/
gps.py
270 lines (255 loc) · 10.1 KB
/
gps.py
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# -*- coding: utf-8 -*-
import sys
import struct
from fractions import Fraction
SOI = b"\xff\xd8"
APP1 = b"\xff\xe1"
EXIF = b"\x45\x78\x69\x66"
ENDIAN_INTEL = b"\x49\x49"
ENDIAN_MOTOROLA = b"\x4d\x4d"
TAG_GPS = b"\x88\x25"
TAG_LAT_REF = b"\x00\x01"
TAG_LAT = b"\x00\x02"
TAG_LON_REF = b"\x00\x03"
TAG_LON = b"\x00\x04"
TAG_ALT_REF = b"\x00\x05"
TAG_ALT = b"\x00\x06"
TYPE_UBYTE = b"\x00\x01"
TYPE_ASCII = b"\x00\x02"
TYPE_USHORT = b"\x00\x03"
TYPE_ULONG = b"\x00\x04"
TYPE_URATIONAL = b"\x00\x05"
TYPE_BYTE = b"\x00\x06"
TYPE_UNDEFINED = b"\x00\x07"
TYPE_SHORT = b"\x00\x08"
TYPE_LONG = b"\x00\x08"
TYPE_RATIONAL = b"\x00\x0A"
TYPE_FLOAT = b"\x00\x0B"
TYPE_DFLOAT = b"\x00\x0C"
dms_lat_deg = 'dms_lat_deg'
dms_lat_min = 'dms_lat_min'
dms_lat_sec = 'dms_lat_sec'
dms_lon_deg = 'dms_lon_deg'
dms_lon_min = 'dms_lon_min'
dms_lon_sec = 'dms_lon_sec'
dm_lat_deg = 'dm_lat_deg'
dm_lat_min = 'dm_lat_min'
dm_lon_deg = 'dm_lon_deg'
dm_lon_min = 'dm_lon_min'
dd_lat_deg = 'dd_lat_deg'
dd_lon_deg = 'dd_lon_deg'
lat_ref = 'lat_ref'
lon_ref = 'lon_ref'
unpack_endian = ''
CC = 0
class Gps_info():
def __init__(self,form,gps):
self._form = form
self._gps = gps
if form == "dd":
self._gps[dms_lat_deg] = int(gps[dd_lat_deg])
self._gps[dms_lat_min] = int((gps[dd_lat_deg] - self._gps[dms_lat_deg] )* 60)
self._gps[dms_lat_sec] = (gps[dd_lat_deg] - self._gps[dms_lat_deg] - self._gps[dms_lat_min]/60) * 3600
self._gps[dms_lon_deg] = int(gps[dd_lon_deg])
self._gps[dms_lon_min] = int((gps[dd_lon_deg] - self._gps[dms_lon_deg]) * 60)
self._gps[dms_lon_sec] = (gps[dd_lon_deg] - self._gps[dms_lon_deg] - self._gps[dms_lon_min]/60) * 3600
self._gps[dm_lat_deg] = int(gps[dd_lat_deg])
self._gps[dm_lat_min] = (gps[dd_lat_deg] - int(gps[dd_lat_deg]))*60
self._gps[dm_lon_deg] = int(gps[dd_lon_deg])
self._gps[dm_lon_min] = (gps[dd_lon_deg] - int(gps[dd_lon_deg]))*60
elif form == "dm":
self._gps[dms_lat_deg] = gps[dm_lat_deg]
self._gps[dms_lat_min] = int(gps[dm_lat_min])
self._gps[dms_lat_sec] = (gps[dm_lat_min] - int(gps[dm_lat_min]))*60
self._gps[dms_lon_deg] = gps[dm_lon_deg]
self._gps[dms_lon_min] = int(gps[dm_lon_min])
self._gps[dms_lon_sec] = (gps[dm_lon_min] - int(gps[dm_lon_min]))*60
self._gps[dd_lat_deg] = gps[dm_lat_deg] + gps[dm_lat_min]/60
self._gps[dd_lon_deg] = gps[dm_lon_deg] + gps[dm_lon_min]/60
elif form == "dms":
self._gps[dm_lat_deg] = gps[dms_lat_deg]
self._gps[dm_lat_min] = float(gps[dms_lat_min] + (gps[dms_lat_sec]/60))
self._gps[dm_lon_deg] = gps[dms_lon_deg]
self._gps[dm_lon_min] = float(gps[dms_lon_min] + (gps[dms_lon_sec]/60))
self._gps[dd_lat_deg] = float(gps[dms_lat_deg] + (gps[dms_lat_min]/60) + (gps[dms_lat_sec]/3600))
self._gps[dd_lon_deg] = float(gps[dms_lon_deg] + (gps[dms_lon_min]/60) + (gps[dms_lon_sec]/3600))
else:
print("wrong format input!\n")
return
def __repr__(self):
return "GPS INFO\nDMS_LAT : {0}°{1}'{2}\", DMS_LON : {3}°{4}'{5}\"\nDD_LAT : {6}, DD_LON : {7}".format(self._gps[dms_lat_deg], self._gps[dms_lat_min], self._gps[dms_lat_sec], self._gps[dms_lon_deg], self._gps[dms_lon_min], self._gps[dms_lon_sec], self._gps[dd_lat_deg], self._gps[dd_lon_deg])
def __getitem__(self,key):
if key not in self._gps:
print("Given key not found. Check GPS format.\n")
return
return self._gps[key]
