Prepare survey data

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Before you can generate depth areas, you must do the following:

• Prepare raster data or point data—Data must be converted to a triangulated irregular network (TIN) to be used to generate depth areas. The process for generating the TIN varies depending on whether the input is point data or raster data. Raster data can be converted using the Raster To TIN tool. Point data requires additional processing before it can be used to create a TIN.
• Generate depth contours.

Both the TIN and the depth contours are necessary to run the Generate Depth Areas tool.

Prepare raster data for generating depth areas

You can use the Raster to TIN tool to convert raster data to TIN data. The TIN you create will be used to generate contours.

Примечание:

A 3D Analyst extension license is required to use the Raster to TIN tool.

Complete the following steps to create a TIN layer for generating depth areas:

1. Start ArcGIS Pro.
2. Open a new or existing project.
3. On the Analysis tab, in the Geoprocessing group, click Tools .

   The Geoprocessing pane appears.

4. In the Geoprocessing pane, click the Toolboxes tab, and expand 3D Analyst Tools.
5. Click Raster > Conversion > Raster To TIN.

   The Raster to TIN tool opens.

6. Configure the Raster To TIN tool parameters:
   1. For the Input Raster parameter, use the raster that contains bathymetric data.
   2. For the Output TIN parameter, provide the location where you want to save the TIN.
   3. Ensure that the Maximum Number of Points parameter value matches the number of individual pixel values of the raster.
   4. Set the Z Tolerance parameter to 0.

      Setting the Z Tolerance parameter to 0 ensures that the depth value is not altered during conversion.

   5. Leave the default values for all other parameters.
7. Click Run to generate the TIN dataset.

   A TIN dataset is generated from the input data.

8. Optionally, use the Smooth Bathymetric TIN tool to perform a shallow-biased smoothing of the generated TIN to cartographically improve the appearance of the contours and depth areas.

   It is recommended that you smooth the TIN to reduce vertex density and the potential for topological issues in the generated depth contours. The Smoothing Iterations value should increase for smaller scale charts to apply generalization more appropriate for the scale.

   Примечание:

   If you smooth the TIN, you must use the smoothed TIN and contours created from the smoothed TIN as the inputs to the Generate Depth Areas tool.

You now have a TIN that can be used to create depth contours.

Prepare point data for generating depth areas

To properly create a TIN from point data, you need to know several things about the data, including the minimum and maximum depths, whether the data is positive up or positive down, and the average point spacing. You can use the Point File Information tool to get this information.

Примечание:

A 3D Analyst extension license is required to use the Point File Information tool.

Point data can come in a variety of formats. Since x,y,z data is one of the most common formats used in navigational charting, this workflow focuses on starting with x,y,z data. If you have point data in a geodatabase, you can proceed to creating a TIN.

Generate an information-attributed polygon

Complete the following steps to generate an information-attributed polygon:

1. Start ArcGIS Pro.
2. Open a new or existing project.
3. On the Analysis tab, in the Geoprocessing group, click Tools .

   The Geoprocessing pane appears.

4. In the Geoprocessing pane, click the Toolboxes tab, and expand 3D Analyst Tools.
5. Click the Statistics toolset, and click Point File Information.

   The Point File Information tool opens. The output of this tool is a polygon attributed with information that is used later in the survey data preparation process.

   Примечание:

   A 3D Analyst extension license is required to use the Point File Information tool.

6. Configure the Point File Information tool parameters:
   1. For the Point Data parameter, use the file containing the x,y,z data.
   2. For the Output Feature Class parameter, provide the location where you want to save the feature class.
   3. For the File Format parameter, choose ASCII file with XYZ.
   4. For the Coordinate System parameter, provide the coordinate system of the x,y,z data.
   5. For the Decimal Separator parameter, specify the value based on the x,y,z data format.
7. Click Run.

   A polygon attributed with the point data information is generated.

