# Field Data Check

1. Download data from the lidar system. Then, run SpatialExplorer and **File->Open** the PLP file.
2. Navigation system data check:
   1. Pay close attention to the [messages](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/windows/messages) window. Look for warnings in yellow regarding missing IMU samples and/or missing GNSS data. 
   2. If you have NavLab Embedded/InertialExplorer and a standalone reference station (as opposed to a public or virtual reference station), quickly process the trajectory via [NavLab Embedded](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/toolbars/workflow/navlab-embedded) to ensure the trajectory quality meets your expected standards. 
3. Lidar data check:
   1. [Build a pointcloud](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/toolbars/workflow/create-cloud) using the real-time trajectory.
      1. **For RIEGL users**: Fuse a [down-sampled pointcloud](https://docs.phoenixlidar.com/user-interface/windows/project/rover/lidars/lidar-processing-settings#downsampling-with-line-scanners). MTA ambiguities can create an excessive amount of noise. Depending on the number of MTA zones you encountered, it may be necessary to run [MTA disambiguation ](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/toolbars/workflow/lidar)prior to fusing a field check cloud.
      2. For RECON or Multi-laser users: Use the auto-downsampling slider, located in the[ lidar processing settings tab](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/windows/project/rover/lidars/lidar-processing-settings), to lower the density significantly (place the slider to fuse only 1/2 of the data). 
   2. Check that the cloud fully covers your AOI. You can import a KML geometry of your AOI using **File->Open**. 
   3. Visualize the cloud by [interval index ](https://docs.phoenixlidar.com/user-interface/windows/project/pointclouds#visualization)to ensure you achieved sufficient flightline overlap. Typically, all parts of the AOI should have at least two intervals present.  
4. Imagery QA/QC (if imagery was co-acquired). 
   1. For cameras with internal storage (A7R4, A7R4-lite, A7R2, IXM-50, IXM-100), check that the number of camera trigger events in the camera session(s), visible under [Camera->Acquisition](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/windows/project/rover/cameras/camera-acquisition-settings), matches the number of images recorded on the storage medium (SD or XQD memory card) .
   2. Check that the imagery is suitable for processing.
      1. Imagery generally matches the expected content.
      2. Imagery is not over-exposed, under-exposed, blurry, or particularly grainy. 

{% hint style="warning" %}
Some issues are not identifiable via a cursory field check. This workflow should be used just to identify the most common and obvious issues with acquired data. 
{% endhint %}