Попробуйте это:
def getArraysofArray(my_data):
FinalList=[]
temp=[]
for i in range(len(my_data)):
if(i==0):
temp.append(my_data[i])
continue
if(my_data[i][0]!=my_data[i-1][0]):
FinalList.append(temp)
temp=[]
if(my_data[i]==my_data[-1]):
FinalList.append(temp)
temp.append(my_data[i])
return FinalList
# Main / Testing of Function
my_data=[[500,39.984608 ,116.317761]
,[500,39.984563,116.317517]
,[500,39.984539,116.317294]
,[605,26.16167,119.943128]
,[605,26.161566,119.942352]
,[605,26.161558,119.942401]
,[745,22.814336,108.332281]
,[745,22.81429,108.3322566]
,[745,22.81432,108.3322583]]
list=getArraysofArray(my_data)
print(list)
# Output
[[[500, 39.984608, 116.317761], [500, 39.984563, 116.317517], [500, 39.984539, 116.317294]],
[[605, 26.16167, 119.943128], [605, 26.161566, 119.942352], [605, 26.161558, 119.942401]],
[[745, 22.814336, 108.332281], [745, 22.81429, 108.3322566], [745, 22.81432, 108.3322583]]]