Geolocation common issues

Geolocating a PVcase project in AutoCAD is typically best done using the Import terrain tool in PVcase Ground Mount or the Import KML/Import Prospect Data features. These tools use the UTM (Universal Transverse Mercator) coordinate system and place the project origin at the center of the selected UTM zone. This approach follows common geolocation conventions and helps ensure consistent alignment across GIS/CAD workflows. Tools such as AutoCAD Map 3D and Civil 3D use a similar methodology.

However, geolocation presents complexities. Occasionally, you might need to work in a different coordinate system, such as NAD83. Discrepancies may also occur when importing third-party files (for example, a background map, survey, or civil drawings that were created using a different datum, projection, or units).

This article addresses common PVcase geolocation issues in AutoCAD, such as coordinate system mismatches, map offsets, rotation between the grid and true north, and alignment problems with third-party CAD/GIS data, offering practical guidance for diagnosis and resolution.

Importing a KML or Prospect Data

When importing a KML or Prospect Data file into a project, we can choose either to retain the project's existing geolocation or use the geolocation from the imported file. The PVcase import functionality uses the UTM (Universal Transverse Mercator) coordinate system for geolocation. This places the project’s origin at the center of the selected UTM zone.

If your .dwg was already georeferenced differently from how PVcase uses it, the imported data might misalign with the background map. 

You may resolve this by clicking No in the pop-up message shown in the screenshot below, which appears just after choosing the file to be imported. This way, the objects in the imported file will align with the existing geolocation of the .dwg.

If your project is not geolocated, or was geolocated via the Import terrain tool in Ground Mount, you can choose Yes in the pop-up window, and the imported objects will match the background map.

Changing the coordinate system of a project

By default, the Import terrain tool of Ground Mount uses the UTM (Universal Transverse Mercator) coordinate system, but you might need to switch to a different coordinate system.

With Civil 3D, or Map 3D, you can make use of the MAPCSASSIGN and GEOCSASSIGN commands for this purpose. However, if you are using the standard version of AutoCAD, these commands are unavailable, and you will need to use the GEOGRAPHICLOCATION command. Please keep in mind that this command lets the user specify the geolocation's origin, which may not align with common geolocation conventions. Nevertheless, the following method, also demonstrated in the video below, will allow you to match your existing layout or parcel boundaries to the background map, while switching to a new coordinate system:

1. Find a point in your .dwg file that will be used as a reference, and can be visually identified in a satellite view. For example, a tree, the corner of a parcel, or a building.
2. Open the geolocation menu of AutoCAD by typing GEOGRAPHICLOCATION in the command line and pressing ENTER, or going to the Insert tab of AutoCAD and using Set location.

3. In the search bar of the Geolocation window, enter the coordinates of your project (Latitude and Longitude). 

   

4. Place the marker in the reference point used in step 1 by right-clicking on the map and choosing Move marker here. Click on Next.

5. Select the new GIS coordinate system that you want to use. Click Next.

   

6. Back in the workspace of AutoCAD, select the reference point chosen in step 1 and press ENTER. Define the North direction as a straight orthogonal line upwards, and press ENTER. 

   

Depending on your previous geolocation settings, performing this action might alter the reference point used to define grid north direction. This can result in a slight rotation of the background map, which can be corrected by following the steps in the next section of this article.

The background map is slightly rotated

If the map is slightly rotated with respect to your layout or parcel boundaries, you have two options:

Option I: Rotate your AutoCAD objects (ROTATE command)

This option is valid only if you have not yet generated a PVcase layout. If you already have one, please do not rotate it manually, as this will likely affect the object's properties and corrupt the project's information. Instead, please rotate your parcel boundaries, then regenerate your layout with the adjusted azimuth. Alternatively, use the GEOGRAPHICLOCATION as described in the following paragraphs.

Option II: Rotate the map (GEO command) 

Use the GEOGRAPHICLOCATION tool from AutoCAD to define a new north direction and rotate the background map. To do so, please apply the following steps, also shown in the video below:

1. Select a reference point that should match in the map and layout, but does not because of the rotation. For example, a tree, the corner of a parcel, or a building.

2. Measure the rotation of the map by, for example, drawing two straight lines from the geolocation origin (red pin) to the reference points chosen in the previous step, and measuring the difference using the MEASUREGEOM command in AutoCAD.

   

3. Draw two lines from the origin of geolocation (red pin). One with the current north direction, and another one with the rotation angle measured in the previous step.