8. In the Contents pane, right-click the output layer from the Point File Information tool and click Attribute Table.

   The attribute table contains statistical information about the point data:

   Attribute value	Description
   Pt_Spacing	The average space between points in the dataset
   Z_Min	The minimum z-value (if the data is positive up)
   Z_Max	The maximum z-value (if the data is positive up)

   The range of Z_Min and Z_Max values allows you to determine whether the data is positive up or positive down. In positive down data, maximum depth and minimum depth values are positive with drying heights as negative. In positive up data, the maximum depth and minimum depth values are negative with drying heights as positive. The Pt_Spacing value is used in the ASCII 3D To Feature Class tool.

Generate a multipoint feature class

Complete the following steps to generate a multipoint feature class using the information-attributed polygon created with the Point File Information tool:

1. In the Geoprocessing pane, click the Back button to return to the Toolboxes list.
2. In the Geoprocessing pane, click 3D Features > Conversion.
3. Click ASCII 3D To Feature Class to convert the x,y,z file to a multipoint feature class.
4. Configure the ASCII 3D To Feature Class tool parameters:
   1. For the ASCII 3D Data parameter, use the file that contains the x,y,z data.
   2. For the File Format parameter, choose XYZ.
   3. For the Output Feature Class parameter, provide the location where you want the feature class to be stored.
   4. For the Output Feature Class Type parameter, keep the default Multipoint features value.
   5. For the Coordinate System parameter, provide the coordinate system of the x,y,z data.
   6. For the Average Point Spacing parameter, provide the value from the Pt_Spacing attribute from the polygon output of the Point File Information tool.
   7. For the Decimal Separator parameter, specify the value based on the x,y,z data format.
   8. Leave the default values for all other parameters.
5. Click Run.

   A multipoint feature class is generated.

Create a TIN

Complete the following steps to create a Triangulated Irregular Network (TIN) using the multipoint feature class created with the ASCII 3D To Feature Class tool:

1. In the Geoprocessing pane, click the Back button to return to the Toolboxes list.
2. Click TIN Dataset and click Create TIN.
3. Configure the Create TIN tool parameters:
   1. For the Output TIN parameter, provide the location where you want to save the TIN.
   2. For the Coordinate System parameter, provide a suitable projected coordinate system.
   3. For the Input Feature Class parameter, provide the multipoint feature class that was generated from the ASCII 3D To Feature Class tool.
   4. Leave the default values for all other parameters.
4. Click Run to generate the TIN dataset.

   A TIN dataset is generated from the input data.

The resulting TIN has connections between points that are not valid, since there is no limit on the length of the edges used to connect points during the triangulation. The Delineate TIN Data Area tool can be used to eliminate the long connections.

Delineate the TIN

To use the TIN created with the Create TIN tool to generate depth areas, you must first process it with the Delineate TIN Data Area tool to eliminate long connections. Complete the following steps to delineate the TIN:

1. In the Geoprocessing pane, click the Back button to return to the Toolboxes list.
2. Click TIN Dataset > Delineate TIN Data Area.
3. Configure the Delineate TIN Data Area tool parameters:
   1. For the Input TIN parameter, provide the TIN dataset generated from the Create TIN tool.
   2. Provide a value for the Maximum Edge Length parameter.

      Примечание:

      Connections between points are removed based on the maximum edge length. When working with irregularly spaced points, the recommended value for the maximum edge length is two times the square root of the average point spacing.

   3. Leave the default values for all other parameters.
4. Click Run.
5. Optionally, use the Smooth Bathymetric TIN tool to perform a shallow-biased smoothing of the generated TIN to cartographically improve the appearance of the contours and depth areas.

   It is recommended that you smooth the TIN to reduce vertex density and the potential for topological issues in the generated depth contours. The Smoothing Iterations value should increase for smaller scale charts to apply generalization more appropriate for the scale.

   Примечание:

   If you smooth the TIN, you must use the smoothed TIN and contours created from the smoothed TIN as the inputs to the Generate Depth Areas tool.

You now have a TIN that can be used to create depth contours.