Getting started with configuring GNSS devices in ArcGIS Pro
A great new feature introduced in ArcGIS Pro 2.7, is GNSS (GPS) location support. You can now connect a GNSS device to ArcGIS Pro to assist with feature creation and navigation within a map or scene. This article aims to get users started with some typical connections, as well as provide suggestions for those who would like to test the feature with their phone, rather than going out and purchasing an off-the-shelf receiver.
As you may know already, there are already few options for integrating GNSS positions and data collection within Windows applications, including;
- Collector for ArcGIS - Windows, which allows for simple feature capture.
- Survey123 has Windows-based field app and the ability to capture forms within a Windows web browser.
- ArcGIS Web AppBuilder provides the ability to create and use location-enabled web mapping apps that work within Windows web browsers.
However, these products don’t currently allow you to create and edit points directly within the desktop interface which is now possible in ArcGIS Pro 2.7. The ability to quickly orient and update your location in a project, while in the field, rather than using the search or pan/zoom to feature will assist users who spend time working with ArcGIS Pro in a field setting.
Hardware considerations
Until recently, Microsoft Surface, Panasonic Toughbook, and a small number of other devices were the only options for users who require portability, performance, and perhaps, integrated GNSS in a Windows environment. Today, most laptop manufacturers produce 'ultraportable' laptops and tablets, which run on Windows 10 and comfortably meet the System Requirements for ArcGIS Pro 2.7.
The GNSS position data is streamed to ArcGIS Pro using NMEA messages over a COM port. You can use several methods to bring location into your Windows device – I have provided an overview of three below.
- Connect a GNSS receiver directly to your computer using Bluetooth
By connecting a GNSS receiver directly to your computer using Bluetooth, then allowing positions to stream through to ArcGIS Pro, you can achieve RTK (1-2cm) positional accuracy within ArcGIS Pro. If you have not already set up your receiver work with Collector for ArcGIS, or Survey123, you'll need to configure your receiver. Most receiver manufacturers provide the option to configure NMEA output through the webserver or controller on the receiver - you will need to refer to the user manual for more information.
Just note also that COM ports can only be used by one software at a time, so it is impossible to work with location-enabled in Collector for ArcGIS and ArcGIS Pro on the one Windows device at the same time.
- Connect a mobile device to your computer using Bluetooth
Like the process described above to link a GNSS receiver, it is possible to connect your Mobile Phone to your computer to stream NMEA positions to ArcGIS Pro. Although some mobile devices can now produce highly accurate positioning using RTK, it is typical to expect around 5-meter accuracy in favourable conditions.
There are several apps available which allow for the streaming of NMEA locations over Bluetooth. Some have associated costs for full feature access, others have ads, but I've found the simplest, with a handy wizard to set up your COM port is 'Bluetooth GPS Output' for Android. It is a good starting point if you're looking to use this workflow within your organisation.
- Use your computers' onboard GNSS to provide locations to ArcGIS Pro.
Some ultraportable laptops have integrated GNSS, which can be utilised by ArcGIS Pro directly. Typically, the COM port is configured within the device's location setting, which is determined by the GNSS driver on the computer. Refer to the manufacturer instructions for more information if you are pursuing this method.
Once you have created the COM port and started streaming NMEA, it is a relatively simple process to configure ArcGIS Pro to use the location data.
- Go to ‘Project’ -> ‘Options’ -> ‘Device location’
- Select the COM device from the dropdown list, setting the accuracy threshold, if you need.
- In a project, select the 'View' tab, then press 'Enable Location.'
Some additional considerations when setting up GNSS in ArcGIS Pro.
If you are creating new features, the geographic coordinate system on the feature class that you are editing must match the geographic coordinate system selected in the device properties. To change the device coordinate system, go to ‘Project Options’ -> ‘ Device Location’ -> ‘Properties’.
This setting should also match the coordinate system on the GNSS receiver if you require accurate locations. For example, if you are configuring a Trimble R10 to provide locations, you should set GDA2020 on the Trimble, in the ArcGIS Pro settings, and in the point feature class coordinate system.
The properties window also allows for an antenna height to be specified. This is the distance from the antenna to the ground. If using your phone or computers’ onboard GNSS, this can be measured and added into the settings. If you are connecting to an external receiver, it is important to know whether the antenna height is pre-corrected into the NMEA position. Most GNSS receiver manufacturers, by default will stream elevations to NMEA based on the phase centre of the antenna, but some others will allow for the configuration of antenna heights and offsets, which are incorporated into the position to provide ground elevations. It’s good practice to check your receiver documentation, or test on a known benchmark to confirm.
More information on the process of setting up the device can be found here.
There is an excellent blog post by Greg Lehner 'Collect data in the field from your GNSS device with ArcGIS Pro' which I'd also recommend reading for more information about the functionality of this feature.
Thanks for reading. Feel free to drop any questions or comments in the comments below.