2022 Workshop Q&A: Responses to “Arrow GNSS and ArcGIS Field Maps” Questions (Part 2)

Questions and Answers from “Arrow GNSS with Esri ArcGIS Field Maps,” an Eos workshop with special guest Doug Morgenthaler from Esri

On October 18, 2022, Eos hosted a workshop, “Eos Arrow GNSS and Esri ArcGIS^® Field Maps (2022 Live Training),” with Esri. The workshop included an overview of GNSS, a history and roadmap of ArcGIS Field Maps from Esri guest Doug Morgenthaler, an indoor demonstration of setting up an ArcGIS Online web map for high-accuracy data collection, an outdoor data-collection demonstration, an ArcGIS Dashboard look at the data collected live, and a Q&A wrap-up.

Below are the questions our panelists were unable to answer during the live Q&A section.

Note: If you did not attend the above workshop, please sign up for our monthly newsletter to be notified about upcoming opportunities.

(Please use a work-domain email address, or there might be a delay or issue with providing you the recording.)

Below is a transcript of the questions submitted during the workshop, with answers from our panelists:

Meet Our Panelists

Q&A (Part 2 of 2)

1. Housekeeping Questions

1.1 MULTIPLE: Could you please share the panelists’ slides?

Eos Positioning Systems: Yes! Please find the two slide decks used available here for download:

2. Eos GNSS Questions

2.1 ALEX: I would like to know about best practices for collecting GNSS attribute data on line and polygon features (adding GNSS fields to layers within ArcGIS Pro).

TYLER: The next release of ArcGIS Pro will have a tool for adding GNSS attributes to line and polygon features. Currently, you have to create the layer in ArcGIS Online or run this Python notebook on an existing feature layer.

2.2 KATELYN: How do I figure out what my GNSS receiver is using to do my location profile?

TYLER: If you are not connected to an RTK base station you can be confident that your GNSS coordinate system in the location profile should be set to default or ITRF2014.

If you are connected to an RTK base station in the United States you can assume that the GNSS Coordinate System is NAD 1983 (2011). There are some exceptions like California. The best way to confirm is to ask the base station (or network) operator. If you’re an Arrow user and you’re not sure, you can contact our technical support team.

2.3 WILLIAM: Tyler, any advice for placement of antenna when using an Arrow in hand (with tablet bracket)? Any advice for maximizing accuracy under a tree canopy?

TYLER: Keep in mind that your body will completely block any satellite signals. Fully extend your arms away from your body while using the handheld receiver and hold it so that the antenna is leveled at least at shoulder level. This will give the antenna the best view of the sky.

Tree canopy is tough. Use the technique described above as well as keep the receiver on and tracking while you move through the forest. If you turn off the receiver or loose lock, then the receiver has to re-acquire the signal — which is more difficult to do under tree canopy. It’s easier for the receiver to hold on to the signal then to re-acquire it.

2.4 JASON: Regarding streaming RTK differential corrections via cellular, UNAVCO provides a WGS stream while some other state providers run a NAD83 solution. Does this differential stream change the GNSS coordinate system in the location profile? Do these varied base positioning streams affect receiver accuracy, and how can it be mitigated?

TYLER: Yes, if your base station is referenced to WGS84 instead of NAD83 you will need to set the GNSS coordinate system parameter to match. UNAVCO uses their bases primarily for monitoring tectonic plate movement. My understanding is that their reference positions are dynamic whereas most networks keep their reference positions locked into the NAD 1983 (2011) datum at epoch 2010.0. Keep that in mind when using them for high-accuracy mapping.

2.5 LAUREN: Can you go over how to transform the ellipsoidal altitude from the “ESRIGNSS” to the map coordinate system (say NAVD88). For example, in the “Display XY Data” tool when trying to restore point geometry?

