diff --git a/pylot/core/active/surveyUtils.py b/pylot/core/active/surveyUtils.py
index 64d81a05..0c766166 100644
--- a/pylot/core/active/surveyUtils.py
+++ b/pylot/core/active/surveyUtils.py
@@ -192,116 +192,3 @@ def findTracesInRanges(shot_dict, distancebin, pickbin):
                     shots_found[shot.getShotnumber()].append(traceID)
 
     return shots_found
-        
-def vgrids2VTK(inputfile = 'vgrids.in', outputfile = 'vgrids.vtk'):
-    def getDistance(angle):
-        PI = np.pi
-        R = 6371.
-        distance = angle / 180 * (PI * R)
-        return distance
-
-    def readNumberOfPoints(filename):
-        fin = open(filename, 'r')
-        vglines = fin.readlines()
-
-        nR = int(vglines[1].split()[0])
-        nTheta = int(vglines[1].split()[1])
-        nPhi = int(vglines[1].split()[2])
-
-        fin.close()
-        return nR, nTheta, nPhi
-
-    def readDelta(filename):
-        fin = open(filename, 'r')
-        vglines = fin.readlines()
-
-        dR = float(vglines[2].split()[0])
-        dTheta = float(vglines[2].split()[1])
-        dPhi = float(vglines[2].split()[2])
-
-        fin.close()
-        return dR, dTheta, dPhi
-
-    def readStartpoints(filename):
-        fin = open(filename, 'r')
-        vglines = fin.readlines()
-
-        sR = float(vglines[3].split()[0])
-        sTheta = float(vglines[3].split()[1])
-        sPhi = float(vglines[3].split()[2])
-
-        fin.close()
-        return sR, sTheta, sPhi
-
-    def readVelocity(filename):
-        vel = []; count = 0
-        fin = open(filename, 'r')
-        vglines = fin.readlines()
-
-        for line in vglines:
-            count += 1
-            if count > 4:
-                vel.append(float(line.split()[0]))
-
-        print("Read %d points out of file: %s" %(count - 4, filename))
-        return vel
-
-    R = 6371 # earth radius
-    outfile = open(outputfile, 'w')
-
-    # Theta, Phi in radians, R in km
-    nR, nTheta, nPhi = readNumberOfPoints(inputfile)
-    dR, dTheta, dPhi = readDelta(inputfile)
-    sR, sTheta, sPhi = readStartpoints(inputfile)
-    vel = readVelocity(inputfile)
-
-    nX = nPhi; nY = nTheta; nZ = nR
-
-    sZ = sR - R
-    sX = getDistance(np.rad2deg(sPhi))
-    sY = getDistance(np.rad2deg(sTheta))
-
-    dX = getDistance(np.rad2deg(dPhi))
-    dY = getDistance(np.rad2deg(dTheta))
-    
-    xGrid = np.linspace(sX, sX + (dX * nX), nX)
-    yGrid = np.linspace(sZ, sZ + (nY * dY), nY)
-    zGrid = np.linspace(sZ, sZ + (nR * dR), nR)
-    nPoints = len(xGrid) * len(yGrid) * len(zGrid)
-
-    # write header
-    print("Writing header for VTK file...")
-    outfile.writelines('# vtk DataFile Version 3.1\n')
-    outfile.writelines('Velocity on FMTOMO vgrids.in points\n')
-    outfile.writelines('ASCII\n')
-    outfile.writelines('DATASET POLYDATA\n')
-    outfile.writelines('POINTS %15d float\n' %(nPoints))
-
-    # write coordinates
-    print("Writing coordinates to VTK file...")
-    for z in zGrid:
-        for y in yGrid:
-            for x in xGrid:
-                outfile.writelines('%10f %10f %10f \n' %(x, y, z))
-
-
-    outfile.writelines('VERTICES %15d %15d\n' %(nPoints, 2 * nPoints))
-
-    # write indices
-    print("Writing indices to VTK file...")
-    for index in range(nPoints):
-        outfile.writelines('%10d %10d\n' %(1, index))
-
-    outfile.writelines('POINT_DATA %15d\n' %(nPoints))
-    outfile.writelines('SCALARS velocity float %d\n' %(1))
-    outfile.writelines('LOOKUP_TABLE default\n')
-
-    # write velocity
-    print("Writing velocity values to VTK file...")
-    for velocity in vel:
-        outfile.writelines('%10f\n' %velocity)
-
-    outfile.close()
-    print("Wrote velocity grid for %d points to file: %s" %(nPoints, outputfile))
-    return
-