   

4. Open the Geographic Location menu in AutoCAD by typing GEOGRAPHICLOCATION in the command line and pressing ENTER, or by going to the Insert tab and using Set Location. Keep all settings as they are in your project until you reach the last step, where you have to define the north direction.

   

5. Back in the workspace, define the new north direction by re-drawing the line drawn in the previous step, where the rotation angle was applied.

The background map does not match the layout or parcel boundaries

If the reason it is not matching is a slight map rotation, please follow the same procedure described and shown in the previous section of this article, titled "The background map is slightly rotated."

However, if your layout or parcel boundaries are completely off the map in the background, please follow the same procedure described and shown in the second section of this article, titled "Changing the coordinate system of a project." 

How to locate your project's geographical coordinates (Latitude and Longitude)

If your coordinates tab is not visible, please make sure to enable Coordinates in the Customization menu in AutoCAD.

Once enabled, you will find them in the Status Bar, as shown in the screenshot below. They will update continuously, showing the coordinates of the location under your mouse cursor. The displayed coordinates may vary based on the user's needs. You can switch between coordinate types at any time by right-clicking the numbers and selecting the new coordinate type to display:

The geographical coordinates do not match the coordinates of AutoCAD

Understanding the difference between Geographical and Absolute coordinates is crucial since these coordinate types are independent, and confusing them may lead to errors.

Geographical coordinates

They refer to the Latitude and Longitude based on the geolocation of your project. To locate this information in the standard AutoCAD version, look at the Drawing coordinates tab in the Status Bar, as illustrated in the screenshot below. 

They will update continuously, showing the coordinates of the location under your mouse cursor. If you do not see this tab, please check the previous section of this article. To ensure that geographic, rather than absolute, coordinates are shown, right-click it and confirm that Geographic is selected:

Absolute coordinates

The Absolute coordinates, on the other hand, are calculated in the units selected by the user and depend exclusively on the current User Coordinate System, which the user can modify at any time using the UCS command. These are the coordinates that PVcase exports in the Bill of Materials. To find them, you have two options:

1. Selecting the object and checking its Properties:

2. Move the mouse cursor over the object's location, then check the Coordinates tab in AutoCAD, ensuring that Absolute is selected. If you do not see this tab, please refer to the previous section of this article on how to display coordinates:

True North and Grid North

Representing the Earth's 3D spherical geometry on a 2D AutoCAD plane requires a map projection, which inherently introduces distortions. Consequently, the divergence between True North and Grid North arises from the mathematical challenge of flattening a curved surface.

• True North is the direction along the Earth's surface toward the geographic North Pole (the axis around which the Earth rotates).
• Grid North is the "upward" direction of the vertical grid lines in a specific map projection. Because these grid lines are drawn perfectly parallel to one another to facilitate easy 2D drafting and calculations, they do not converge.

When your project sits exactly on the central meridian of the projected map in AutoCAD, the Grid and True North align. As you move away from this center, a "convergence angle" develops, causing a few-degree azimuth offset. While PVcase’s azimuth considers only the AutoCAD project’s Grid North, you can adjust this and align your frames to True North in a geolocated project by following these steps:

1. Using the Lat-Long markers from the Geolocation tab, place two points with the same Longitude, but separated by a small Latitude.

2. Draw a line from Point 1 to Point 2. This line represents True North.
3. Draw a line from Point 1 in the AutoCAD north direction. This line represents Grid North.
4. Measure the angle between the two lines.

5. Adjust the Azimuth in the Park settings accordingly, and your layout will now be generated according to True North.

Working with NAD83 and Feet

Working with the NAD83 (North American Datum of 1983) coordinate system, the standard in North America, typically involves using feet as the unit of measure. Since most projects require delivery in feet, the following workflow is broadly applicable:

1. Make sure that the PVcase and AutoCAD units are set to Feet before any other work is performed. Otherwise, the map and any associated line work will not geographically align, and the scale will be incorrect. You can do this adjustment in the Layout generation settings menu, as shown in the following screenshot:

2. Geolocate the project using the NAD83 coordinate system. In this case, avoid using the Import terrain tool, as it defaults to UTM and is not recommended for this workflow.
3. Once you have done this, if the project's site data is imported from PVcase Prospect, you should click No in the pop-up message shown in the screenshot below, which appears immediately after selecting the file to import. This way, the objects in the imported file will adapt their positions to the current coordinate system (NAD83) and will not be overwritten by UTM, which is the default coordinate system of the imported file.