Setting up a map for Trimble DA2 Catalyst survey in different coordinate system

[NicholasKehler]

I cannot figure this out...

I purchased a Trimble DA2 Catalyst and I'm planning to survey with this equipment using Field Maps. I understand how ArcGIS Online maps are using the basemap to set the spatial reference, but I cannot figure out how to get an online map into my choosen spatial reference.

I want to survey in NAD 1983 (CSRS) v7. It doesn't seem like there is a transformation from this to WGS1984 when I try to setup my profile in Field Maps. I believe I understand that the best scenario is to not even need to do a transformation. So with that, I want to create an ArcGIS Online map that is using NAD 1983 (CSRS) v7 as the spatial reference. I am at my whits end, so please be very specific in your instructions, I'm far from an expert ESRI user. Thank you so much in advance.

[NicholasKehler]

Hi. Here is the procedure I've written down for myself and what has been working for me.

1. First I've setup a dedicated project with ArcGIS Pro and I've set the spatial reference to "WGS 1984 Web Mercator (auxiliary sphere)". You might not need to start in ArcGIS Pro, but that's where I do the majority of my work and it's where I'm most comfortable. We use this spatial reference because it is the same as the ESRI Basemaps. Web maps need to have files that are in the same spatial reference as the basemap to work. Apparently you can create your own basemaps in the spatial reference of your choice, but since I'm covering a wide geography, it's not worth the ESRI Online space.

2. Then I create a shapefile that is my survey file. This is a project specific file, so I've created a blank file and I simply export a copy of it for each new project. This shapefile needs to have Z values enabled when you create it. You should tailor this to what you're doing, so if you can put in some work at the front end, your surveying will be easier in the field. In my survey shapefile I've created fields for "CODE", "DESCRIPTION", "X", "Y", and "Z". You also want to run "Add GPS Metadata Fields", which will add a bunch of fields to your shapefile as well. This is nice to see the information that is coming from your DA2. That information includes the LAT and LON coordinates and the altitude (ellipsoidal height). 

3. Within the "CODE" field I've setup a domain. This domain contains all of the survey codes that I'm planning to use when I'm collecting data. This way I don't need type in a code or reference a sheet in my pocket. It's simply one of the fields that shows up when I create a point in Field Maps and I can select from a drop down list. 

4. Now I share this survey file to my ArcGIS Online. A couple of things to remember. Within the Map Properties, you should have "Allow assignment of unique numeric IDs for sharing web layers" enabled. Then when you run the "Share as a web layer" tool, you need to click on "Configuration" and the edit pencil beside the layer. Then select "Enable editing and allow editors to..." and also select "Enable Sync". This will allow you to add points to the layer from Field Maps, and also to setup offline maps. 

5. Now I have a hosted web layer in my ArcGIS Online. Then I create a web map and add that one hosted web layer to it. I try not to add more than one editable layer at a time because you'll need to select which layer you're editing for each point you create. That's an extra click every time and a waste of time. The web map will be in the same "WGS 1984 Web Mercator (auxiliary sphere)" spatial reference, which is good. Save this map as whatever. I've been using one map and just switching out my hosted web layers, but you could easily create a web map for each project.

6. Since I also work in more remote areas, I've found it is important to work offline. If you're not offline, then each point gets syned with ArcGIS Online every time you save it. Unless you're in a very good internet service location, that's less than great. I always try to work offline. To do this, you need to change some settings in the web map in ArcGIS Online. Go to your Content, click on the web map file you saved, click on Settings, and setup the offline settings. You'll want to get it so Offline Enabled is checked, and then also setup an offline map area. Download the map area on your mobile devide before heading out to the field.

7. The web map is now in Field Maps and it's ready to go. Setting up the DA2 in Trimble Mobile Manager is the next priority. In the Configuration page, you want the GNSS correction source to be on "Auto". This allows the DA2 to change between the various correction source based on your connection or location. In the Output setting you want to "Select from list" and then pick the spatial reference you ultimately want to work in. Honestly, I'm not 100% sure when it's doing with this setting, but you should properly select it one way or another. Maybe it's important if you're using something other than Field Maps. Finally, in the Geoid setting you want to pick the geoid you're working with. This is important because the z value of the point in your shapefile will be based on this going. If you select the wrong geoid, you'll have to do some post processing to translate your altitude (ellipsoidal height) to orthmotric height. Get this setting right the first time.

8. Now you just collect a bunch of points. When you create a point in Field Maps you'll select the survey code from the domain list you created. You can add a description if necessary, and you'll also see the "X", "Y", and "Z" fields, but they won't be populated. Don't worry about that for now because we'll populate those after the survey is done.

9. After the survey is done, I bring the shapefile back to my desktop and load it up in ArcGIS Pro. All of the points I collected are in there and all of the GPS metadata is populated. I then run a "Calculate Geometry" to populate the "X", "Y", and "Z" fields. Remember that the "Altitude" field within the GPS metadata is the Ellipsoidal Height. The elevation that is captured within the Z value of the shapefile is the Orthometric Height (based on the geoid). When you calculate the geometry you also want to pick the correct spatial reference. The location of each point in the shape is output as LAT and LON from the DA2, we're not turning that into a project coordinate.

That's it. That's my procedue and it's what has been working for me. I've done a few surveys now and they went very well. I'm honestly thrilled with my DA2 purchase. The cost for the subscription service does seem expensive, but when you compare against the number of hours I'll be using this, it is still the most cost effective solution for me. I hope this helps you get a little further along.