Re: precision coordinates

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.