## 2 Data Description
### Ground Truth Data Collection  
The dataset is comprised of 320 points collected over 6 days between September 5 and 17, 2019 (Figure 5). A Reach RS+ (EMLID, St. Petersburg, Russia) single-band real-time-kinematic (RTK)-capable GNSS receiver was used. It is capable of receiving signals from several satellite constellations, including GPS, GLONASS, Galileo, QZSS, and Beidou. The Reach RS+ was mounted to the top of a fully extended surveying monopole with an attached bubble level to ensure the system would remain stable during data collection. The antenna height was measured as 2.065 m, which includes the height of the surveying monopole (2 m) and the phase center offset, which is the given distance from the bottom of the system housing to the position of the antenna within the housing (0.065 m). The ground truth data points were collected following an established protocol for the unit [13] and utilized incoming corrections from a SmartNet North America (Norcross, GA, USA) base station, located in Longueuil, Quebec (Station QCLO), with a baseline distance that ranged up to 16 km (depending on where in the park collection was taking place at the time). Corrections were received via NTRIP (Networked Transport of Radio Technical Commission for Maritime Services (RCTM) via Internet Protocol) [14] on a RTCM3-iMAX (individual master-auxiliary) mount. The RCTM3-iMAX utilizes real reference base stations to send the network corrections, which provides traceability and consistency for incoming corrections received by the GNSS unit [15]. Both GPS and GLONASS constellations with an update rate of 5 Hz were used. The manufacturer reported approximate accuracy of the Reach RS+ with an NTRIP stream baseline of <10 km with a FIX position is 7 mm + 1 mm/km and 1 m for an NTRIP stream baseline <30 km for FLOAT positions [16]. The necessary wireless hotspot was creating using a Novatel  
Figure 4: (**A**) The location of lies-de-Boucherville National Park (red circle) within the Canadian province of Quebec. Projection: Lambert Conformal Conic Projection, NAD83 (EPSG:102002)). (**B**) The five major islands that make up the extent of the park, shown in the St. Lawrence River near the Island of Montreal. Basemap is a PlanetScope Dove, image acquired on September 5, 2019. Projection: NAD83(CSRS)v7, EPSG:8254. Wireless MiFi-7000, and an iPhone Xs running the EMLID Reach application controlled the Reach RS+ rover. In order to respect the Societe des etablissements de plein air du Quebec (SEPAQ) park management team's request to limit the use of automobiles within the park so that park visitors would not be disturbed, a bicycle was used as the mode of transportation on the roads and trails, with the remainder of the sampling off-trail conducted on foot. In addition to the ground truth points, detailed field notes were also collected for each sampling point. These field notes included a site photo of the measurement point (along with the appropriate photo ID number), whether invasive _Phragmites_ was present or not,  
Figure 5: Map of fles-de-Boucherville National Park showing the 320 ground truth points. Red points indicate no _Phragmites_ was present at the measured location, and green points indicate that _Phragmites_ was present at the measured location. Areas where sampling was restricted due to active restoration efforts (purple) or private land (red) are also shown. Basemap is a PlanetScope Dove, image acquired on 5 September 2019. Projection: NAD83(CSRS)v7, EPSG:8254.  
basic site characteristics such as the type(s) of vegetation present, and more detailed notes regarding the location or characteristics of the site. The data underwent quality assessment and any improperly collected points were removed from the dataset, such as duplicate points (due to operator error) or points that reported horizontal standard deviation of 0 m. Ultimately 320 points were retained: 158 points where _Phragmites_ was present and 162 points where _Phragmites_ was absent.