Mileage Math
Aug 10, 2019 | 12:30 pm
#16
Join Date: Jan 2005
Location: Washington, DC
Programs: DL DM/MM, and major hotels
Posts: 503
Miles Flown
On the topic of mileage math, I noticed today that the miles flown reported on the Delta app is not symmetric. For example DCA-MSP gets 906 miles, but the reverse is 931. SFO-MSP is 1589, but the reverse is 1574. When I've actually collected the miles, I've never noticed such asymmetry.
Aug 10, 2019 | 1:24 pm
#17
A FlyerTalk Posting Legend
Join Date: Sep 2009
Location: Minneapolis: DL DM charter 2.3MM
Programs: A3*Gold, SPG Plat, HyattDiamond, MarriottPP, LHW exAccess, ICI, Raffles Amb, NW PE MM, TWA Gold MM
Posts: 102,617
If I look at my itineraries, MSP-CDG is 4206 miles while CDG-MSP is 4207. The actual number that DL used when posting to my account was 4222.
However, my favorite example (so far) is MSP-HND at 5932 miles but HND-MSP is 5950. Actual was 5982.
On an itinerary, ATL-EZE is 5015 while EZE-ATL is 4999, so the hypothesis that DL thinks the trip back home is longer doesn't work. Last year DL thought it was 4999 each way.
However, my favorite example (so far) is MSP-HND at 5932 miles but HND-MSP is 5950. Actual was 5982.
On an itinerary, ATL-EZE is 5015 while EZE-ATL is 4999, so the hypothesis that DL thinks the trip back home is longer doesn't work. Last year DL thought it was 4999 each way.
Last edited by MSPeconomist; Aug 10, 2019 at 1:34 pm
Aug 13, 2019 | 6:48 pm
#19
Join Date: Aug 2019
Posts: 25
The miles that are credited to accounts are all GPS based using fairly accurate data and likely not assuming that Earth is perfectly spherical.
I say that because it is the methodology written up by gcmap where I've found matching MQM accuracy down to the mile.
The discrepancy of Delta's itinerary comes from using a different database of distances for airport pairs. Probably two different people coded up the itinerary and the skymiles accounting and they couldn't be bothered to match.
I say that because it is the methodology written up by gcmap where I've found matching MQM accuracy down to the mile.
The discrepancy of Delta's itinerary comes from using a different database of distances for airport pairs. Probably two different people coded up the itinerary and the skymiles accounting and they couldn't be bothered to match.
Aug 14, 2019 | 12:43 am
#20
Join Date: May 2006
Location: GA
Programs: VA-SLV, QF-GLD, DL-PM, UA-ex1K, AA-exPLT, HH-DM, IHG-PLT, MR-GLD
Posts: 8,353
The miles that are credited to accounts are all GPS based using fairly accurate data and likely not assuming that Earth is perfectly spherical.
I say that because it is the methodology written up by gcmap where I've found matching MQM accuracy down to the mile.
The discrepancy of Delta's itinerary comes from using a different database of distances for airport pairs. Probably two different people coded up the itinerary and the skymiles accounting and they couldn't be bothered to match.
I say that because it is the methodology written up by gcmap where I've found matching MQM accuracy down to the mile.
The discrepancy of Delta's itinerary comes from using a different database of distances for airport pairs. Probably two different people coded up the itinerary and the skymiles accounting and they couldn't be bothered to match.
None of this has anything to do with GPS.
Last edited by CPMaverick; Aug 14, 2019 at 12:49 am