*)(buffer+12) );
+			shortSwapBytes(s);
+
+			
+
+			}
+			
+#endif
 		
 			posIons[ui]=h;
 
@@ -1291,7 +1303,7 @@
 
 	if(!flip)
 	{
-		//Fkip the endinanness
+		//Flip the endinanness
 		for(size_t ui=0;ui<4;ui++)
 			floatSwapBytes(buffer+ui);
 	}
@@ -1300,7 +1312,7 @@
 	outF.write((char*)&intData,4);
 
 	intData=3;
-	//Write out verion num  as "3"
+	//Write out version num  as "3"
 	outF.write((char*)&intData,4);
 
 	for(size_t ui=0;ui<nPoints;ui++)
@@ -1339,7 +1351,7 @@
 	TEST((ions[0].getPos().sqrDist(Point3D(1,1,0)) < sqrtf(std::numeric_limits<float>::epsilon())),"Checking read/write OK");
 	//Load using auto-detection of endinanness
 
-	//Load, forcing assuming cont4ents are little endianness as requried
+	//Load, forcing assuming contents are little endianness as required
 	TEST(!LoadATOFile(filename.c_str(),ions,dummyProgress,wantAbort,1),"ATO load test (forced endianness)");
 	TEST(ions.size() == 100,"ion size check");
 	TEST((ions[0].getPos().sqrDist(Point3D(1,1,0)) < sqrtf(std::numeric_limits<float>::epsilon())),"checking read/write OK");
diff -r cf4c3eefdead -r a369c6597982 src/common/endianTest.h
--- src/common/endianTest.h	Sun Feb 05 14:33:21 2017 +0000
+++ src/common/endianTest.h	Sun Feb 05 18:27:46 2017 +0000
@@ -51,7 +51,7 @@
 
 inline int is_littleendian() { return (*(char*)&ENDIAN_TEST) == 1 ;}
 
-
+//this may fail on some compilers??
 inline void floatSwapBytes(float *inFloat)
 {
 	//Use a union to avoid strict-aliasing error
@@ -69,5 +69,19 @@
 
 	*inFloat=fb.f;
 }
+inline void shortSwapBytes(short *inShort)
+{
+	//Use a union to avoid strict-aliasing error
+	union ShortSwapUnion{
+	   short s;
+	   char c[2];
+	} ;
+	ShortSwapUnion sa,sb;
+	sa.s = *inShort;
 
+	sb.c[0] = sa.c[1];
+	sb.c[1] = sa.c[0];
+
+	*inShort=sb.s;
+}
 #endif