Path: ...!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: VanguardLH Newsgroups: comp.mobile.android Subject: Re: precision coordinates Date: Sun, 23 Jun 2024 19:18:25 -0500 Organization: Usenet Elder Lines: 53 Sender: V@nguard.LH Message-ID: <1w52koo7kv9fz$.dlg@v.nguard.lh> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Trace: individual.net B/R3mQDGq6vlTL9LSJmGWAQMgCGaKmWWRSwBBvC6x6e3T/Ce0T Keywords: VanguardLH,VLH Cancel-Lock: sha1:xGEnD3Zi8XNpx3/zv7ZUglOt8vs= sha256:vfL5VFzY20LLje7LaE28/V+SJPRNK/MXnDQvsbUasgo= User-Agent: 40tude_Dialog/2.0.15.41 Bytes: 3394 Andy Burns wrote: > bad sector wrote: > >> How would I map with precision about 900 planted trees on >> google-earth-pro? As a manual method I would think of taking a hundred >> readings on each with my phone and averaging them out, but that is a LOT >> of work (did it once with a bubble-sextant to win a bet). Is there an >> fdroid app to do this sort of thing (not interested in signupware)? Any >> other ideas? > > Surveying like that probably requires either differential GPS or > real-time kinematics GPS. DGPS stations don't provide 100% coverage of the USA. See: https://gssc.esa.int/navipedia/index.php/Differential_GPS The light blue is single station coverage. Dark blue is overlapping coverage. There are still some uncovered areas. Coverage also requires line-of-site, so if you're in a tree dense valley you might not be able to get the DPGS signal. DPGS stations are land based. GPS III satellites eliminate the need for DPGS. They are 3 times more accurate. Instead of an average accuracy of 5 to 10 meters, they have a range of 1 to 3 meters. I don't know if smart phone makers can access the GPS III satellites, though. Might be accessible only by gov't or military agencies, so you'd have to resort to the land-based DGPS stations if reachable. https://www.lockheedmartin.com/en-us/products/gps.html As for the OP's request to add coordinates to [online] maps, well, how old are the maps? A pic of an area could be 3 years old, so what others would see with the given coordinates could be before the trees were planted, or when they were still seedlings and not visible on the map. I've seen aerial maps that were lacking the buildings that I knew were there. With Google Earth, you can zoom in to see the capture date in the status bar, or use the "Historical Imagery" feature to see the date stamp. The GE pic of my house is dated 5/23/2023, or just over a year ago. Still shows the massive oak in the backyard that was cut down a month ago, and the zoomed-in image looks like a blocky cartoon. No way it'll show seedlings or saplings. Insufficient detail. I can see the handicap ramp at the front of the house, but no one else would know what that elongated blob represented. I haven't played with Google Maps/Earth to know if you can request access to higher detailed satellite images to see something like saplings, or make out the brand and model of car on the street. It's not like what you see in the movies where a spy satellite focuses down to a pack of cigarettes.