def __setitem__(self,key,val):
self._gps[key] = val
def struct_unpack(data):
global unpack_endian
if len(data) == 1:
return struct.unpack(unpack_endian + 'B',data)[0]
elif len(data) == 2:
return struct.unpack(unpack_endian + 'H',data)[0]
elif len(data) == 4:
return struct.unpack(unpack_endian + 'L',data)[0]
elif len(data) == 8:
return struct.unpack(unpack_endian + 'Q',data)[0]
def check_input(data):
if data[0:2] != SOI or data[2:4] != APP1:
return False
if data[6:10] != EXIF:
return False
return True
def interpret_gps(data):
pos_info = dict()
gps_tag = data.find(TAG_GPS)
global unpack_endian
if data[12:14] == ENDIAN_INTEL:
unpack_endian = '<'
elif data[12:14] == ENDIAN_MOTOROLA:
unpack_endian = '>'
else:
print("Unknown byte order of file!\n")
return
#print("%d\n"%len(data[gps_tag + 8: gps_tag + 12]))
gps_index = struct_unpack(data[gps_tag + 8: gps_tag + 12])
gps_index += 0xc
#print("GPS index : %x\n" % gps_index)
gps_len = struct_unpack(data[gps_index:gps_index+2])
#print("gps components num : %d"%gps_len)
gps_dict = dict()
pos = gps_index+2
for i in range(gps_len):
if data[pos:pos+2] == TAG_LAT_REF:
if data[pos+2:pos+4] != TYPE_ASCII:
print("Lat_ref type not 0x02(ascii)!\n")
return
if data[pos+8:pos+9] != b"\x4e" and data[pos+8:pos+9] != b"\x53":
print("Lat_ref not \"N\" nor \"S\"!\n")
return
if data[pos+8] == b"\x4e":
gps_dict[lat_ref] = 'N'
elif data[pos+8:pos+9] == b"\x53":
gps_dict[lat_ref] = 'S'
pos_info[lat_ref] = pos+8
elif data[pos:pos+2] == TAG_LAT:
if data[pos+2:pos+4] != TYPE_URATIONAL:
print("Lat type not 0x05(urational)!\n")
return
if struct_unpack(data[pos+4:pos+8]) != 3:
print("Lat components number is not 3!(%x)\n" % struct_unpack(data[pos+4:pos+8]))
return
lat_pos = struct_unpack(data[pos+8:pos+12])
lat_pos += 0xc
# store pos info
pos_info[dms_lat_deg] = lat_pos
gps_dict[dms_lat_deg] = float(struct_unpack(data[lat_pos:lat_pos+4])/ struct_unpack(data[lat_pos+4:lat_pos+8]))
gps_dict[dms_lat_min] = float(struct_unpack(data[lat_pos+8:lat_pos+12])/ struct_unpack(data[lat_pos+12:lat_pos+16]))
gps_dict[dms_lat_sec] = float(struct_unpack(data[lat_pos+16:lat_pos+20])/ struct_unpack(data[lat_pos+20:lat_pos+24]))
if CC:
print(struct_unpack(data[lat_pos:lat_pos+4]))
print(struct_unpack(data[lat_pos+4:lat_pos+8]))
print(struct_unpack(data[lat_pos+8:lat_pos+12]))
print(struct_unpack(data[lat_pos+12:lat_pos+16]))
print(struct_unpack(data[lat_pos+16:lat_pos+20]))
print(struct_unpack(data[lat_pos+20:lat_pos+24]))
elif data[pos:pos+2] == TAG_LON_REF:
if data[pos+2:pos+4] != TYPE_ASCII:
print("Lon_ref type not 0x02(ascii)!(%s at %x)\n" % (data[pos+2:pos+4].hex(), pos))
return
if data[pos+8:pos+9] != b"\x45" and data[pos+8:pos+9] != b"\x57":
print("Lon_ref not \"E\" nor \"W\"!\n")
return
if data[pos+8:pos+9] == b"\x45":
gps_dict[lat_ref] = 'E'
elif data[pos+8:pos+9] == b"\x57":
gps_dict[lat_ref] = 'W'
pos_info[lon_ref] = pos+8
elif data[pos:pos+2] == TAG_LON:
if data[pos+2:pos+4] != TYPE_URATIONAL:
print("Lon type not 0x05(urational)!\n")
return
if struct_unpack(data[pos+4:pos+8]) != 3:
print("Lon components number is not 3!(%x)\n" % struct_unpack(data[pos+4:pos+8]))
return
lon_pos = struct_unpack(data[pos+8:pos+12])
lon_pos += 0xc
# store pos info
pos_info[dms_lon_deg] = lon_pos
gps_dict[dms_lon_deg] = float(struct_unpack(data[lon_pos:lon_pos+4])/ struct_unpack(data[lon_pos+4:lon_pos+8]))
