Estimate storage capacity with drone imagery

The Yucaipa Valley Water District (YVWD) needs to estimate the storage capacity of a storm water retention basin. On-site measurements cost time, money, and labor, so the district captured aerial imagery with a drone to help estimate the basin's volume.

In this tutorial, you'll convert drone imagery into elevation layers using ArcGIS Drone2Map. Then, in ArcGIS Pro, you'll use geoprocessing tools to estimate the basin's volume. Finally, you'll share the results with your YVWD colleagues in ArcGIS Online.

This tutorial was last tested on August 1, 2023, using ArcGIS Drone2Map 2023.1 and ArcGIS Pro 3.1. If you're using different versions of these applications, you may encounter different functionality and results.

Requirements

• ArcGIS organizational account with a Publisher, Facilitator, or Administrator role in an ArcGIS organization (see options for software access)
• ArcGIS Drone2Map Standard or Advanced.
• ArcGIS Pro
• ArcGIS Spatial Analyst extension

Generate the raster data

The Yucaipa Valley Water District (YVWD) took aerial imagery of its water recycling facility using a drone. The water recycling facility includes a storm water retention basin, which is the feature of interest in this tutorial. First, you'll use ArcGIS Drone2Map to convert the imagery into the following data products:

• True Ortho: An image composed of many smaller images aligned together
• Digital surface model (DSM): An image that shows the elevations of an area, including structures and vegetation
• Digital terrain model (DTM): An image that shows the ground elevation of an area, not including structures and vegetation

Note:

Because the drone images overlap partially, Drone2Map can do some computations on the back end to derive tridimensional elevation information. This process uses the structure from motion technique.

These datasets will provide you with imagery of the facility and the elevation data necessary for calculating the volume of the storm water retention basin.

Download the drone imagery

The images that the drone captured are stored online in a zipped file. You'll download the file, unzip its contents, and look at some of the images before you add them to a Drone2Map project.

1. Download the yvwd_images .zip file.

   The .zip file downloads to your computer.

2. Locate the downloaded file. Right-click the file and extract it to a location where you can easily find it, such as your Documents folder.
3. Open the yvwd-images folder.

   

   The folder contains 19 images.

4. Double-click the image named DJI_0984.

   A preview appears. The image shows a top-down view of the storm water retention basin that you'll measure later. The basin is empty, because each summer the YVWD cleans it out to get ready for the next rainy season. However, from this image, it's difficult to tell how deep the basin is.

   

5. Close the preview.

Create a Drone2Map project

Next, you'll create a project in Drone2Map and add the drone images.

1. Open ArcGIS Drone2Map.
2. If prompted, sign in using your licensed ArcGIS account.

   Note:

   If you don't have an organizational account, see options for software access.

   The application opens. First, you'll give your project a name.

3. Under Give Your Project a Name, type YVWD Basin.

   

   Next, you'll specify where your project data will be stored.

4. Click Browse to choose the location on your computer to store your project's data.

   Now, you'll add the 19 images you downloaded into the project

5. Click Add Folder.

   

   The Browse for Image Folder window appears.

6. Browse to and select the yvwd-images folder. Click OK.

   The images are loaded into the project and their information is visible in the table.

   

   Each image has a Lat [Y] (degrees latitude), Long [X] (degrees longitude), and Alt [Z] (height) attribute. These geographic attributes were stored by the drone when it captured each image, allowing the images to be located on a map. For these images, the default coordinate system is acceptable.

   As a final step in creating your project, you'll choose a template. You can choose from several project templates based on the type of data you'll create. The data types that you are interested in, which are True Ortho, DTM, and DSM, belong to the 2D category, because they are made of 2D rasters. A raster is a grid in which each cell (or pixel) contains one value. For instance, in the case of the DTM or the DSM, each cell contains a terrain elevation value.

7. On the template drop-down menu, click 2D Products Template.

   

8. Click the Create button.

   A map is created with 19 points, where each point represents an image captured by the drone. The points are connected by orange lines; these lines represent an estimation of the flight path that the drone took to capture the images. The drone images themselves do not display on the map.

   

Process the data

To convert the images into data products that you can use in analyses, you need to process them. Because you chose 2D Products Template. The project is automatically set to generate a True Ortho and a DSM. Since you'd also like a DTM, you'll have Drone2Map generate this product as well.

Note:

It is possible to choose custom settings by clicking Options on the ribbon's Home tab in the Processing group.

1. In the Manage pane, under 2D Products, ensure that Image Collection, True Ortho, and Digital Surface Model are checked.

   

2. Under 2D Products, check the box next to Digital Terrain Model.

   

   A DTM will be created when you process the drone imagery.

