Reach RS and XYZ coordinate question

I’m a new Reach RS user, new to GPS measurement, and am really happy with my experience so far. Our application is to use the Reach RS equipment (one rover, one base station) to measure ground control points for use in our aerial drone mapping. We use Pix4d to process the GCPs and drone imagery and I am comfortable and confident in that workflow.

The Survey capability of the Reachview app allows for three file export types and the ESRI_Shapefile is the best for my Pix4d application. The DXF option interests me as well, but I might be confused about the outputs. It appears as though the data exported in the DXF for the points measured in Survey are in the form (latitude, longitude, elevation). I was expecting (X, Y, Z), which is the standard format for DXF and what my drawing program (Rhino3d) expects. Clearly a conversion must occur in order to go from GPS (lat, long, elev) to Cartesian (X,Y,Z). If someone can point me to a workflow that will handle this conversion easily I would appreciate it.

Also, in my wishlist for the upcoming releases of Reachview Survey would be inclusion of this conversion along with a user entered choice of defining the origin as either the base station or one of the measured points. If this capability could be added, then I would also appreciate being able to export in metric or imperial units. I look forward to your responses. Thanks for any help you can provide.

Jon Balasa
Collision Engineering Associates, Inc.

Thanks for feedback. The latest “dev” versions also contain two kinds of CSV formats. Soon these will make their way to the “stable” releases as well.

I am not sure I follow, could you please rephrase this?


Thanks very much for the response. For our application we are usually concerned about relatively small areas (under 1 mile) and are primarily concerned about relative accuracy between the measured points, not accuracy relative to the nearest survey datum. Therefore, our main priority is accuracy within our project area. The conversion I mentioned is simply going from the GPS lat, long, altitude to Cartesian XYZ. After doing some research I can see that that conversion is more complicated that a simple mathematical formula, so I can understand if that will not be functionality in the Reachview software.

I was able to find a workaround within Pix4d to get XYZ positions for my ground control points (GCPs) measured with the Reach RS system. Once you import a minimum 3 GPS referenced photos you can import the GPS data collected with the Survey application in Reachview. When you click on the GCP in the viewer, in the properties of the point, Pix4d displays the XYZ position for the point, calculated based on the GPS system that the user referenced. Those coordinates can then be exported to a spreadsheet for additional manipulation or a drawing program.

If you were to implement a way for a user to export XYZ data, it would be valuable to me and maybe others to establish an origin within our project area rather than some survey datum miles or kilometers away. For example, I measured an area yesterday and the first point I measured was located at 430037.244m, 3704069.725m, 374.108m. Since I am only concerned about relative distances between the points that I measured, I subtracted these values from the XYZ values of the other points I measured, essentially creating a new local coordinate system. Then, I would ask that one of the export options would be a DXF file but with XYZ positions for the measured points in the new local coordinate system.

It would be nice if the software could process this transformation rather than for me to do the additional transformation in post-processing. This is not a criticism of the software and the tool your team has developed. This is just a wish list item as you add more functionality as you make your product better and potentially market to different users.

Thanks again for the response. I look forward to the next updates to the software.

Jon Balasa

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