TYLER: The math is simple addition/subtraction, but you’ll need to know the geoid separation value at each point. Eos Tools Pro will handle this for you in real time in the field so that you don’t need to do any post processing. Set the elevation type to “Orthometric” then select GEOID18. The Z-values of the point geometry will now be populated with NAVD88 values while the ESRIGNSS_ALTITUDE field will retain the original ellipsoidal height from the Arrow.

If you must post-process, you’ll need to use the GEOID18 interactive tool to get the geoid separation value by plugging in the lat/long and then subtracting it from the ellipsoid height. Here are some simple math equations that represent this:

Height above ellipsoid = Orthometric height + Geoid separation
Orthometric height = Height above ellipsoid – Geoid separation

2.6 STEVE: I had a tough time connecting to a mountpoints for RTK corrections. I did finally get it to work with an IP address, rather than a web address. Can you talk to that? Maybe recommend to the group that they need (if so) the numeric IP address like 161.11.1.10, etc.?

JEAN-YVES LAUTURE (JEAN-YVES): Eos Tools Pro supports both URL Hostnames and IP addresses. A bad URL, one that does not have a valid DNS resolution, can be the cause of not being able to connect to the RTK network. To make sure that your URL/Hostname is valid, simply try it in a browser followed by “:PortNumber” and the source table containing the list of mountpoints should be retrieved from the RTK caster and displayed in your browser. For example: “myRTKNetwork.com:10000”

2.7 CHRISTOPHER: How do you specify a geoid model for collecting elevation data? And where can we find the up to date geoid models?

JEAN-YVES: In Eos Tools Pro there is a list of geoid models available per country. They are up-to-date. These geoid models are supplied by government entities.

2.8 STEVEN: Is there anything to worry about with switching from GEOID12b to the new GEOID18?

JEAN-YVES: There is nothing to worry about unless you are comparing your results with a geodetic benchmark referenced to GEOID12b while switching to GEOID18. GEOID18 is more accurate than GEOID12b, as more measurements were made, thus resulting in a much better geoid model. From the NOAA website presenting GEOID18, you can read more about how they describe this:

NOAA: “GEOID18 is a significant improvement over GEOID12B. This includes improvements to the underlying gravimetric geoid model, increases in the accuracy and distribution of GPSonBM data used to constrain the model to bench marks, as well as significant new data analysis and advancements in modeling techniques.”

2.9 ROBERT: Does using the RTK setup work only if you have a static receiver? For clarification, we use an Arrow GNSS receiver and antenna set up in a backpack configuration.

JEAN-YVES: You can move (i.e., be dynamic) with your rover (your GNSS receiver carried by the field personnel), and every single point (of each second) will be in RTK. You do not need to stand still to have RTK.

2.10 BRIAN: If we’re using an Eos Arrow Gold antenna with an RTK network, how long does it take to get to 1-3 cm accuracy. Also, if we move to another position, how long does it take to regain that same accuracy?

JEAN-YVES: As long as you are receiving your corrections — meaning that you are within an RTK network or close to a base station — and you have a clear view of the sky, then it should take only a couple of seconds at most. Once RTK is achieved, if you move to a different location while keeping the receiver turned on and the antenna facing the sky, then there will be no down time.

2.11 BRIAN: How well does the Eos Arrow Gold retain accuracy under moderate in urban canyons (say buildings under five stories tall) and/or light canopy?

JEAN-YVES: In the case of urban canyons, a five-story building will not be an issue, provided the streets are more or less wide enough for you to view a good part of the sky. In addition, if you are doing RTK, you will also have to ensure that your base station or RTK network supports four GNSS constellations (i.e., GPS, Galileo, GLONASS, BeiDou) rather than fewer (which is common for base stations and RTK networks using older hardware) in order for an optimal number of satellites to be used. The same considerations apply to doing work under light canopy. Moderate canopy can be a problem if you are using RTK; this will depend on just how “moderate” is moderate. In this case, we would recommend using our Eos Laser Mapping^™ for ArcGIS.