3. On the ribbon, ensure that the Home tab is selected. In the Processing group, click Start.

   

   The processing begins.

   Note:

   The process may take 15 minutes or more to complete. This time may vary depending on your computer's hardware.

   Three new datasets are added to the Contents pane: True Ortho, Digital Surface Model, and Digital Terrain Model.

   Currently, you can only see the True Ortho. You'll explore the DSM and DTM next.

   

4. In the Contents pane, turn off the True Ortho layer.

   

   The DSM is visible. The DSM is a raster representing the elevation of the area, including structures and vegetation.

   

5. In the Contents pane, turn off the Digital Surface Model layer.

   The DTM is visible.

   

   The DSM and DTM look relatively similar in this case, but the DTM is smoother and most buildings and vegetation have been removed.

   Next, you'll look at these three layers in 3D.

6. In the Contents pane, turn on the Digital Surface Model and True Ortho layers.
7. Drag the True Ortho layer to the 3D Map view. When the 3D scene appears, place the imagery anywhere in the scene.
8. If necessary, in the Contents pane, right click True Ortho and choose Zoom to Layer. Explore the 3D scene.

   Note:

   For help with exploring 3D scenes, refer to the Navigation or the on-screen navigator help topics.

   You can see the relative size of the basin.

   

9. Add the Digital Surface Model and Digital Terrain Model layers from the 2D Map view to the 3D Map view.
10. Turn the True Ortho, DTM, and DSM layers on or off to visualize each of them, paying special attention to the retention basin.
11. On the toolbar, press Save.

    

In this module, you converted drone imagery into three data products: a True Ortho, a DSM, and a DTM. Next, you'll compute the volume of the basin using ArcGIS Pro.

Estimate volume

You'll now calculate the basin's total capacity. To do so, you'll use geoprocessing tools in ArcGIS Pro.

Open the project in ArcGIS Pro

First, you'll convert your Drone2Map project to an ArcGIS Pro project.

1. In Drone2Map, click the 2D Map view.
2. In the Contents pane, turn off and collapse the Project Data group.

   

3. Save your project.
4. On the ribbon, on the Home tab, in the Post-Processing group, click Open in ArcGIS Pro.

   

5. In the Open in ArcGIS Pro window, click Yes.

   ArcGIS Pro opens.

6. If prompted, sign in using your licensed ArcGIS account.

   Note:

   If you don't have access to ArcGIS Pro or an ArcGIS organizational account, see options for software access.

   All of the elements that were present in your Drone2Map project are now present in your ArcGIS Pro project.

   

7. Close Drone2Map.

   Note:

   If you need to reopen the Drone2Map project, go to the YVWD Basin project folder on your computer and double-click the YVWD Basin.d2mx file.

Fill sinks with a geoprocessing model

To compute the basin's volume, you'll use the DTM as your primary dataset, since it provides elevation data for the entire basin surface.

The first geoprocessing tool you'll use is the Fill tool. This tool fills any sinks it finds in elevation data and produces a new raster with the updated elevation values. Sinks are areas where the elevation is lower than all areas around it: water that flows into a sink won't be able to flow out of it. The storm water retention basin is a sink. By filling it, and then comparing the filled elevation to the basin's original elevation, you can determine the volume capacity.

How Fill works: the original DTM (in green) and the filled sink (in red) are shown.

1. On the ribbon, click the Analysis tab. In the Geoprocessing group, click Tools.

   

   The Geoprocessing pane appears. You can use this pane to search for tools.

2. In the search, type Fill. In the list of results, click the Fill tool.

   

3. In the Fill tool pane, set the following parameters:
   • For Input surface raster, choose DEM Products\Digital Terrain Model.
   • For Output surface raster, clear any text and type Fill_Result.

   

   Before running this tool, you'll set it to only process the basin by updating the tool's environments. In particular, you'll set the Processing Extent to use the map's visible extent when the Fill tool is run.

4. Click the Environments tab.
5. In the 2D Map view, zoom in and adjust the map's extent until only the basin is visible.

   

   Tip:

   For more precise map navigation, go to the Map tab. In the Navigation group, use the Fixed Zoom In and Fixed Zoom Out tools.

6. In the Geoprocessing pane, under Processing Extent, set Extent to Current Display Extent.

   

7. Click Run.

   When the processing is complete, the new layer, Fill_Result, appears in the Contents pane and on the map. The Fill tool filled all the depressions in the DTM elevation surface for the area visible on the map. Next, you'll use the Cut Fill tool, which calculates the volume change between two surfaces: in this case, the original Digital Terrain Model and Fill_Result layers.

