Android Phone GPS for farming????

[California]

It seems like there are aps for everything.

It would be nice to optimize my route for watering 125 new trees in random locations among the thousand+ in the orchard. Presently, looking down or across the rows doesn't work that well because mature trees block view of the occasional new ones.

GPS- based mapping and real time route directions would help optimize my route and most important, assure that I didn't miss watering a new tree.

Are there libraries of Android GPS applications for farming? Is anyone using this? Is the GPS precision sufficient to take me to the general area of a previously-defined tree? The orchard grid is 20 ft x 20 ft and the new trees are usually visible among the mature ones when I get within 50~100 ft so I don't need surveyor-level precision - just an advisory to 'look over there', and a map showing all new trees/trees visited.

Thanks in advance for any comments!

 

[sailfast]

Yes. Just pick a GPS app and store each location as a waypoint.

 

[radioman]

the waypoint probably will work- but I dont think its accurate enough . Mine shows 15 ft off at times.

 

[s219]

We have an app on iOS that is used for this (Theodolite) but one limitation is that GPS in smart phones is only accurate to about 12-15 feet under optimal conditions. If you don't have a clear line of sight to the sky (such as under tree cover) the accuracy can drop quite a bit, and maybe only be 50-60 feet or worse.

 

[sailfast]

Mine is 5 feet.
For his purposes it doesn't matter if its even 20 or 30 off.

 

[s219]

5 feet accuracy isn't possible with the current GPS radios in smart phones (any app that reports 5 feet is likely computing the number or units wrong). The radios do 3 meter accuracy tops, just about 10 feet, but that only happens under the most optimal conditions.

Either way, if he only needs to be within 20-30 feet, it should be fine as long as there is a clear line of sight to the sky.

 

[California]

I have maybe 60% open sky while driving tree to tree. But if some satellites are near the horizon I would likely lose some while moving.

Here are a couple of pictures from last year. The first one shows how I need to drive close to a new tree before I see it - behind the little buck's antlers in this case. Kinda like an Easter Egg hunt.

The second picture shows why I want an efficient route. That little tractor struggles for traction pulling a full tank of water (2600 lbs, on 8" tires) uphill on disked ground. (I could pull with the larger tractor but this one maneuvers under the mature trees better).

Any suggestions on a specific GPS application for Android?

 

[MuleMn]

5 feet accuracy isn't possible with the current GPS radios in smart phones (any app that reports 5 feet is likely computing the number or units wrong). The radios do 3 meter accuracy tops, just about 10 feet, but that only happens under the most optimal conditions.

Either way, if he only needs to be within 20-30 feet, it should be fine as long as there is a clear line of sight to the sky.

Right on! You would have to go to WAAS ($2500) or RTK ($25,000+) to get more accuracy.

 

[California]

Can you improve accuracy by starting from a known survey monument?

 

[joshuabardwell]

Can you improve accuracy by starting from a known survey monument?

Not with a cell phone, no. Specialized surveyor's equipment, yes.

 

[wcampbell47]

I have been using a Delorme product in my van since 2002. Accuracy is within 3 meters - the length of the van. One of the handheld products may fit your need. Our community has an area wide garage sale every year. I drive around to the address of each sale and plug the co-ordinates into the Street Atlas. I then print a map from Street Atlas that has a waypoint for each sale location. Don't know if one of the hand held units could do something similar.

 

[MikeFarm]

Hi California

Get a Garmin GPS unit. From your photo it should have no probs finding satellites and it will gibe you an accuracy of about +- 15 feet to 20 ft. Maybe an eTrex 20 which is about US $200. But look into what models are available. I have an eTrex Vista HCx for bush walking. I get 5m accuracy from it even in very steep gulleys.

When you are at a new tree just add a waypoint. You can just click a button and add a location and even give it a number.

Then download QGIS from Welcome to the Quantum GIS Project which is an open source (and free) GIS application and you can read in the waypoints and create a map of them and keep you map up-to-date with new trees. Make a layer of "new trees" and maybe a separate layer of "diseased trees" or "trees to cut down" etc.

Mike

 

[California]

I like the idea of a Garmin handheld hiking GPS. Or maybe an automotive dashboard unit. But I looked on Craigslist and Ebay, and even the used ones are as noted, around $200 if they are modern. I wish I had more uses to justify paying that much, but I'm too cheap to spend that for my very occasional use.

I also Googled to learn the present state of the art in phone precision GPS. I thought it was farther along but it looks to me like this is still at the experimenter stage. For example 3~5 meter accuracy can be obtained IF you customize a precision-time application so your Android GPS ap can sync its clock to a frequently-updated master time standard. And the author of this precision clock software is asking for volunteers to host time servers in local communities all over the world, for the locals to sync to. That's definitely pre-release software development.

I never found an off-the-shelf real time precision GPS/mapping/waypoints etc ap. I think in theory the phones are capable of it, they triangulate satellites same as a real GPS and can triangulate cell towers also for a faster lock - but as I said the software to make precision observations and get the readings into an on-screen map - in real time - seems to still be in the hands of experimenters.

Mike, I looked at the QGIS website. I think their emphasis is developing software to read, integrate, overlay etc existing GIS data. I didn't see a section about acquiring data in the field, but it must be in there somewhere. I searched the current-release documentation for the word 'Android' and got only one hit:

... runs on Linux, Unix, Mac OSX, Windows and Android and supports numerous vector, raster, and database formats and functionalities....

so after that search I don't know what else I could use from their site, if I don't buy a Garmin or similar that outputs industry-standard readings.