2.12 BOGDAN: Is the centimeter-level precision also available for vertical measurements (i.e., ellipsoid height) with the Arrow GNSS receivers?

JEAN-YVES: Your GNSS elevation is usually 1-3 times less accurate than your horizontal accuracy. Ellipsoidal heights are at the foundation of GNSS height measurements; they are stored in the attribute fields immediately upon being received by ArcGIS Field Maps. Meanwhile, the orthometric heights in the point geometry are set in Eos Tools Pro by selecting a geoid model.

2.13 ERIC: I have an Eos Arrow 100 with an external antenna (which I wear on my hat) that has a wire. Is there a way to Bluetooth the antenna to the receiver, rather than use the wire?

JEAN-YVES: The antenna must be connected to the receiver via wire, rather than Bluetooth. What you might do is consider some of our field gear options other than the hat. One option is to mount the receiver, antenna and device on a handheld bracket.

Other options are to use a safety vest with the antenna mounted on the vest’s shoulder pouch, or to mount the antenna on a backpack rangepole. This will make the wire less obvious during your data collection. Please inquire with our team, and a nearby representative will contact you with some options.

2.14 STEVE: When a field team needs to jump in and out of a vehicle, what do you recommend in terms of letting the GNSS receiver reestablish itself with a good lock and position each time? Is there an ideal timing or technique? Should we do anything at the beginning of the day, such as get a good SBAS fix and then move it over to RTK? We’d love any ideas for this workflow.

JEAN-YVES: This depends firstly on your configuration. Since you mentioned RTK, I will assume you’re using an Arrow 200^® or Arrow Gold^®. In all cases, re-acquisition of the GNSS signals with an Arrow GNSS receiver is relatively quick. So, you should be able to simply take your receiver out of the car and, by the time you get to your mapping location, it will be ready with RTK. There is no need to let it work with SBAS at the beginning of your day. If you’d like to ensure zero reacquisition time, the proper way to do this would be one of these workflows:

1. First you could use a quick-connect/disconnect cable adapter on a magnetic mount on your vehicle roof. The same adapter would then also be on your rangepole (this will require a longer cable). In this way, you can keep your antenna outdoors and locked to the sky, and quickly disconnect it from the vehicle roof, reconnect it to your antenna, and you can instantly begin data collection without re-acquisition time.
2. Another less elegant option would be to leave the antenna/receiver outside of the window to maintain its sky visibility.

2.15 MICHAEL: What is the approximate battery time when streaming RTK data?

JEAN-YVES: This depends on the model of Arrow Series® GNSS receiver you are using. The Arrow Gold has about 7.5-8 hours of battery autonomy. The Arrow Gold+^™ has an average of 11 hours of autonomy. To view the approximate battery life of an Arrow receiver when used with a variety of differential correction sources, please select the model of Eos GNSS receiver you are interested in from this list, and scroll to the “Technical Specifications” for that model.

2.16 FADI: Does the Arrow Gold have a tilt compensation?

JEAN-YVES: The Arrow Gold does not feature a tilt compensation.

2.17 JERRY: How could we get PPK working on the Arrow Gold? In our case, we can’t always get a cell connection for RTK.

JEAN-YVES: The Arrow Gold supports post-processed kinematic (PPK) via the Atlas^® differential correction service. It is a paid subscription. Please contact our team to be connected to a nearby representative who can discuss the best option based on your region.

2.18 FABIO: Do you offer any additional training to help our team preconfigure our equipment before we head out to a remote area with no bandwidth or cell-phone connectivity?

JEAN-YVES: Fortunately, no training is required. If you are using an Arrow GNSS receiver for submeter applications, and if a free SBAS is available in your area, then the Arrow receiver will automatically connect to and use the SBAS signals for free submeter positioning.

If no free SBAS is available in your area, then simply choose from these models: Arrow 100+, Arrow Gold Basic, or Arrow Gold+. These three models can be activated worldwide with a 50-centimeter Atlas® subscription satellite service, and it will work effectively the same way for the field user, who simply needs to turn on the device to start receiving these corrections.

