Use tile-based processing

In ArcGIS Drone2Map, True Orthos, Digital Surface Models and point clouds can be generated as tiles and merged together. The existence of these tiles allows you to reprocess portions of the imagery rather than the whole product. This saves time and allows you to iterate corrections on the outputs to achieve your ideal product. When you uncheck the delete tiles processing option and draw a correction feature or waterbody mask over an existing product, Drone2Map automatically submits only the tiles that contain those features for reprocessing. This drastically reduces the time it takes to generate a new image and refine features within the project area.

There are two methods of applying the tile-based processing workflow: merged and unmerged. Using merged tiles will reprocess tiles and overwrite the product leaving a single output file while also saving storage space. Using unmerged tiles will output the individual tiles into the project folder and allows you to see which specific tiles were updated. In both cases, backups of the original products are stored within the project folder.

Process merged tiles

By default, True Ortho and DSM products have the processing options of merging and deleting tiles enabled. Tiles are generated as intermediate data and deleted once they are merged into a single raster with the original product being overwritten and the preprocessing features applied. However, if the area of interest is difficult to reconstruct or storage space is not an issue, then you can uncheck delete tiles and still use the merge tiles option.

DSM and 3D point clouds can be processed as merged tiles by selecting the LAS format and enabling the Merge LAS Tiles processing option.

Draw features and iteratively process to make tile-based corrections.

1. From the Home tab, use the Options button in the Processing group to open the Options window.
2. Browse to the 2D Products or 3D Products tab, depending on the product.
3. Check the box next to the product to enable it for processing.

   If processing a point cloud also enable the LAS and Merge LAS Tiles options.

4. Click Apply and click OK.
5. Use the Start button on the Home tab to begin processing.
6. Once processing completes, click either the Waterbody Mask or Correction Feature drop-down menu on the Home tab.

   Note:

   If you are using a correction feature, define the correct geometry type first. See: correction feature

7. Choose the Create Waterbody or Create Correction Feature option.

   The Create Features pane appears and automatically starts an edit session with the polygon template enabled for drawing.

8. Draw a new feature over any areas needing modification.
9. Click the Finish button on the editing toolbar in the map window.
10. Close the Create Features pane.
11. Click Start to reprocess the tiles with your drawn features.

    Once processing completes, review the result. You may need to uncheck the preprocessing layers to see the changes. Subsequent runs of the workflow will created a backup of the previously processed product.

Process unmerged tiles

You can configure True Orthos, DSM products to be created without the Merge Tiles option. This generates all imagery separated into individual tiles, which are stored as .tiff files and use a virtual raster file (.vrt) to reference and mosaic them. A .vrt file uses XML to contain all the parameters of the raster dataset. It allows you to mosaic multiple rasters together that are referenced by single file. This reduces intermediate data size and cuts down on processing complexity. These tiles can have correction or waterbody features drawn over them and can be reprocessed.

Point cloud products can be generated as individual LAS tiles by checking the LAS format option.

Choose which tiles are used with unmerged tile-based processing.

1. From the Home tab, use the Options button in the Processing group to open the Options window.
2. Browse to the 2D products or 3D products tab.
3. Check the box next to the product to enable it for processing.
4. If you are processing a True Ortho or Digital Surface Model, uncheck the Merge Tiles and Delete Tiles check boxes under the product. Alternatively, if you are processing a point cloud, enable the LAS format option under the product.
5. Click Apply and click OK.
6. Use the Start button on the Home tab to begin processing.

   Ensure that the product is checked in the Manage pane before processing.

   2D products will be added to the Imagery Products group in the Contents pane. This is a .vrt file that is referencing the tiles in the product folder. 3D products will be added to 3D Products group in the Contents pane and will appear as a set of LAS tile footprints on the map.

7. Once processing completes, click either the Waterbody Mask or Correction Feature drop-down menu on the Home tab.

   Note:

   If you are using a correction feature, define the correct geometry type first. See: correction feature

8. Choose the Create Waterbody or Create Correction Feature option.

   The Create Features pane appears and automatically starts an edit session with the polygon template enabled for drawing.

9. Draw a new feature over any areas needing modification.
10. Click the Finish button on the editing toolbar in the map window.
11. Close the Create Features pane.
12. Check on the product in the Manage pane.
13. Click Start to reprocess the tiles with your drawn features.

    Once processing completes, review the result. You may need to uncheck the preprocessing layers or refresh the map to see the changes.

14. Verify the new tile has been created.

    The tiles can be viewed from the Catalog pane by navigating to the products folder (For example: Project Folder > Results > True_Ortho). The .tiff or .las files are the individual tiles. When you hover over them, a pop-up appears with details. The tiles that were most recently modified were the ones that were reprocessed. You can also view their details in Microsoft File Explorer.