Mapping with GPS and a Smartphone

[hpinson]

We just entered the world of smartphones, and perhaps I am expecting too much.  Are there apps for doing GPS mapping? As in; here is a survey marker on the ground, and I would like to record its latitude and longitude within six meters or so, using the phone built in GPS?  This phone happens to be a Samsung Galaxy SIII running Android 4.

[UK4X4]

pretty sure there's an Ap for that !

I'm not an android chap- but pretty sure you'll have some topo mapping aplications

MotionX is one for iphones-

a phone gps would get you close enough to find in the future, but a dedicated GPS would give you better results
and if you have tree cover you may need to get creative.

X point walk 20 paces north under the tree's for example

[hpinson]

Hmm. What's the difference between a phone GPS and a dedicated GPS-- why would one be more accurate than the other?

Would this thing work out in the sticks where there is no reliable cell coverage or local wifi - from satellite coverage alone?  I'm guessing no, that having cell towers at hand is some key to getting this working.

I just found one Android app that seems quite capable: Ullysee Gizmo

http://www.appbrain.com/app/ulysse-gizmos/com.binarytoys.ulysse

It does lat / long/ UTM / Altitude / compass direction both magnetic and true / declination / inclination and a bunch of other stuff, showing satellites available, claimnig 3 meter accuracy, and lets you save waypoints, presumably to Google KML.

It found my street address right off, from inside the house and claims it sees satellites from indoors.  Hmm.  Mind blowing stuff!

[Erin]

Do you have to have a simultaneous data connection to run it, though? 
Just curious as I've wanted such a thing too, but most of the time, anywhere I want to map, doesn't have a signal to run the data connection...

[hpinson]

Do you have to have a simultaneous data connection to run it, though? 

Generally, anyplace I want to map, no - in and out 3G service at best and at worst one or no bars. Data connection is spotty or not available at all.

This article sheds a little light.

http://www.am22tech.com/s/22/Blogs/post/2011/06/22/Does-GPS-In-SmartPhone-Use-Your-Internet-Data-Plan.aspx

So it appears that the smartphone is in fact seeing GPS satellites, that GPS positioning service is freely available, and with the right software should be able to log points... but unless a map is available for download requiring a data connection (like Google Maps) you cannot really use those points in real time (perhaps you could if you had some other map service maps stored locally).  That would be ok for collecting data points? All I want too do is collect and store lat/ long waypoints (presumably in a KML file) that map my property boundary, and can be used later to plot to a (Google) map.  Not sure what Android software would do this. Ulysse Gizmos may; I will have to report back on this.  Any real experiences would be appreciated.  Gonna change the game for surveying if this is possible with a smartphone, with reasonable accuracy.

[Canvasman]

I have backpacker lite on my galaxy. Works so/so, does log lat and long. When in the middle of national forest, did not work well. Will not be as accurate as a dedicated GPS. My understanding is the number of satellites they grab onto.

[MountainDon]

reasonable accuracy??  Depends on how reasonable is defined. I have taken a dozen or so reading at each of the 6 surveyor set stakes that bound our property. They generally make a circle with a radius of about 6 to 9 feet. That's with a very good dedicated GPS. It's still not good enough for any legal boundary setting purposes. Not sure of all the differences but the ones the surveyors use are priced in the thousands. I don't think smartphones are going to put any surveyors out of business.

[hpinson]

Point taken. Mine says 3 meters accuracy, and I'm very unsure how accurate the altitude is.  But just you wait MountainDon... Give it a few years.

10 satellites are in view right now according to the phone (inside the house). Roofs don't affect like tree-cover? I remember that the Trimble units fell apart when under broadleaf trees, at least in the early 90's.  Many fewer satellites were available then though and there was introduced offset.

[MountainDon]

The altitude can be off by hundreds of feet from experience. The vertical accuracy is supposed to be within 1.5 times the horizontal accuracy. All I can say that with the GPS sitting at the cabin, same spot over hundreds of readings the altitude varies from 8785 to 8805... mostly around 8790   

Those who use GPS altitude to aid in landing their small plane should have their insurance policies paid up at all times.