gps_dict[dms_lon_min] = float(struct_unpack(data[lon_pos+8:lon_pos+12])/ struct_unpack(data[lon_pos+12:lon_pos+16]))
gps_dict[dms_lon_sec] = float(struct_unpack(data[lon_pos+16:lon_pos+20])/ struct_unpack(data[lon_pos+20:lon_pos+24]))
if CC:
print(struct_unpack(data[lon_pos:lon_pos+4]))
print(struct_unpack(data[lon_pos+4:lon_pos+8]))
print(struct_unpack(data[lon_pos+8:lon_pos+12]))
print(struct_unpack(data[lon_pos+12:lon_pos+16]))
print(struct_unpack(data[lon_pos+16:lon_pos+20]))
print(struct_unpack(data[lon_pos+20:lon_pos+24]))
pos += 12
try:
ret_gps_info = Gps_info("dms", gps_dict)
except:
print("Error in making new Gps_info instance with interpreted data!\n")
return
print(ret_gps_info)
return ret_gps_info, pos_info
def rebuild_gps(data,new_gps,pos_info):
new_data = bytearray(len(data))
new_data[:] = data
print(new_gps)
pos_lat_ref = pos_info[lat_ref]
pos_lon_ref = pos_info[lon_ref]
pos_lat_deg = pos_info[dms_lat_deg]
pos_lon_deg = pos_info[dms_lon_deg]
#print(new_data[pos_lat_ref])
#print(new_gps[lat_ref])
new_data[pos_lat_ref] = ord(new_gps[lat_ref])
new_data[pos_lon_ref] = ord(new_gps[lon_ref])
new_data[pos_lat_deg:pos_lat_deg+4] = struct.pack('>L',Fraction(new_gps[dms_lat_deg]).numerator)
new_data[pos_lat_deg+4:pos_lat_deg+8] = struct.pack('>L',Fraction(new_gps[dms_lat_deg]).denominator)
new_data[pos_lat_deg+8:pos_lat_deg+12] = struct.pack('>L',Fraction(new_gps[dms_lat_min]).numerator)
new_data[pos_lat_deg+12:pos_lat_deg+16] = struct.pack('>L',Fraction(new_gps[dms_lat_min]).denominator)
#print(Fraction(new_gps[dms_lat_sec]).numerator)
new_data[pos_lat_deg+16:pos_lat_deg+20] = struct.pack('>L',Fraction(new_gps[dms_lat_sec]).limit_denominator(1000).numerator)
new_data[pos_lat_deg+20:pos_lat_deg+24] = struct.pack('>L',Fraction(new_gps[dms_lat_sec]).limit_denominator(1000).denominator)
# now longitude
new_data[pos_lon_deg:pos_lon_deg+4] = struct.pack('>L',Fraction(new_gps[dms_lon_deg]).numerator)
new_data[pos_lon_deg+4:pos_lon_deg+8] = struct.pack('>L',Fraction(new_gps[dms_lon_deg]).denominator)
new_data[pos_lon_deg+8:pos_lon_deg+12] = struct.pack('>L',Fraction(new_gps[dms_lon_min]).numerator)
new_data[pos_lon_deg+12:pos_lon_deg+16] = struct.pack('>L',Fraction(new_gps[dms_lon_min]).denominator)
new_data[pos_lon_deg+16:pos_lon_deg+20] = struct.pack('>L',Fraction(new_gps[dms_lon_sec]).limit_denominator(1000).numerator)
new_data[pos_lon_deg+20:pos_lon_deg+24] = struct.pack('>L',Fraction(new_gps[dms_lon_sec]).limit_denominator(1000).denominator)
if CC:
print(Fraction(new_gps[dms_lat_deg]))
print(Fraction(new_gps[dms_lat_min]))
print(Fraction(new_gps[dms_lat_sec]))
print(Fraction(new_gps[dms_lon_deg]))
print(Fraction(new_gps[dms_lon_min]))
print(Fraction(new_gps[dms_lon_sec]))
return new_data
def main():
try:
f = open(sys.argv[1],"rb")
except:
print("Error opening input file!\n")
return -1
data = f.read()
if check_input(data) is False:
print("File format error!\n")
return
gps, pos_info = interpret_gps(data)
if gps is None:
print("GPS info not found!\n")
new_gps = Gps_info("dd",{dd_lat_deg:35.255153,dd_lon_deg:129.085912,lat_ref:'N',lon_ref:'E'})
new_data = rebuild_gps(data,new_gps,pos_info)
try:
g = open("gps_" + sys.argv[1], "wb")
g.write(new_data)
except:
print("Error writing to file!\n")
return -1
g.close()
f.close()
main()