Attitude measurement

When mapping the location of structures in the field, it can be helpful to also document their orientation (a.k.a attitude) in three dimensions. Tracking this information can help contextualize features in their surrounding landscapes or track drift and tilt of structures over time.

While not required, we recommend using the Attitude attribute type whenever collecting data with the Attitude Tool. Paired together, these tools offer a highly reliable, quick, and easy way to both measure and record orientation data in your data collection forms.

Adding Attitude Attributes

When creating a new feature class, you can select "Add Attribute" and choose the "Attitude" type from the list:

After selecting the attitude type, you have a few options for formatting your attitude. If the feature class you're adding is meant for planar features, you'll want to choose either Strike and Dip or Dip and Dip Direction. If the feature class you're creating is for collecting linear feature data, you'll want to select Trend and Plunge.

It can also be helpful to set the Label and Rotation configurations for your feature class to the Attitude attribute you just selected.

When using an attitude attribute for a label, the value will be equal to the inclination component, meaning either Dip or Plunge. When using an attitude for rotations, the value will equal the directional component of the attribute (strike, dip direction, or trend) and rotate the feature's icon between 0-359 degrees to align with the compass heading.

The Attitude Measurement Interface

To access the attitude measurement tool, tap on the icon in the bottom right corner of the screen that looks like a circle with a T-shape (the strike-dip symbol) inside. If you don't see this icon, then the attitude tool is currently disabled. To enable it, open the Options panel, and look at the Map Settings, then find the toggle switch for "Display Attitude Tool".

Tapping on the icon will open the attitude measurement screen, and if this is your first time it will be in the Planar configuration. Let's discuss each part of the interface from top-to-bottom:

Settings Button

This will open another window with additional configurations for the attitude tool. At the moment, there's just one configuration that allows you to toggle between the Strike and Dip format and the Dip and Dip Direction format. Keep in mind that using the Create Button with your measurement will convert the measurement to whatever format is configured with the selected Feature Class, regardless of what format the attitude tool is using. This conversion is done using the Right Hand Rule, meaning that strike will always be measured according to whichever direction would make the dip direction 90 degrees clockwise from the strike.

Measurement Type Toggle

Allows you to switch between the planar and linear measurement interface. The Linear interface is discussed later in this article.

Dial Indicator / Stereonet

This presents a visual representation of the attitude measurement. In the Planar configuration, the dial shows a variation of a stereonet. The strike-dip indicator rotates based on the orientation of the device, so it always shows the direction of the dip being measured as well as the horizontal plane. The curved line across the surface represents the magnitude of the dip. In the Linear configuration the dial represents a traditional clinometer or angle gauge, and an example is shown later in this article. Tapping on the dial indicator will lock in the current measurement.

Here's an example of the clinometer dial when using the linear measurement configuration:

Device Heading and Magnetic Declination Indicator

This dial shows you the current device heading as the Operating System sees it, as well as the magnetic declination according to the Operating System. This indicator is meant to provide a quick way to verify that your device's compass is calibrated correctly based on your current location and heading before taking a measurement.

Lock Indicator

When the center of this button is blue and the dial hand is red, as in the example above, the measurement is unlocked and is constantly updated. When the center of the button is white, with the outer ring blue, and the dial hand blue, the measurement is locked in and won't change until it is unlocked.

Value Readouts

These two boxes show the values of the current measurement in plain text, to make reading the instrument as easy as possible.

Feature Class Selector

This box will show the currently selected feature class, if there is one. The selected Feature Class is the one that will be created when tapping the Create ("Add Point") button. Tapping on the box will allow you to navigate through your Feature Class Datasets to pick a Feature Class that has an attitude attribute.

Create Button

This button will create a new instance of the selected feature class placed at your current location and automatically fill the feature's attitude attribute with the current measurement.

How to take a planar measurement

After you've opened the attitude measurement tool and verified that your compass is calibrated, recording a new measurement is easy. The goal is to align the plane of the device with the plane that you want to measure, so they're congruent. This can be as simple as laying or holding the device on the surface to be measured and then tapping to lock the measurement in. In situations where this isn't possible, like when measuring a particular rock layer sandwiched within an outcropping, you can also hold the device up and align it visually to the plane, making a best-guess approximation of its form, and tapping the dial to lock it in once you're satisfied with the alignment.

How to take a linear measurement

Linear measurements work similarly to planar ones, except that instead of aligning the plane of the device to the feature being measured, we need to align the long axis of the device to the feature. This can be done by placing the long edge directly on top of the feature being measured, or by holding the device flat on the surface and aligning the edge to the feature. Since the orientation of the axis will be the same either way, you'll get the correct measurement. It also doesn't matter which of the two sides on the long axis you use to measure, as the trend and plunge of the two sides are always equal, so use whichever is more convenient for you.

After taking your measurement and adding a point with it, you should see your new feature rendered on the map, labeled and rotated as applicable:

How do I update an existing feature with a new measurement?

There are two ways to update an existing feature's attitude attribute, both easily accessible from the Feature Attributes Panel.

1. You can tap directly on the values of the attitude attribute to open a window that allows you to type in the values directly. This is particularly helpful if you want to fall back to a manual compass and clinometer.

1. You can tap on the strike-dip symbol next to the attitude attribute's values to open the attitude measurement view in Update mode, where the save button updates the original feature instead of creating a new one.

What happens when I export an Attitude attribute?

Exporting and importing attitude attributes in the .tgis file format works seamlessly, the data will be restored exactly how it was before the export. For external file formats like KML, Shapefiles, or GeoJSON, the attitude attribute is split into two separate number fields, and the field names will depend on the attitude format. In general, they'll follow the format {attribute_name}_{component_name} like so:

• "Attitude_Strike" and "Attitude_Dip"

• "Attitude_Dip_Direction" and "Attitude_Dip"

• "Attitude_Trend" and "Attitude_Plunge"

For shapefiles where field names are limited to 10 characters, the names are abbreviated like so:

• "STR_Attude" and "DIP_Attude"

• "DIR_Attude" and "DIP_Attude"

• "TRND_Attde" and "PLNG_Attde"