True south



  • russruss Solar Expert Posts: 593 ✭✭
    Re: True south

    Actually the offset was never a problem - all you needed was a GPS on the ground at a known location nearby and then make corrections.

    We did this routinely in port work in Eastern India years back.

    That was somewhat of a 'fools lock'.
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: True south
    niel wrote: »
    there's plenty of military receivers, but they are at a premium cost due not just to specs, but due to abuses seen while pressed into combat service. most commercial radios wouldn't last long under the same circumstances, but i can see the government or even the military itself stooping to cutting corners by going this route of commercial stuff.
    Back in the early days of GPS I saw a program (NOVA, maybe?) describing the tech and talking about the intentional inaccuracy in the civilian gear. It said that what the gov't was concerned about (among other things) was the possibility of Cessna cruise missiles using GPS for navigation. After 9/11 when it became obvious that there were folks perfectly willing to pilot a plane to their own oblivion, that particular concern became moot, I guess.
  • bmetbmet Solar Expert Posts: 630 ✭✭
    Re: True south
    kadesmith wrote: »
    Google earth is probably more accurate than your offroading GPS even if the aerial photo is a 2 meter aerial. You're GPS is typically accurate to within 15 meters. I don't know where you got the idea that they put an intentional % of error in Google. It's kind of hard to put an intentional error in an aerial photo. However, there is an intentional % of error in your off-road GPS that the gov't puts in satellites and varies from time to time so that recreational GPS units cannot be used for much more than that, recreation.

    I know Google Earth has error, because my commercial survey maps show 400 feet of disparity between its data and 'Google''s indication of the same landmarks.

    I can find the similar error in city searches, tho not as great. Whether the resolution is intentionally reduced for rural areas, or by zip code, big cities get much more detail than country roads.
  • Ralph DayRalph Day Solar Expert Posts: 975 ✭✭✭✭
    Re: True south

    It depends on whether there are aerial pictures to view (photo taken from aircraft) or only satellite pictures. The resolution of aerial shots are of course, superior. Some rural areas have aerial shots, but not any I want to look at.
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