> For the complete documentation index, see [llms.txt](https://docs-7.phoenixlidar.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs-7.phoenixlidar.com/lidarmill-desktop/workflow-kk/project-setup.md).

# Configuring Coordinate Reference System

## Summary 

Project Setup will step you through the process of opening SpatialExplorer for post processing, configuring a project datum, and loading files from a field acquisition.   

Begin by opening SpatialExplorer and selecting **Work Offline**. 

![](/files/-M_6oBIxrHiHB5tZQkjI)

Then use **File -> Open File**  and navigate to the PLP (Phoenix LiDAR Project) file located in the folder downloaded from your LiDAR system. If Imagery was collected during the mission, verify that it is within the camX folder located within the same folder as the PLP. Cameras with external storage will not automatically populate the camX directory, and these images must be moved into the directory from the camera storage manually. 

Next, configure the project Coordinate Reference System (CRS), located in the top right of the SpatialExplorer window:

![Project CRS prior to configuration](/files/AtghURcpDuFhtwc38fII)

Configure the horizontal and vertical CRS. Some users may find their CRS predefined under the **Well-known geographic-3D compound CRS**, however in most cases the user will need to select the horizontal and vertical CRS separately by selecting **User-defined compound CRS**. 

![Horizontal and vertical CRS selected, however no geoid grid has been selected yet. In this case, the vertical CRS (NAVD88) will require a geoid grid.](/files/S1LhPLpqEvgQWxwBLCjn)

{% hint style="info" %}
Some vertical coordinate reference systems will require a geoid grid. If a geoid grid is not required, such as when using ellipsoidal altitudes, SpatialExplorer will not allow you to select a grid.
{% endhint %}

To select a geoid, click **Select geoid** to access the Grids manager. Navigate to the geoid you require, or import a local file if necessary. If the geoid is already downloaded, you can select it and click **Use this grid**. If your geoid is not downloaded yet, you will need to first click the download icon to download the grid. 

![Geoid 2018 selected as the grid to use with NAVD88.](/files/9HPbVM6e104xTI1tVcic)

Once your geoid grid is selected, you should see it in the bottom window of the CRS menu:

![](/files/BX7IDHkJCWp5Y7JqVHsG)

Once your project CRS is configured, you should see the CRS listed in the top right of the SpatialExplorer window:

![CRS shown in the top right corner of SpatialExplorer](/files/d3ctNJN3l8NdPQYS9zFT)