[UK4X4]

mapping for phones

depending on the software some of them allow you to cache maps on your device

These cached maps can be used without data services.

I have two garmin devices and my phone

I use the dedicated device - better signal- better results to date than my phone- but within a year i guess they'll be obsolete

being that I offroad - TOPO maps are what i usually use rather than google as the roads are'nt shown that I use

[tommytebco]

I'm a hiker. I tried to use my phone on the trail. It has been marginal, at best , for me so far.

If you are out of coverage, you have to cache the map data and link that data to the GPS/Map program. It has been a hard learning curve for me. But, maybe that's just me.

Anyway, I believe after you had competency, you could mark the survey spot and record your track as you walked the edges of your property. Getting competent is another story.

[Rob_O]

being that I offroad - TOPO maps are what i usually use rather than google as the roads are'nt shown that I use

I have a Magellan GPS I can sell you, it has directed me to so many "non-roads" it should have been named "Columbus" 

[firefox]

Too bad you can't use the Military GPS system. Accuracy to within 1 CM.
Bruce

[Native_NM]

I went looking at some property recently.  This is where I parked the truck.  App is Motion-X on an iPhone. 

I also have a Garmin with a helix antenna. I marked the waypoint on it, also.  They were almost identical. 

My truck has a GPS.  It was the least accurate. 

When I got home I uploaded the waypoint to Google Earth and Garmin Basecamp.   They are amazingly accurate.   

Motion-X will work without a cell signal.  With a cell signal it can send data, waypoints, email your position, etc.

For a couple bucks it's amazing. I use it when I travel as a backup.  It's just easier than carrying all the gear. 

I also have their live guidance app.  It requires a subscription to use live guidance, but it's only $20 a year.  It is actually better than the Garmin's they rent with the cars. 

As far as accuracy, in every test I've performed the iPhone is pretty darn accurate.  I tested at Fenton Lake and it was as accurate as my handheld.  WAAS is good enough for me. 

[hpinson]

Cool-- good info. That app seems very similar to Ulysee Gizmos on Andriod-- maybe a bit more intuitive to use, but similar features.  Looks promising!

[waggin]

Hmm. What's the difference between a phone GPS and a dedicated GPS-- why would one be more accurate than the other?

Would this thing work out in the sticks where there is no reliable cell coverage or local wifi - from satellite coverage alone?  I'm guessing no, that having cell towers at hand is some key to getting this working.

I just found one Android app that seems quite capable: Ullysee Gizmo

http://www.appbrain.com/app/ulysse-gizmos/com.binarytoys.ulysse

It does lat / long/ UTM / Altitude / compass direction both magnetic and true / declination / inclination and a bunch of other stuff, showing satellites available, claimnig 3 meter accuracy, and lets you save waypoints, presumably to Google KML.

It found my street address right off, from inside the house and claims it sees satellites from indoors.  Hmm.  Mind blowing stuff!

I'll have to check that one out...Thanks!  I have all four corners of my property staked, but topography, distance, and brush make finding where the property line is between corners very difficult. 

I have a Magellan GPS I can sell you, it has directed me to so many "non-roads" it should have been named "Columbus" 

If you type in the location, "West Indies", does it direct you to India or the Caribbean?  Enquiring minds want to know.   

[tristan]

external bluetooth GPS receivers can also be used to improve accuracy with smart phones.  I use a Garmin GLO with my android tablet and it does fairly well under dense tree cover.  Besides having a better antenna, the advantage of an external receiver is that you can put it on your hat so that your body isn't blocking the sky.

there are several free apps that can be used to map areas and also to navigate to certain coordinates. 

[Rob_O]

If you type in the location, "West Indies", does it direct you to India or the Caribbean?

Have not tried that, but I have a feeling I'd wind up on the West side of Indianapolis motor speedway

[Cowboy Billy]

Last year I wanted to do the same thing. Convert rods and chains of my property description to gps. But I couldn't find any way to. And I think its partly due to continental drift. I do know the Army Core of Engineers resurvey their monuments ever so many years to see if they have moved.

