Re: app for precision coordinates

bad sector <forgetski@_INVALID.net> wrote:

On 6/23/24 16:34, VanguardLH wrote:

bad sector <forgetski@_INVALID.net> wrote:
 

On 6/23/24 10:18, knuttle wrote:

On 06/23/2024 9:39 AM, 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?
>

I don't know about the  android version, but on the PC version you can
add pins to identify a specific location.
>
On the PC version of Google Earth Pro, you can determine the longitude
and latitude to six decimal places or get good numbers for location
about 300 feet apart.  This 300 feet was calculated by zooming Google
Earth to its maximum and reading the coordinates of each location.

>
About 1/3 of the trees are now just big enough to show on GE but the
rest are not visible yet. It is to place THESE that I need the
lat-longs. And I'm looking for about one foot of precision :-) which is
not easy with the imagery resolution provided out here in the sticks. If
I were living in the densely populated areas a six inch seedling would
show but all I get is about a 1.5-2.0 foot circle to show.
>
During a drinking marathon I once bet with the owner of a hotel I was
staying at that I could measure the width of his hotel with a
bubble-sextant to within a foot. So I took like a hundred readings on
two corners, plotted them and marked the center of each 'blob'. Won the
$200 bet which today would be like $2000. If I were a codepuncher I'd
try to write an app that plots for maybe 30 minutes and then coughs up
the centerpoint of the same sort of blob as the position.
>
I'll be planting another hundred or so in the next three months so I'd
like to refine my mapping. 220 of the trees are yellow-cedars not native
here and many fans are watching to see how they will survive. I want to
map them on GE and update the pictures from time to time.

 
I would think GPS would work to record the locations of the trees.
While different GPS receivers have varying levels of accuracy, even your
phone's GPS radio should suffice.  After all, the trees have to be
planted far enough apart to account for their canopies.
 
https://crec.ifas.ufl.edu/media/crecifasufledu/extension/plant-pathology-/greening/pdf/GPSAccuracyforTreeScouting.pdf
https://fruitgrowersnews.com/article/precise-gps-systems-increase-planting-efficiency/
 
Since you are at site when planting the trees, use GPS to record where
you planted.  Then use the GPS coordinates, or convert to long-lat, to
position in a map.
 
GPS radios in smart phones are accurate to within 3 to 5 meters (1o to
16 feet).  Don't know far apart you are planting the seedling to account
for their canopy sizes later in life.  If a smart phone's GPS isn't
accurate enough, you can buy GPS receivers that are more accurate.
 
I figure if a hand-held GPS navigator is good for recording trails that
it is probably sufficient to record tree locations.

 
thanks for the time to respond
 
I once bought a garmin gps camera attachment for my slr camera but it
too was wishy washy; never even tried composing blobs with it. With 900
trees (and growing) the only 'involvement' I have time for is putting
the smart-phone down and leaving it there to collect its wanderings over
maybe fifteen minutes or less. The trees are at different distances but
what I want is 1-foot accuracy not so much because it's indispensible
but because I'm a sucker for at least a semblance of reality.
Google-Earth placemarks is one tool I use giving the trees icons
representing the tree species. Ideally I'd like to attach an actual
photo of the tree to appear in a popup on click or something along those
lines and all of it uploaded instead of locally stored.
 
Not sure if math averaging would give the same result as hitting the
center of plotted coordinates but with the processing utility in a phone
an APP could ideally produce the ultimately VERY accurate result ...just
like I once did with a bubble sextant meant to produce plots in terms of
miles at the center of triangles of probabilty. That stunt took half an
hour per reading and I did maybe fifty on each of two corners, I forget
the actual number, it was a royal pissing contest :-)

I think averaging would only work well if you managed to get the GPS
device connected to different GPS satellites within reach.  Then repeat
by using another different set of 3 GPS satellites.  I would think
reusing the same 3 GPS satellites to get multiple readings from them
would result in the same offset (inaccuracy) in each reading.  However,
maybe walking around in a circle around the focus point to take multiple
readings might work to average the multiple readings from the same set
of 3 satellites.

Someone here mentioned DGPS (differential GPS) which uses ground-based
positioning stations.  Those have a 200-mile range if there are no
blocks to the signal (mountains, trees, buildings).  Never got around to
using those, so no experience with them.  Don't remember seeing a smart
phone stating it can use DGPS, so you'll likely have to find a GPS
receiver that can find DGPS stations.