Collect Elevation with ProjectZ Tool

Since the ArcGIS Pro 1.4 release, ArcGIS supports the transformation of height values between vertical coordinate systems. This is useful for users who are interested in the vertical component of geometry, like water utility users. We can expand the users of this capability into Collector users via ProjectZ (https://github.com/Esri/collector-tools/blob/master/CollectorUtils/project_z.md) geoprocessing tool.

ProjectZ tool is a custom tool built on top of the Project tool (https://pro.arcgis.com/en/pro-app/tool-reference/data-management/project.htm), which exposes the vertical datum transformation capability. It runs in ArcGIS Pro.

Note: Vertical datum transformations require files that aren't installed with ArcGIS Pro. Download and install the ArcGIS Coordinate Systems Data setup for ArcGIS Pro through My Esri if you haven't already. It contains the data files required for the GEOCON transformation method and vertical transformation files for the United States (VERTCON and GEOID12B) and the world (EGM2008).

The idea of collecting high precision elevations with ProjectZ tool is to collect the height above ellipsoid value as a point feature attribute and then "post-process" those attributes value with ProjectZ tool using the latest vertical datum transformation in ArcGIS Pro.

We use ArcGIS Pro 1.4 to demonstrate this workflow. Just make sure you have installed ArcGIS Coordinate Systems Data setup.

Let's assume you have collected a point feature class with GNSS metadata (check http://doc.arcgis.com/en/collector/android/create-maps/gps-config-metadata-storage.htm for additional help) and you collected it using a correction service based on NAD83 2011 coordinate system. The receivers output positions based on NAD83 2011, so the Latitude, Longitude, and Altitude in the GNSS metadata (which are raw data from GNSS receiver) are based on NAD83 2011.

Download Collector-Tools (https://github.com/Esri/collector-tools) and open ProjectZ geoprocessing tool in ArcGIS Pro.

Select your collected feature class as "Input Features", and "Input Coordinate System" is the correction service coordinate system. I use NAD83 2011 base station, thus "Input Coordinate System" is NAD 1983 2011 for both X, Y, and Z. For Z value, NAD 1983 2011 is an ellipsoidal-based vertical datum.

X-value, Y-value, and Z-value are auto-populated from the GNSS metadata fields.

Then you select the location of the output feature class you would like to save as "Output Features" and select its "Output Coordinate System". If you are interested in elevation, the coordinate is not based on ellipsoidal. It is a gravity-based vertical datum. NAVD 1988 is selected.

Geographic Transformation is auto-populated with geoid12b model. Here is the final configuration of ProjectZ tool:

Run the tool. The output database has a Z-enabled feature class with vertical datum NAVD 1988. The elevation is shown as the Z-value of the geometry. The Latitude, Longitude, and Altitude attribute values are left as the raw data.

With this ProjectZ geoprocessing tool, you can post-process your feature class with accurate elevation as Z-value. This will help your workflow to collect elevation with Collector.