Accuracy

Important information about the metric and WGS84 latitude and longitude returned by Dragonfly

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The metric and WGS84 coordinates returned by the Dragonfly App and shown inside:

  • the Dragonfly Web User Interface.
  • the Dragonfly API Status call.
  • the local CSV files.
  • the MAP page of the Dragonfly Cloud Dashboard.

…are a function of:

  • the availability (or not) of a well scaled and positioned floor plan image.
  • the geo-referencing method used (floor plan image VS DWG).
  • the WGS84 origin of the coordinate system (provided to the Dragonfly engine when the positioned is started).
How to make sure that the information you are looking is fresh
Please be aware that an hard refresh of the Dragonfly Web User Interface and/or a restart of the Dragonfly App and/or the removal of the “jsmeta” folder of the Dragonfly App, might be needed in order to see updated info about the coordinates!
Floor plan imageGeo-referencing done byPositioning engine started byMetric coordinatesWGS84 coordinatesDOT inside Dragonfly Web User Interface and Dragonfly Cloud Dashboard
Not uploadedBy providing the DWG metric coordinates using: pressing the ▶ button inside the Dragonfly Web User Interface

"Do not use floor plan image center as origin" - UNMARKED or MARKED in the View tab
X,Y distance in meters from the 0,0 origin shown in the DWG

HIGHEST ACCURACY! 		Not meaningfulNot shown
calling the Dragonfly Start positioning API and providing, as origin of the metric coordinates system:
  • nothing
  • an empty array -> []
  • an array with 0 -> [0,0,0,0,0]
Uploaded, scaled and overlaid on top of your venue using the Dragonfly Cloud Dashboard By providing the DWG metric coordinates of the reference points using: pressing the ▶ button inside the Dragonfly Web User Interface

"Do not use floor plan image center as origin" - MARKED in the View tab
X,Y distance in meters from the 0,0 origin shown in the DWG

HIGHEST ACCURACY! 		Not meaningfulNot meaningful
calling the Dragonfly Start positioning API and providing, as origin of the metric coordinates system:
  • nothing
  • an empty array -> []
  • an array with 0 -> [0,0,0,0,0]
pressing the ▶ button inside the Dragonfly Web User Interface

"Do not use floor plan image center as origin" - UNMARKED in the View tab		X,Y distance in meters from the WGS84 coordinate of the center of a north aligned version of your floorplan

Not accurate - because very likely the WGS84 coordinate of the center of your floorplan is far away from the WGS84 coordinate 0,0
Uploaded, scaled and overlaid on top of your venue using the Dragonfly Cloud Dashboard By pinpointing the reference points on the floor plan image shown inside the Dragonfly Web User Interfacepressing the ▶ button inside the Dragonfly Web User Interface

"Do not use floor plan image center as origin" - UNMARKED in the View tab

X,Y distance in meters from the WGS84 coordinates of the center of a north aligned version of your floorplan *

GOOD ACCURACY
Real WGS84 coordinates * Shown over the floorplan image
calling the Dragonfly Start positioning API and providing, as origin of the metric coordinates system, the WGS84 coordinates of the center of your floorplan + the rotation **
calling the Dragonfly Start positioning API and providing, as origin of the metric coordinates system, a WGS84 coordinate chosen on the floor plan of your venue ***X,Y distance in meters from the chosen WGS84 coordinate *

GOOD ACCURACY
pressing the ▶ button inside the Dragonfly Web User Interface

"Do not use floor plan image center as origin" - MARKED in the View tab		X,Y distance in meters from WGS84 coordinate 0,0

Not accurate - because very likely the WGS84 coordinate of the center of your floorplan is far away from the WGS84 coordinate 0,0

* The accuracy is directly related to the quality of the floorplan scaling and overlaying processes, and to the quality of the geo-referencing process.

** The WGS84 coordinates of the center of your floorplan + the rotation, can be found inside the KML file that ends with “_o.kml” that be downloaded using this API call.

*** You can get the WGS84 coordinate of a chosen point on the floor plan of your venue with these easy steps:

  1. Open the Dragonfly Cloud Dashboard.
  2. Select General from the top menu. Then select Floorplans.
  3. Click on the floor plan of interest (not on the EDIT button!).
  4. Zoom in as much as possible to the point of interest over the floor plan image and click on it.
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