# Can I use a smartphone to create a topographical survey?



## quatsch (Feb 4, 2021)

fI you start with the lowest point, you would accelerate for a time interval to a higher point & your latitude & longitude would then define this point in terms of x & y axis position, & altitude (the z axis).
x [position] = (1/2) a x t^2, so you'd need to know how many seconds it took you to get to the higher point.

In principle you could do this, but the errors would accumulate & they'd be large to begin with. You'd need commercial grade equipment to do this.

Even surveyors use a vertical pole with a moveable marker.


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## raylo32 (Nov 25, 2006)

One relatively easy DIY way to do this is with a drone. The survey software creates a GPS based flight plan including how to take and overlap photos. You send it off to fly the plan then send the data to the company who will stitch it all together into an aerial topographical map. IIRC the first one you do up to a certain size is free. I almost did this but then we found a state (Pennsylvania) website that pretty much has all this already created. All we had to do was go look it up, create boundaries and download it. For free. Not sure about other states but it is worth checking.


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## quatsch (Feb 4, 2021)

They will sell your info, probably to landscaping companies. 

Nothing is free except luv.

I asked for topological map of our area from the WaCo because a developer may wreck the drainage & cause flooding for our property.
Those deplorables ignored me. 
Maybe the courthouse has this info, for free.


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## SW Dweller (Jan 6, 2021)

My local county in Arizona has a site which if you ask for the elevations it will put them on the map for you. It also will measure to 0.00 of a foot. I tried it and got within 1 foot of the surveyed report. I think that is pretty good considering I am moving the mouse and the program is free.


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## quatsch (Feb 4, 2021)

Some places actually care about their citizens.


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## raylo32 (Nov 25, 2006)

This is the software and service I was going to try:

Maps Made Easy - Home


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## Half-fast eddie (Sep 19, 2020)

Ronnie, the acceleromter has nothing to do with your survey. That measures movement, like your speed driving a car. What you need is an accurate gps system that measures latitude and longitude, and elevation if you want a full topo. I had heard that civilian gps receivers are limited to 10 meter accuracy.


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## Ronnie833 (Jan 9, 2021)

Sorry for not being clear. I’m not trying to create a topo map of acres and acres of land. GPS, lat/long, satellite, etc. are overkill. I’m trying to measure a relatively small area in my backyard so I can understand drainage. My measurements are in inches. That’s why I thought an accelerometer would be perfect because I can record the exact position of the phone as it’s moved about.


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## raylo32 (Nov 25, 2006)

Might be better to just use a laser level... or even an old school line level... for that.  They make higher powered ones for longer distance and outdoor use. And you could create reference marks on stakes at your level's distance limit and start again from there. Repeat as necessary.



Ronnie833 said:


> Sorry for not being clear. I’m not trying to create a topo map of acres and acres of land. GPS, lat/long, satellite, etc. are overkill. I’m trying to measure a relatively small area in my backyard so I can understand drainage. My measurements are in inches. That’s why I thought an accelerometer would be perfect because I can record the exact position of the phone as it’s moved about.


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## huesmann (Aug 18, 2011)

SW Dweller said:


> My local county in Arizona has a site which if you ask for the elevations it will put them on the map for you. It also will measure to 0.00 of a foot. I tried it and got within 1 foot of the surveyed report. I think that is pretty good considering I am moving the mouse and the program is free.


Most counties have a GIS topo that you can access, typically at 2' intervals, sometimes 1', sometimes 5'.

What a survey does is create a digital terrain model. This is basically a point cloud, could be high res or low res, depending how close the points selected are to each other—each point has X, Y and Z coordinates. The DTM is then processed and a contour map is generated. The points for the cloud can be collected by ground survey, or aerial.


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## Ronnie833 (Jan 9, 2021)

raylo32 said:


> Might be better to just use a laser level... or even an old school line level... for that. They make higher powered ones for longer distance and outdoor use. And you could create reference marks on stakes at your level's distance limit and start again from there. Repeat as necessary.


Thanks for the suggestion. Yes, I know I _*could*_ do that. But then I'd have to buy all that equipment, take painstaking measurements, then transfer all that data to a drawing. I was hoping to just walk around with my phone


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## raylo32 (Nov 25, 2006)

Equipment is dirt cheap, especially the line level and a few stakes... less than $10. Laser levels maybe $30-50. Still basically dirt cheap. And you don't need precise measurements just to create fall lines and contours for drainage. At least IMO. Contrary to common belief our phones can't do everything yet! Good luck with your quest.



Ronnie833 said:


> Thanks for the suggestion. Yes, I know I _*could*_ do that. But then I'd have to buy all that equipment, take painstaking measurements, then transfer all that data to a drawing. I was hoping to just walk around with my phone


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## Ronnie833 (Jan 9, 2021)

raylo32 said:


> Equipment is dirt cheap, especially the line level and a few stakes... less than $10. Laser levels maybe $30-50. Still basically dirt cheap. And you don't need precise measurements just to create fall lines and contours for drainage. At least IMO. Contrary to common belief our phones can't do everything yet! Good luck with your quest.


Here's the research that says a phone _*can *_do it. I am looking for a DIY guy who might have actually done it. My quest continues...
(PDF) Making indoor maps with portable accelerometer and magnetometer


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## Half-fast eddie (Sep 19, 2020)

I read the paper. Interesting. But i still don’t understand why they need accelerometer data. 10 different people walking around the sample course are going to have 10 different accellerations and stride length.