GPS accuracy. Under good conditions a handheld gps is good for less than 32 feet. While it can come closer than that. Thats its base inaccuracy. The accuracy listed on the gps unit is how far outside that base 32 feet it is. So say your unit is saying it has a 5' accuracy. What that really means is 5' + 32' equaling 37'

The very accurate GPS I use at work on my bulldozer. Uses a ground station at a precisely marked spot with a radio link to the dozer that works with the gps to find its location.

A side note on monuments/survey points. They might not be right on the property line. Lets say property line is right in the middle of a gravel road. The surveyor can put the monument off to the side of the road so it doesn't get damaged. And just make a note of it in his logs. What I don't know is if the offset is marked on the monument or if its the exact location of the monument but you have to know you have to add or subtract a certain number of feet to get the correct property line.

http://earthmeasurement.com/GPS_accuracy.html

Billy

[Woodswalker]

I am finding this thread very useful.  Have a LG phone, running Android, so downloaded Ulysee Gizmos from the Google app store.  Features seem to work well here at my home here near Olympia, WA.  Altitude reads low (5m), when I'm actually at ~200ft.  Plan to use it to locate two corners of 20 acres I have a cabin on in Ferry County, NE WA.  The county has a nifty online system called tax/map sifter that shows property and other boundaries on a photo base similar to Google Earth.  My parcel is 660ft x 1320ft, with boundaries oriented N/S & E/W.  I know the staked locations of two corners at one end, but not the other.  The system gives coordinates for any place you put the pointer.  I've recorded coordinates for all four corners.  Next spring when I get back over there, I'll check the accuracy of those with what I get in the field at the two known stakes, using the phone.  Differences will be recorded, and applied to the recorded coordinates for the other end of the parcel.  Can then take the phone up there, and, using the adjusted coordinates on the phone, look for the unknown stakes.  There is no canopy at any of the corners, which should help accuracy.  We shall see...

[Native_NM]

I had a survey of our commercial property in December.  Full topo also for a hydrology report.

The company that did the work had some nice equipment.  I asked him about the hand-held stuff and he said he's used it for rough work but it's not valid for surveys.   I have both a Garmin with WAAS and an iPhone.  We did a test just for fun. My Garmin had me about 6 feet away from a known survey point which I thought was amazing.  My iPhone and app were 22 feet away. 

His big unit is a tripod mounted deal with antenna that went up about ten feet.  He claims he is accurate to the centimeter after collecting the data and then processing it through a mapping software. 

[firefox]

It sounds like he is tapped into the Mil satalites. They may have opened up the
info for civilian use. It takes a special coding to make it work.
Bruce

[MountainDon]

.... from http://www.gps.gov/applications

To achieve the highest level of accuracy, most survey-grade receivers use two GPS radio frequencies: L1 and L2. Currently, there is no fully functional civilian signal at L2, so these receivers leverage a military L2 signal using "codeless" techniques.

The ongoing GPS modernization program is adding a dedicated civil signal at L2 that supports high-accuracy positioning without the use of military signals. The GPS program is also adding a third civil signal at the L5 frequency that will enhance performance even further. After 2020, the government will no longer support codeless access to military GPS signals.

[cbc58]

I attended a business startup event last fall where people get together and try to develop a working business in one weekend.  There was a team developing an app. and their website is here:  www.fieldflag.com   The person heading it had degrees in GPS/GIS and was telling me that there are groups of satellites that tie in together and the more connected, the more accurate measurements can be.  I guess there are discussions to group some Canadian satellites soon which may substantially increase accuracy for the common user.   They can get within 3-6 meters on average - which sounds like the other apps out there.   Chip technology and tower triangulation is also improving.

I have seen people move survey pipes and markers - so not sure I would trust this type of thing for a formal boundary line decision.  The premise behind fieldflag was for local govts. to inventory things like park benches, tables, signs and other owned property.   

[firefox]

Thanks Don for clearing that up!
Bruce