If your need for accuracy is higher than submeter, then an Arrow Gold or Arrow Gold+ can be activated worldwide with an Atlas H10 subscription; this will provide about 4-10 cm horizontal accuracy.

2.19 SAMUEL: How much do corrections vary between RTK networks? If one dataset used corrections from a custom RTK base station located onsite, and another dataset comes from an Arrow Gold connected to a CORS station 15 miles away, will there be a discrepancy between the corrections?

JEAN-YVES: As long as the base station coordinates are tied to the same geodetic network, and they are in the same datum as the RTK network, then there should be no discrepancies.

2.20 KATE: If our accuracy requirement is submeter, but we are working in an area with a lot of interference, would you recommend we use point averaging, a higher-end receiver, or something else?

JEAN-YVES: By “interference” I assume you are referring to sky obstructions, caused by either canopy or urban canyon (e.g., high buildings). If this is the case, for the best possible accuracy, we recommend using our free Eos Laser for ArcGIS solution. All you need is your Arrow GNSS receiver, an LTI laser rangefinder (e.g., TruPulse 360B, TruPulse 200X), ArcGIS Field Maps, Eos Tools Pro, and an iOS or Android mobile device. Please refer to this link for more information: https://eos-gnss.com/products/solutions/laser-mapping

2.21 ADAM: Should we use RTK or SBAS with our Arrow 100^® for forestry applications? For context, we mark property lines for harvest areas. We notice the signal is worse under conifer trees vs. deciduous trees. Also, should we use averaging? We mainly paint-mark trees as we walk while watching the screen to see where we are on the property line.

JEAN-YVES: Do not use RTK under heavy canopy. There would be way too much downtime. In addition, it’s not just the type of canopy that affects your accuracy under trees, but mainly the diameter of the trunks and the density of trees. It is important that you have physically mounted the antenna in the best possible location. The ideal setup, for instance, would be the antenna on a backpack rangepole, mounted on a forestry cruising vest at head level; the receiver in a pouch in the vest; and the antenna cable properly secured around the pole. Alternatively, a compromise would be to use a forestry cruising vest with the antenna inserted in a sewn pouch on the shoulder. Please inquire with our team to be put in touch with a representative who can present you with the various options.

3. ArcGIS Field Maps & Mapping Questions

3.1 MULTIPLE: Could you please share the Arcade script Tyler used?

Eos Positioning Systems: Yes! Tyler’s ArcGIS Arcade script is available as written here:

// change to false if feet desired
var useMeters = true;

var geom = Geometry($feature);

if(!IsEmpty(geom)){
  var elevation = geom.Z;
  if (useMeters){
    return elevation;
  }
  else{
    return Round(elevation * 3.2808,3);
  }
}
else {
  return null;
}

3.2 ALEX: Is there a way for coordinates to be collected in UTM format rather than latitude/longitude?

TYLER GAKSTATTER (TYLER): Publish your layer in a UTM coordinate system to capture coordinates in UTM. Regardless of the map setup, the layer will store the data in the coordinate system it was published in.

If you want the map to also operate in UTM, then you will need to upload your own basemap in the UTM coordinate system and use that as the basemap in your web map.

3.3 SHAYNE: So even if we use an Esri basemap in Web Mercator, ArcGIS Field Maps will store the data in the coordinate system defined by the location service or the feature layer?

TYLER: Correct! Publish your layer in the coordinate system of your choosing. Then add it to a web map with the default Esri basemap. Go out and collect some data and download it to ArcMap or ArcGIS Pro. If you look at the layer properties, you’ll see the spatial reference is set to the coordinate system you choose.

3.4 JASON: Does the ArcGIS Field Maps geometry measurements default to geodetic-based measurements or planar? How do you set to ground-based distances?