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## raylo32 (Nov 25, 2006)

Looks like a proposed tool for time motion studies in buildings. I don't see any capturing of elevation data or other relevance to the OP's project.... unless the project is more of a phone project than a drainage project. ;-) There already are plenty of geotracking apps out there that will overlay positions on a map. But they are probably only location, not elevation.


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## Half-fast eddie (Sep 19, 2020)

Moasure - Motion based measuring technology


Moasure is a revolutionary new measuring technology that measures by sensing its position and movement in three dimensions. It uses inertial motion sensors to measure distance, height, level, angle, area and volume in a single measurement, simply by moving from one point to another.




www.moasure.com


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## raylo32 (Nov 25, 2006)

Cool, but again only location, space and area. Not elevations.



Half-fast eddie said:


> Moasure - Motion based measuring technology
> 
> 
> Moasure is a revolutionary new measuring technology that measures by sensing its position and movement in three dimensions. It uses inertial motion sensors to measure distance, height, level, angle, area and volume in a single measurement, simply by moving from one point to another.
> ...


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## Ronnie833 (Jan 9, 2021)

The moasure app seems to do the trick. I just installed it on my phone. It's does not build a topo map, but it does calculate the elevation difference between two points. Perfect! Thanks for the tips, guys.


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## raylo32 (Nov 25, 2006)

Interesting, that was not apparent from the description. What is the vertical resolution? I mean how small a difference can it show?



Ronnie833 said:


> The moasure app seems to do the trick. I just installed it on my phone. It's does not build a topo map, but it does calculate the elevation difference between two points. Perfect! Thanks for the tips, guys.


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## Ronnie833 (Jan 9, 2021)

raylo32 said:


> Interesting, that was not apparent from the description. What is the vertical resolution? I mean how small a difference can it show?


It has a 1/2” resolution. Place the phone at point A. Then place the phone at point B. It will tell you the elevation difference. The app is free for IOS or Android. It can also measure distance and slope.


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## A Squared (Dec 19, 2005)

Ronnie833 said:


> My phone has an accelerometer. Theoretically, it can tell me precise movement along x, y, and z axis. So, can I place my phone throughout my property then analyze the recorded data to create a topographical map? Surely this has been done already because it seems like such an obvious use of an accelerometer. Has anyone done this?



Well, the underlying concept is more or less sound. You can do surveying measurements with inertial measurement systems. Back before the advent of GPS, I worked as a surveyor for a company whcih did surveys in remote areas with inertial survey systems. We transported them around in helicopters and trucks. They contained accelerometers on a gyro-stabilized gimbaled platform. The system we used was built by Litton systems.


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## raylo32 (Nov 25, 2006)

Yup, the concept it sound. Even used since the 1960s to navigate submarines whilst underwater between satellite (or otherwise) hard positional fixes... in that case mostly concerned with X and Y planes, not Z. Those early systems had huge physical gyros and were made by Sperry.

Nowadays there are plenty of micro inertial sensors and gyros like for phones and drones. Whether the sensor sensitivity and software can accurately resolve very small differences like in your yard IDK. Seems the best of all worlds would be to overlay inertial data onto a GPS defined grid. The phones have the hardware so they should be able to accomplish that in software.

Submarine navigation - Wikipedia



A Squared said:


> Well, the underlying concept is more or less sound. You can do surveying measurements with inertial measurement systems. Back before the advent of GPS, I worked as a surveyor for a company whcih did surveys in remote areas with inertial survey systems. We transported them around in helicopters and trucks. They contained accelerometers on a gyro-stabilized gimbaled platform. The system we used was built by Litton systems.


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## Frank W (Jan 13, 2022)

Ronnie833 said:


> The moasure app seems to do the trick. I just installed it on my phone. It's does not build a topo map, but it does calculate the elevation difference between two points. Perfect! Thanks for the tips, guys.


Hello,
Actually yes, I use the *PRO-SUITE* software to create topo maps with this, Here's how:
1. After you walk to measure the yard just export as a .csv file into *Pro-Suite* and it will *create* both the 1D topo and 3D terrain plan (must use the Moasure ONE device with Plus export).
2. You can then print (or pdf) the plan to any scale and/or plan size (paper size).
3. You can also draw directly on top of the plan to create both 1D plan & 3D plan (complete with all the terrain changes already drawn, it creates a 3D terrain) to create your landscape, hardscape, or professional pool/spa plans, etc.
You can find 'em online at: PoolTemplates.com


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## Frank W (Jan 13, 2022)

SW Dweller said:


> My local county in Arizona has a site which if you ask for the elevations it will put them on the map for you. It also will measure to 0.00 of a foot. I tried it and got within 1 foot of the surveyed report. I think that is pretty good considering I am moving the mouse and the program is free.


Sounds good, do you know the URL of that AZ site please?


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## Frank W (Jan 13, 2022)

SW Dweller said:


> My local county in Arizona has a site which if you ask for the elevations it will put them on the map for you. It also will measure to 0.00 of a foot. I tried it and got within 1 foot of the surveyed report. I think that is pretty good considering I am moving the mouse and the program is free.


Sounds good, what website is that please? Thanks AZ


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