Setting up Drawing's Georeference

 

Specifying a Coordinate System

Plex.Earth offers the ability to import imagery and terrain into AutoCAD drawings, as well as the capability to publish 2D and 3D designs to Google Earth. Georeferencing, i.e. the process of adding geographic information to the drawings, is mandatory in order for the software to know where to place the images or the elevation data when these are imported. Similarly, designs should be in the correct X-Y coordinates in AutoCAD, so as when exported to Google Earth, to be positioned in the right area.

Adjusting the georeference settings of a drawing with Plex.Earth, can be done very easily, by clicking on the Georeference icon, in the "Project" panel.

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In the window that pops up, two options are displayed:

  • Specify a Coordinate System
  • Specify its Location

In the following steps, all the necessary information is provided for defining the coordinate system of a drawing, for both options. As georeferencing is mandatory in order to use Plex.Earth 4, this is the first thing that must be done, before using any of the other software’s features.

Specify a Coordinate System

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In most engineering projects, whether we start a drawing from scratch or work in an existing design, the coordinate system is usually specified and known. In this case, all that has to be done is to select it from Plex.Earth’s dropdown lists.

Note that Plex.Earth supports over 3,000 coordinate systems worldwide. In the rare case where a system is not included in the list, contact us at support@plexscape.com, with its definition or EPSG code and we will add it for you.

The exact procedure is as follows:

1. Click on "Select from list" at the "Specify a Coordinate System" option.
2. Define "Country or Region", "Coordinate System" and "Units".
3. Click on "Select".
4. Click "OK" in the first window.

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The drawing is now georeferenced.

If you do not know which coordinate systems apply to your project’s site, you can go to your area of interest in Google Earth and keep the following details.

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Then, go back to Plex.Earth and this time set "Earth" as "Country or Region" and select your respective "UTM Zone" as a coordinate system.

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This workaround is suggested to be used only in new, blank drawings. If there is already a design in AutoCAD, drawn into unknown X-Y coordinates, then most probably georeferencing this way, would lead to import mistakes and inaccurate exports. In this case, the "Specify its Location" option should be used.

Specify its Location

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The previous method can be applied only when the coordinate system is known or when we just started designing. However, there are cases where an existing drawing has been designed without taking into consideration any georeference system or where the georeference system is unknown to us. What can be done then, is to associate a point in AutoCAD to a point in Google Earth. This way, Plex.Earth will automatically georeference our design.

The steps for this option are the following:

1. Click on "Specify on the map" in the "Project Georeference" window.

2. Manually zoom in to your area of interest in the displayed map and place the marker to define a reference point.

If you do know the Lat, Lon coordinates of this point, set them in the "Geographic box" and click "Go", to set the marker in this exact point.

If you already have your area open in Google Earth, click "Sync map to Google Earth view", to quickly get there with no browsing.

Use the "Re-center marker" in case you move to an area where you cannot see your marker.

Click "Next".

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3. Now, associate this reference point with a specific point in your drawing, either by providing its X-Y AutoCAD coordinates (Point X,Y) or by picking manually its position in the drawing.

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It may be also necessary to alter the angle of the drawing considering the north direction.

Again, define your units.

4) Click "FINISH" and "OK" in the first window.

The drawing is now georeferenced.

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Warning: Never have "Specify its Location" and "Specify a Coordinate System" both selected. This will probably result in Plex.Earth to use the wrong option from the one you want. Just keep only one of these two options active and click to remove the other one.

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Many drawings are georeferenced with AutoCad or with other verticals, like Civil 3D, by using the "GEO" command. If you get notified that your drawing is already georeferenced, you can always keep this option and you do not have to define it again with Plex.Earth. Alternatively,  just click on "USE PROJECT GEOREFERENCE INSTEAD", in order to get back to Plex.Earth's georeference menu.

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Conclusion

Now that your drawing is georeferenced you can start your design journey. You will quickly notice that Plex.Earth is a great companion. Just take a look at our next tutorials and get ready to import satellite imagery or terrains, literally in a few minutes. Finally, also don’t forget that "seeing is believing", so just go ahead and publish your drawings into Google Earth and create drone-like presentations for your designs. Things with Plex.Earth are always that easy and with a great impact on your productivity.

Feel free to contact us at support@plexscape.com, for any questions you may have and don’t forget to start your free trial today.

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