DOUG MORGENTHALER (DOUG): Typically Field Maps uses geodesic measurements for tools like computing length/area during collection, or measurement using the measure tool. Note that some Arcade functions use planar measurements, so if you’re writing your own expressions be sure to keep an eye out for those.

3.5 JASON: Can you apply a custom coordinate system when creating a feature layer via ArcGIS Online?

TYLER: One solution is to publish a layer (could be a blank layer) in a specific coordinate system using ArcGIS Pro, then use it as a template when creating a new layer in ArcGIS Online.

Add Item → Feature Layer → From Template → Select previously published layer.

3.6 JESSICA: Why would someone want to use a custom basemap? Is it faster or more efficient?

TYLER: There could be a few reasons, including these:

• Avoid a datum transformation.
• View coordinates in a coordinate system other than WGS84 Web Mercator Aux Sphere. The official coordinate system in most states is StatePlane so this is a common choice for users wanting to use that coordinate system with all their maps and data.
• When higher-resolution imagery is sourced somewhere else (e.g., a drone flight)
• When more up-to-date imagery is sourced somewhere else (e.g., a drone flight)

Imagery is faster only if you side-load it or download it for offline use. You can do this with both Esri basemaps and custom basemaps.

3.7 DYLAN: Is there any way to disable the manual point entry in ArcGIS Field Maps to eliminate accidental manual data entry?

DOUG: While we don’t have explicit capabilities to require GPS collection, one could ensure that when the feature service is published as Z-aware, if you do not provide a default Z-value then manual locations cannot be added.

3.8 VINCENT: Are there plans to add custom error messages for form validation in ArcGIS Field Maps? For example if they have formatted some code in a string field incorrectly?

DOUG: We are considering extending smart forms to incorporate additional validation logic. Please email me if you’d like to share specific scenarios you’d be interested in us supporting.

3.9 JOHN: We have had issues with image tiles consuming large amounts of data in ArcGIS Field Maps. Can you address best practices to reduce?

DOUG: There are a couple of ways to limit the size. One is to use predefined offline areas (set up in ArcGIS Field Maps web app or in ArcGIS Online) and create an irregular extent to ensure you get just the areas required. Alternatively, reducing the level of detail can limit the data size in ArcGIS Field Maps, though with some tradeoff in resolution at larger map scales.

3.10 STAN: We need to work offline since our data is sensitive. Is there a way we can start the process online but not upload any complete survey files?

DOUG: I’m not quite sure what you mean by survey files, but if you use ArcGIS Enterprise to host your feature layers (and optionally web maps) you can ensure that these are not publicly available (i.e., they could require you to be behind the firewall to access the layers).

3.11 STEVE: Has the issue with offline needing to reconnect to the physical company network (where the database was hosted) been rectified? We just moved to ArcGIS Field Maps and haven’t tested, but we have to use a secondary collection program when we need to go offline because ArcGIS Collector wouldn’t allow us to reconnect (we’re 6 states away from where the DB is hosted).

DOUG: I’m not aware of any outstanding issues where ArcGIS Field Maps has specific limitations due to distance from the database. Of course, latency issues in the network could have a negative impact on the overall experience and responsiveness of both online and offline workflows. You could consider setting up multiple organizations and use collaboration to periodically synchronize between them rather than having each mobile device access the remote (distance-wise) database/portal directly.

3.12 AUSTIN: Will there ever be the ability to have a self-prompted data field within an attribute in smart forms? Basically you record a field within an attribute, and a replicate field pops up until you record some null option. At this time, it’s my understanding that you have to create singular data fields, and that makes it difficult when you collect bulk samples.

DOUG: If these are multiple “samples” then yes this is something we are considering for ArcGIS Field Maps. I’d appreciate if you can share specific examples with me.