8. In the Geoprocessing pane, click the Back button twice.

   

9. Search for and open the Cut Fill tool.

   Note:

   You can use the Cut Fill tool from either the 3D Analyst or Spatial Analyst Tools.

10. Set the following Cut Fill tool parameters:
    • For Input before raster surface, choose DEM Products\Digital Terrain Model.
    • For Input after raster surface, choose Fill_Result.
    • For Output raster, clear any text and type Volume_Raster.

    

11. Click Run.
12. Zoom out to see the results.

    When the process is complete, the new Volume_Raster layer appears.

    

    Each red shape that you see is considered a separate feature. You'll now open the Volume_Raster attribute table to identify the largest shape which represents the retention basin. This will provide you with the basin's volume.

13. In the Contents pane, right-click Volume_Raster and choose Attribute Table.

    

    The attribute table contains a field, Volume, with volume measurements for each sink. You'll sort the sinks from largest to smallest volume.

    Note:

    The volume values are all expressed as negative numbers because when you used the Cut Fill tool, you subtracted the higher elevation from the lower.

14. Right-click the column header for Volume and choose Sort Ascending.

    

15. Click the cell next to the top row to select it.

    

    This largest sink represents the storm water retention basin. You can see that it is by far the largest volume, about 3,159.8 versus 12.9 for the second-ranked sink. The other filled areas correspond only to tiny sinks caused by minor terrain variations.

    Note:

    Your values may vary slightly.

    The volume for the basin is 3,159.8, but the unit is not stated. You'll now identify the units used.

16. In the Contents pane, right-click the Volume_Raster layer and choose Properties.
17. In the Layer Properties window, click the Source tab.

    Under Data Source, the Vertical Units are set to Meter.

    

    This unit type indicates that the Volume field was calculated in cubic meters. Hence, the volume of the retention basin is approximately 3,159.8 cubic meters.

18. Close the Layer Properties window and the Volume_Raster attribute table.

Create a polygon feature class

For now, the basin has been only identified as a raster, Volume_Raster. To add to a map, it will be more convenient to have the basin represented as a polygon that shows the boundaries of the basin. You'll use the Raster to Polygon tool, which converts a raster dataset to polygon features.

1. In the Geoprocessing pane, click the Back button. Search for and open the Raster to Polygon tool.
2. Set the following Raster to Polygon tool parameters:
   • For Input raster, choose Volume_Raster.
   • For Field, keep Value.
   • For Output polygon features, clear any text and type Retention_Basin.
   • Uncheck the Simplify polygons box.

   

3. Click Run.

   A polygon layer is added to the map. Since you had the basin polygon selected from the Volume_Raster layer, only that feature is converted to a polygon when the tool is run.

4. In the Contents pane, turn off the Volume_Raster and Fill_Result layers.

   The Retention_Basin layer contains a single polygon that represents the basin. It displays on top of the imagery.

   

   Although you have the polygon representing the basin, the attribute for its volume was not preserved when you ran the Raster to Polygon tool. You'll resolve this next.

5. In the Contents pane, right-click Retention_Basin, and choose Attribute Table.

   As mentioned, the Volume field was not passed from the original raster dataset. You'll add it back with the Join Field tool, using the gridcode attribute.

6. In the Geoprocessing pane, click the Back button. Search for and open the Join Field tool.
7. Set the following Join Field tool parameters:
   • For Input Table, choose Retention_Basin.
   • For Input Join Field, choose gridcode.
   • For Join Table, choose Volume_Raster.
   • For Join Table Field, choose Value.
   • For Transfer Fields, choose Volume.

   

8. Click Run.

   The Volume field is now added to the Retention_Basin attributes.

   

9. Close the attribute table.
10. Save the project.

In this module, you opened several data products representing the retention basin in ArcGIS Pro. Then, you used geoprocessing tools, such as Fill and Cut Fill, to estimate the basin's volume.

Share the results

Previously, you estimated the volume of the retention basin. Next, you'll symbolize the basin and configure pop-ups to convey the most relevant information. Then, you'll share the results as a map package.

Style the layer

You intend to share the map as a package, so you'll remove any unnecessary layers. You'll also change the Retention_Basin layer's style to an outline with no fill. That way, users can see the imagery of the basin under the layer.

1. In the Contents pane, right-click the Volume_Raster layer, and choose Remove.

   

2. Similarly, remove all layers except Retention_Basin, True Ortho, and the basemap layers.

   

   Next, you'll change the Retention_Basin layer's symbology.

3. Click the symbol under Retention_Basin.

   

   The Symbology pane appears.

4. If necessary, at the top of the Symbology pane, click Gallery.
5. In the list of symbols, click the Black Outline (2 pts) symbol.

   Tip:

   To see a symbol's full name, point to it.

