# altitude

## High-Level Explanation

This signal is from the GPS system and gives the distance above sea level that the device is currently located. When this signal is positive, the vehicle is above sea level, and when this signal is negative, the vehicle is below sea level.

## Enables

Estimating road grade based on the change in altitude. However, the frequency in records must be considered when attributing a change in altitude to a specific road. If record A occurs at 12:00:00pm and has an `altitude` of 100 meters and record B occurs at 12:30:00pm and has an altitude of 200 meters, the difference in time is too large to assume the road near record B has a positive incline.&#x20;

## Enabled By

## Known Quirks

## Visualizations with Explanations

<figure><img src="https://3212476574-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Foh9c3w7RI0Bl5tVCxcyz%2Fuploads%2FoioX1QWFU9N83UhwfiFp%2Faltitude_mountain_hwy.png?alt=media&#x26;token=0b7e7c57-e3bd-46bd-9eea-a249be8188cd" alt=""><figcaption><p>Plot of <code>altitude</code></p></figcaption></figure>

<figure><img src="https://3212476574-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2Foh9c3w7RI0Bl5tVCxcyz%2Fuploads%2FRcPDy1YdsvmCB7DS6eCr%2Fimage.png?alt=media&#x26;token=f4307829-7151-450f-86fe-cb3240cab66d" alt=""><figcaption><p>The trip with altitude shown above traveled southwest on HI 61</p></figcaption></figure>