3.13 ELAINE: Is ArcGIS Field Maps useful in Urban Forestry, Wilderness Forestry and Natural Resources?

JEAN-YVES: Yes. Please browse our case studies to see how others have been using ArcGIS Field Maps (and formerly Collector) for these applications by browsing our Eos success stories and filtering by industry. You may use the industry filters for natural resources. For Urban Forestry please refer to these:

• Halifax Students Identify $270,000 of Covered Tree Replacements
• Canada Students Determine the Health of 2,000 Street Trees
• Montreal Increases Pesticide Treatment by 6300% Annually

3.14 CHRIS: For Doug, does Esri plan on developing their own webhook process within ArcGIS Field Maps that doesn’t require a third-party license/setup?

DOUG: ArcGIS feature services support utilizing webhooks directly, as well as through popular automation platforms such as Make.

3.15 JOSHUA: Can you migrate an ArcGIS Survey123 survey to ArcGIS Field Maps?

DOUG: Not directly. ArcGIS Field Maps and ArcGIS Survey123 do not have direct/equivalent support. However, many common capabilities such as conditional logic and presentation options are available in both ArcGIS Field Maps and ArcGIS Survey123.

3.16 ED: I would like to be able to select multiple values from a domain list in ArcGIS Field Maps.

DOUG: Thanks for the feedback; we have this on our mid-term road map.

3.17 INGRID: Is ArcGIS Field Maps able to be spatially aware? For example, could you record a point feature and populate an attribute (such as “County”) if it is within a polygon layer that is in the map?

DOUG: Yes, this can be accomplished through the use of calculated expressions within your form. Note that if working offline, the feature layer you’d be querying would need to be included in the map.

3.18 DUANE: Is there a recourse you can point me to to show how you configured the accuracy slider control in the dashboard? That was cool. I’ve been using color shading to show the various accuracies.

DOUG: I’m not certain we have a course available that highlights that aspect specifically, but this topic outlines how to configure selectors which is the dashboard capability I used:

3.19 KANTHEEPAN: What is the difference between ArcMap, ArcGIS Field Maps, and ArcGIS Pro?

DOUG: ArcMap is our legacy desktop product. Several years ago it was replaced via ArcGIS Pro, which continues to deliver new capabilities and is built on a modern software stack and architecture. If you’re just getting started, I’d strongly recommend using ArcGIS Pro. If you’re looking to migrate, here’s a learn lesson to get you started.

3.20 CHRISTOPHER: Does ArcGIS Survey123 support high-accuracy GNSS?

DOUG: Yes, ArcGIS Survey123 does support GNSS receivers, including the Arrow.

3.21 FRANK: If you use the navigation tools in ArcGIS Field Maps, does it consume credits?

DOUG: No. If you are using tools like search (such as for addresses) or compass navigation, credits are not used.

4. Datum Questions

4.1 RICH: What is the difference between WGS 1984 Web Mercator and WGS 1984 Web Mercator Auxiliary Sphere? Why does SBAS use this basemap and RTK the other?

TYLER: I’m not sure of the specific technical differences between them. I don’t think they are much different. From what I’ve gathered, the auxiliary sphere version is optimized for the delivery of basemaps over the internet. Google originally set the precedence of using this coordinate system and everyone else followed suit.

4.2 JASON, JIM: Is there accuracy loss through ArcGIS Field Maps GNSS → Location profile → Web Map → Feature Layer transformations? Are the datum transformations exact? For example, are the coordinates from the receiver identical to coordinates stored in layer, or is there loss of accuracy?

TYLER: There is always a loss of accuracy when implementing a datum transformation. Some transformations are better than others. The common NAD 1983 (2011) → WGS 1984 shift in Field Maps has very little error. Probably in the millimeter range for most areas. Not something to be concerned about for most applications. Datum transformations can be avoided by using a basemap and layer that are in the same datum as the GNSS receiver.

DOUG: In some cases, there might be a scenario where a transformation might be applied in the location profile, and then back to the feature layer. If the location profile is NAD 1983 (2011) → Web Mercator, and the coordinate system of the feature layer is NAD 1983 (2011) this effectively inverses the transformation, so there is no loss of accuracy. To understand the impact of a transformation on accuracy, see this table.