Maybe the big farm GPS systems for tractor steering etc are all closed proprietary systems - my searching on phone GPS aps didn't find any overlap at all.

I guess I should explain that this inquiry is as much intellectual curiosity as it is farming necessity. It's not that difficult to just drive every second orchard row looking for the new trees. I just thought an application would be out there by now.

Still searching ...

 

[BillG_in_TX]

I like the idea of a Garmin handheld hiking GPS. Or maybe an automotive dashboard unit. But I looked on Craigslist and Ebay, and even the used ones are as noted, around $200 if they are modern. I wish I had more uses to justify paying that much, but I'm too cheap to spend that for my very occasional use.

Still searching ...

How about this one: Garmin Etrex Legend GPS Plus Accessories - almost New

 

[California]

How about this one: Garmin Etrex Legend GPS Plus Accessories - almost New

Hmmm...

My first search for info on that model shows it was put on the market over ten years ago. Amazon: Date First Available March 12, 2003
Knowing nothing about this technology, I'm a little cautious to buy something that many generations back. The reviews on Amazon reinforce this concern:

[2002 enthusiastic purchaser's 2008 update five years ago:]

Update - July 2008:

This was a good unit it it's day, but GPS technology has passed it by and the newer units are far better and don't cost much more. ... some of them are just a few bucks more than this dinosaur. [later models] have better reception, a color display, more map memory, fast USB connections and more. This uses the old serial connection that most PC don't even come with any more

But I'll be near there on Wednesday so maybe I should look at it.

Can anyone here comment on capabilities/limitations/obsolescence for that model?

Thanks for bringing that to my attention! :thumbsup:

 

[joshuabardwell]

For what it's worth GPS is capable of much higher accuracy, but civilian versions are limited to 3 meter accuracy to prevent someone from using it to guide in a missile or whatever. The military versions, which run off the exact same satellites, have much higher accuracy. So, basically, don't expect civilian versions to get any better unless the government changes its mind.

My understanding is that you're right about farm systems being proprietary. You put transmitters up and they're used for the precise positioning.

 

[California]

Is that the SA I was reading about? I thought they turned off that artificial, intentional timing 'jitter' a couple of years ago.

I think this is why amateurs now are writing software to track the remaining satellite internal-clock variations, applying corrections that were always available to military, in order to improve accuracy.

 

[joshuabardwell]

Is that the SA I was reading about? I thought they turned off that artificial, intentional timing 'jitter' a couple of years ago. I think this is why amateurs now are writing software to track the remaining satellite internal-clock variations, applying corrections that were always available to military, in order to improve accuracy.

You can read more about the topic here, if you like: GPS.gov: GPS Accuracy. Selective Accuracy (SA) was phased out around 2000, but there are other reasons why civilian GPS is not as accurate as military. In order to achieve military levels of accuracy, you need custom hardware to track a separate GPS frequency, and/or you need additional proprietary hardware and ground-based transmitters. With civilian receivers that only track a single frequency, accuracy can be increased to some degree, but not down to the level of military receivers.

However, I did see this, which was new information to me:

The ongoing GPS modernization program is adding new civilian signals and frequencies to the GPS satellites, enabling ionospheric correction for all users. Eventually, the accuracy difference between military and civilian GPS will disappear.

 

[MikeFarm]

Hi California

I like the idea of a Garmin handheld hiking GPS. ....
I wish I had more uses to justify paying that much, but I'm too cheap to spend that for my very occasional use.

I thought with that many trees it would be worthwhile to do things systematically with some appropriate technology to assist. Your correct in that GPS is they way to go but yes it's whether the software is out there to do what you want.

Mike, I looked at the QGIS website. I think their emphasis is developing software to read, integrate, overlay etc existing GIS data. I didn't see a section about acquiring data in the field, but it must be in there somewhere. ......
I guess I should explain that this inquiry is as much intellectual curiosity as it is farming necessity. ..... I just thought an application would be out there by now.
Still searching ...

The QGIS would work on your main Windows machine. You save the waypoints in the handheld GPS unit then the crappy Garmin software running on Windows downloads it from the GPS unit to your PC. It can save it in an open format called GPX (it's an plain text XML file of points). That can be opened and edited in any plain text editor. The GPX file can then be imported into the QGIS program. You can also if you have an aerial picture of your forest/farm have that as a layer in QGIS. So that's really all done in Windows. Use the Garmin in the field just to get GPS locations and also to navigate you to a specific spot.

Basically I think the Android phone wont cut it for what you want to do but a Garmin + QGIS will. Besides its always fun to play with technology on your farm

Mike
Mike

 

[BillG_in_TX]

Yes, I would probably pass on that eTrex Legend because of the serial interface, and look for something newer. Even if you have a serial port on your computer, it's a royal pain in the a** to work with. I have a Magellan Meridian of about the same vintage, and that is its biggest limitation. It still works great, though, and I have consistently achieved 3 meter accuracy with it over the years, as long as I was patient and the tree cover wasn't too dense. Here's a description of one project I completed with it: http://www.tractorbynet.com/forums/rural-living/62802-question-about-land-surveying.html#post701551