   

   The map updates. The basin is now symbolized with an outline, and users can see the imagery.

   

6. Close the Symbology pane.

Configure pop-ups

The Retention_Basin layer is now displaying as desired. To ensure that users see meaningful information, you'll configure the pop-up to display only the basin's area and volume.

1. On the map, click anywhere on the retention basin area to display the pop-up.

   

   The pop-up contains a lot of information that isn't necessary for the YVWD staff to see, such as the feature's Id and gridcode attributes. Also, the volume value is negative and its unit of measurement isn't clear.

2. In the Contents pane, right-click Retention_Basin and choose Configure Pop-ups.

   .

   The Configure Pop-ups pane appears. Pop-ups can be configured using ArcGIS Arcade expressions. You'll use an expression to convert the area and volume values into the units requested by YVWD.

3. At the bottom of the Configure Pop-ups pane, click Expressions.

   .

4. Click New.

   .

   The Expression Builder window appears. First, you'll add an expression to display the area of the basin in thousands of square feet. This expression will do two things:

   • Multiply by 10.7639 to convert from square meters to square feet.
   • Divide by 1,000 to get the area in thousands of square feet.
5. In the Expression Builder, enter the following values:
   • For Name, type Area.
   • For Title, type Area.
   • For Expression, type (or copy and paste) ($feature.Shape_Area*10.7639)/1000.

   

6. Click OK.

   Next, you'll add an expression to show the volume in millions of gallons. This expression will do three things:

   • Multiply by 264.172 to convert from cubic meters to gallons.
   • Divide by 1,000,000 to get the volume in millions of gallons.
   • Multiply by -1 to make the number positive.

   You'll use text later to explain the units.

7. In the Configure Pop-ups pane, click New.
8. In the Expression Builder, enter the following values:
   • For Name, type Volume.
   • For Title, type Volume.
   • For Expression, type ($feature.VOLUME*-264.172)/1000000.

   

9. Click OK.

   Both expressions are configured. Next, you'll add the expressions and relevant text to the pop-up.

10. In the Configure Pop-ups pane, click the Back button.

    

    First, you'll change the pop-up title.

11. Click {Id} to edit the title of the pop-up.

    

12. Under Title Options, replace the existing text with Retention Basin Capacity. Click the Back button.

    

    Currently, the pop-up content is a list of attribute fields. You'll change it to text that you can customize.

13. Click the Text button.

    

    A Text object is added to the list of pop-up elements.

14. Next to the Text object, click the Edit pop-up element button.

    

15. Delete any existing text, and type Area = followed by a space.
16. Click Field and choose Area {expression/Area}.

    

17. Add another space and type thousand square feet.

    Together, it reads Area = {expression/Area} thousand square feet.

18. Press Enter. On the next line, similarly, create the string Volume = {expression/Volume} million gallons.

    

19. Click the Back button.

    Now that you have formatted the pop-up to include the most relevant information, you no longer need to show all of the fields.

20. Next to Fields(8), click the Remove pop-up element button.

    

21. On the map, click the Retention_Basin feature to view the updated pop-up.

    

    The retention basin has an area of over 35,000 square feet and a capacity to hold almost 1 million gallons of water.

22. Close the pop-up and the Configure Pop-ups pane. Save the project.

Publish the map

Your map has been symbolized and its pop-ups are configured. Next, you'll publish your results as a map package to ArcGIS Online, where you can share it with the YVWD staff.

1. On the ribbon, click the Share tab. In the Package group, click Map.

   

   The Package Map pane appears.

2. In the Package Map pane, enter the following values:
   • For Name, type YVWD_Retention_Basin.
   • For Summary, type This map shows the Yucaipa Valley Water District's recycled water facility and stormwater retention basin capacity.
   • For Tags, type Yucaipa, stormwater, and basin.

   

3. If necessary, for Share with, check the box next to your organization.

   You'll analyze the data before sharing it to make sure there are no major errors.

4. At the bottom of the Package Map pane, click Analyze.

   

   No errors or warnings are found.

5. Click Package.

   After a few minutes, the map is successfully packaged and stored on ArcGIS Online.

6. In the Package Map pane, click the Manage the package link to find the package in your ArcGIS Online account.

   

   The YVWD staff will be able to easily access that packaged map and open it in ArcGIS Pro.

7. In ArcGIS Pro, close the Package Map pane.
8. Save the project.

In this tutorial, you created several data products from drone imagery of a retention basin with Drone2Map and added them to an ArcGIS Pro project. Then, you used geoprocessing tools to estimate the basin's volume. Finally, you configured the map and published it as a packaged map to ArcGIS Online.

You can find more tutorials such as this on the Introduction to Imagery & Remote Sensing page.