4.3 STEVE: I’m assuming there is not much difference between ITRF 2008 and 2014? ArcGIS Collector is only showing 2008 as a choice, though the speakers mentioned 2014 for SBAS.

JEAN-YVES: Sometimes, it is less than a centimeter in the revisions/adjustments the ITRS makes. What is important is the epoch (for the velocities of the tectonic plate movements). For example, a set of coordinates expressed in ITRF 2008 and ITRF 2014, for the same epoch of 2022, might show a few millimeter difference. But if your tectonic plate moves, for example, 2 cm per year in a certain direction, then a difference between and ITRF XXXX at epoch 2010 and the same ITRF XXXX at epoch 2022 is 12 years of tectonic plate movements, at a rate of 2 cm per year, which equals 24 cm. Therefore the epoch is much more important than the revision of the ITRF core adjustments.

4.4 MIKE, JESSE: What’s the best RTK workflow for connecting to CRTN in 2017.5 epoch? Do I need to use Eos Tools Pro to set any transforms? Or did Esri make any recent changes to ArcGIS Field Maps to enable a 2017.5 transform within ArcGIS Field Maps? Are there any vertical datum 2022 updates?

JEAN-YVES: I am not sure that Esri has added support for NAD83 CSRS 2017.5 yet. In the meantime, the simplest is to use the datum shift feature of Eos Tools Pro to enter a constant XYZ shift in the coordinates.

To further explain, in your case, you want to “fool the system.” You will do your location profile in ArcGIS Field Maps for NAD83 to Web Mercator, but in Eos Tools Pro, you will “shift” the received GNSS coordinates FROM NAD83 CSRS 2017.5 (epoch 2017.5) TO NAD83 2011 (epoch 2010). You may use HTDP to get your set of coordinates (use 0 for the input elevation) and set the from/to values in Eos Tools Pro datum shift menu to compute your shift values. This will do the trick.

4.5 STEVE: We have talked with Eos already about Esri orthophotos not being so accurate that you might see shifting of your centimeter locations not visually aligning in ArcGIS Collector or ArcGIS Field Maps. Could it be worse in different areas of the country where orthos might be better or worse georeferenced?

JEAN-YVES: I think this is related to a datum issue. One must know the datum in which each of the maps components (e.g., basemaps, orthophotos, vector layers, GNSS differential correction source) are. All of these must be in the same datum. Once these datum are known, then the location profile can be set to handle the required transformation from the GNSS receiver to ArcGIS Field Maps.

4.6 SCOTT: It is my understanding that, regardless of which coordinate system the GNSS device is capturing data in (e.g., ITRF2014, NAD83 2011), the data collected in the field will be written to the feature layer in the coordinate system used by the feature layer. In the event that a transformation is required here, how is the appropriate transformation selected? Is this all done automatically? How do we know the transformation selected by the software is appropriate?

TYLER: Scott, there are up to two datum transformations being performed on the coordinate before it is stored. You have control over the “GNSS → map” transformation via the location profile. You have no control over the “map → layer” transformation. Esri software knows the datum / coordinate system of both the map and the layer, so it can pick the best transformation for your area. It doesn’t know what datum your GNSS receiver is using. That’s why the location profile isn’t automatic. Also note that, regardless of the location profile you set, the original coordinates coming directly from the Arrow GNSS receiver are stored in the ESRIGNSS attributes.

4.7 KATE: How do you control the transformation method to convert the ITRF coordinates to NAD83?

TYLER: The third parameter of the location profile is the datum transformation. ArcGIS Field Maps will recommend the best transformation for your location; however, you can select any one of the available transformations.

4.8 CLINT: Is the Eos Arrow system truly collecting natively in ITRF2014 or NAD83 (2011)? We ran into this issue with our older LEGACY GNSS RECEIVERS. No matter what we set the system up to do, it was actually collecting in WGS84 and performing the transformation itself. I just want to be sure that the system is actually collecting natively in those coordinates.

