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#1 2019-02-05 20:52:33

This Is A Display Name Desu
Member
Registered: 2018-11-19
Posts: 60

Altitude data

As I understand correctly, when most OSM-based application need to use altitude data in their application or rendering, they would choose to use some detailed publicly available dataset. However, sometimes those datasets are not detailed enough or not accurate enough for some particular area, is there anyway for OSM users to contribute to some sort of OSM-like services that can improve the accuracy of such data?

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#2 2019-02-05 23:25:00

alester
Member
Registered: 2011-09-21
Posts: 193

Re: Altitude data

I don't think so. Crowd-sourcing elevation data would be difficult due to inaccuracies in the measuring equipment. Consumer-grade devices are usually pretty flaky when it comes to recording elevation. My personal experience with Garmin handheld GPS devices and smart watches is that you can get a lot of variation in the readings. With two devices side by side, I've sometimes seen differences in the 50-100 metre range. I've also recorded tracks on these devices that show I was below sea level the entire time (I definitely was not). You'd need survey-grade equipment to get accurate readings, and you'd be limited in the areas that would be reachable to record data (mainly only publicly-accessible areas). I guess you could go out with your surveyor's GPS and record the elevation in a 5-metre grid in your local park, but it would take a lot of work to collect enough data in an area for it to be useful.

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#3 2019-02-05 23:55:55

This Is A Display Name Desu
Member
Registered: 2018-11-19
Posts: 60

Re: Altitude data

alester wrote:

I don't think so. Crowd-sourcing elevation data would be difficult due to inaccuracies in the measuring equipment. Consumer-grade devices are usually pretty flaky when it comes to recording elevation. My personal experience with Garmin handheld GPS devices and smart watches is that you can get a lot of variation in the readings. With two devices side by side, I've sometimes seen differences in the 50-100 metre range. I've also recorded tracks on these devices that show I was below sea level the entire time (I definitely was not). You'd need survey-grade equipment to get accurate readings, and you'd be limited in the areas that would be reachable to record data (mainly only publicly-accessible areas). I guess you could go out with your surveyor's GPS and record the elevation in a 5-metre grid in your local park, but it would take a lot of work to collect enough data in an area for it to be useful.

I am thinking about measuring the height different between a localized landmark with known elevation and different points close to the area. And then with the recent improvement in consumer grade GNSS system receiver technologies including the support of different GPS modes and also support of simultaneous use of multiple global navigation systems, it could also be getting to usable level of soon.
And then I wasn't talking about starting from zero, instead I was talking about base on existing data and modify from it

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#4 2019-02-11 20:01:03

Tordanik
Moderator
From: Germany
Registered: 2008-06-17
Posts: 2,351
Website

Re: Altitude data

There have been some related ideas related to crowdsourced elevation tracking in the past. For example, Peter Barth did a few experiments, e.g. using data collected by a delivery service, using a custom Android app. See this talk at FOSSGIS (sorry it's in German – not sure if these results are documented in English somewhere hmm). More recently, there's now the experimental OpenDemTracker.

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