Hi Walter, Altimeter+By Sichtwerk GmbH, Appenzell <http://itunes.apple.com/au/app/altimeter/id417204570?mt=8>
Cheers, Ronni 17" MacBook Pro 2.3GHz Quad-Core i7 “Thunderbolt" 2.3GHz / 8GB / 750GB @ 7200rpm HD OS X 10.6.7 Snow Leopard Windows 7 Ultimate (under sufferance) On 11/06/2011, at 3:12 PM, F.W. Hänel wrote: > > Hi Ray, > > Looked for it in the app store. Can only find others, are you sure its > available > in the AUS store ? > > Cheers, > > Walter > On 11/06/2011, at 2:21 , Ray Forma wrote: > >> >> There are several altimeter apps for the iPhone. >> >> The one I would choose would be the Sichtwerk one: >> >> <http://www.sichtwerk.com/referenzen/altimeter/> (this site is in German) >> >> This simple app gives you your latitude and longitude in DMS (degrees, >> minutes, and seconds), as well as your altitude in m (or feet for the >> oldies). >> >> You are therefore not dependant on electronic maps, which will only download >> if you are within phone range. Take along a good, old-fashioned, paper map >> and find where you are from the app's coördinates. Useful in Australia where >> about 90% of the country is out of phone range. >> >> Nearly all of the various altimeter apps get their altimetric data from gps >> readings. The app measures how long it takes a gps signal to travel from the >> satellite to your iPhone. The satellite signal includes the satellite's >> altitude, as well as its position. Assuming a standard signal speed, the >> iphone can therefore calculate the distance between the satellite and the >> phone. Using the distance and positional data from several satellites allows >> your iPhone to calculate your absolute altitude, as well as your latitude >> and longitude. >> >> This is great, but there is a problem. The temperature and density of the >> air along the satellite signal's path affects the speed of that signal. This >> introduces distance-from-satellite variations that your iPhone has no way of >> correcting. Assuming the distance variations are uniform, your latitude and >> longitude calculation will not be much affected, but there can be ±15m >> variations in altitude on normal days, and greater in very high-pressure or >> low-pressure locations, and very cold or hot locations. >> >> As with dedicated gps receiver altitude readings, take a reading at a known >> altitude as often as possible, work out the variation, and then apply the >> variation to your subsequent readings. >> >> In my experience you should take known readings about every 3 hours to make >> fairly reliable altitude reading corrections. >> >> The Sichtwerk app can apparently also use data from the ASTER satellite to >> improve its altimeter accuracy, but I'm not sure if it uses the ASTER >> temperature data in conjunction with the gps data to calculate altitude. If >> it works only from the ASTER satellite then it would not be usable most of >> the time because there is only 1 ASTER satellite. I don't think ASTER data >> are in public domain, so the app probably gets the aster data by data link; >> meaning that you have to be in phone range. >> >> I use my Swiss Army knife that has a built-in barometric altimeter if I want >> more precise altimeter data, again calibrating the knife every 3 hours. My >> knife gives me repeatable ±2m accuracy on any day that is not too stormy. I >> have never seen my version of the knife in Australian shops. I got mine in >> Switzerland. >> >> On 11/06/2011, at 10:54 AM, Stuart Breden wrote: >> >>> I see that Altimeter is reviewed in the latest Macworld magazine for June. >>> >>> It was also reviewed the Macworld site in April. A more detailed review >>> and did not appear to be very accurate. >>> >>> Is Altimeter the only application that measures altitude? Are others ore >>> accurate? >>> >>> Stuart Breden >>> PO Box 132 >>> Kalamunda WA 6926 >>> Ph: (08) 9257 1577 >>> Mbl: 0417 053 266 >>> >>> http://www.studiosixdigital.com/altimeter.html >>> http://www.macworld.com.au/app-guide/altimeter-28876/ >> -- The WA Macintosh User Group Mailing List -- Archives - <http://www.wamug.org.au/mailinglist/archives.shtml> Guidelines - <http://www.wamug.org.au/mailinglist/guidelines.shtml> Unsubscribe - <mailto:[email protected]>