JEAN-YVES: A long story short: The coordinates you get from an Arrow GNSS receiver always follow the datum of the source of the differential correction used. For example, if you are using SBAS (e.g., WAAS in the Americas, EGNOS in Europe) as your source of differential correction, then the Arrow GNSS receiver will output positions in ITRF 2014, epoch 2022.5. If the same Arrow receiver is connected to an RTK network (assume we are in the United States) then the output coordinates will be in NAD83 2011. Unless you configure and activate a datum shift in Eos Tools Pro, the Arrow itself does not do on-the-fly datum transformations.

4.9 CHRISTOPHER: Is there a benefit to keeping the workflow in the same coordinate reference system versus working in a combination of WGS and NAD83 (2011) state plane?

DOUG: Using a common coordinate system allows you to maintain the spatial accuracy from your GNSS receiver. However, in some cases this is acceptable given the project requirements and relative ease of using hosted basemaps such as Esri’s which are in Web Mercator. The most important aspect here is to minimize datum transformations when possible, and to understand the impact of the transformations you do use on the final product.

4.10 CHRIS: There is a valve layer in ArcGIS Online which is used to capture valves during our water main replacements. This is the only layer that is not in WGS 1984 Web Mercator. When we pull it in through portal from ArcGIS Online into ArcGIS Pro, it says source coordinate system / plane system is State Plane 5/NAD 83, and it re-projects it to WGS 1984 Web Mercator — which all other data is in and web map is in. We usually re-project all the data to State Plane 5 when everything is complete and constructed, and lines are built out. Are you saying this shouldn’t affect anything in terms of accuracy and precision? I just want to confirm; when we spoke to Esri they couldn’t figure out how the creator had gotten this into ArcGIS Online without it being in the required default Web Mercator 1984. The GPS points we capture for the water-main replacements are used by civil engineers to redline as-built records, so it’s important for us to confirm this won’t have an impact. In case helpful, WGS 1984 WMAS is what we use in our settings.

TYLER: It should not affect accuracy in any significant way. Maybe a few millimeters. It’s certainly odd that the one layer ended up in a different coordinate system than the others but I would not fret over the accuracy.

Advanced Workflow & Miscellaneous Questions

5.1 XIUXIA: How does Esri Indoor Positioning support work? Is satellite signal involved in this positioning support? How is indoor positioning collected?

DOUG: Indoor positioning in ArcGIS Field Maps uses a registered set of beacons that allow for triangulation of your position.

5.2 SHANNON: Do you have any documentation about how one goes about setting up a profile for distribution for some of the common MDM systems?

JEAN-YVES: For the Eos MDM, please send an email to support requesting the MDM implementation document.

DOUG: For ArcGIS Field Maps, we document the necessary parameters available for use by your MDM.

5.3 BRIAN, BILL: Could you use this technology to perform laser offsets? Specifically, could you connect an LTI TruPulse 360B to ArcGIS Field Maps and Arrow GNSS for a seamless, point-and-shoot workflow to collect remote asset positions?

JEAN-YVES: Yes. Please refer to our free Eos Laser Mapping for ArcGIS. You may also request last year’s laser workshop recording.

5.4 JOE: Do you have any advice for taking elevation into concern when using a laser to capture a point with a prism placed on it? We’ve been deducting the height of prism via post processing. Is that the correct/accurate workflow?

TYLER: That is correct. This would be the best option.

5.5 ANTONIO: What will be the new capabilities with a laser rangefinder (i.e., offsets) in the future ArcGIS Field Maps developments?

DOUG: We do have additional support for laser rangefinders in our mid-term road map. This might include direct integration with some laser rangefinders, but is not intended to completely replace the solution with partners like Eos.

TYLER: Laser mapping is available today using ArcGIS Field Maps with an Arrow and a compatible laser rangefinder.