Exporting a vegetation analysis
Vegetation analysis export is available to an acoustic variable with an associated line that represents a vegetation boundary. A vegetation line may be detected by the Threshold offset operator. In Echoview, there are also other ways to create a line that represents a vegetation boundary.
Prior to exporting a Vegetation analysis:
- Detect a line that represents a vegetation boundary.
- Create or choose a line to represent the acoustic bottom or bottom of the vegetation. This line will be used as a Bottom line setting.
- Select a suitable acoustic variable and specify that variable's Vegetation settings on the Analysis page of the Variable Properties dialog box.
You must specify:
- A Vegetation line that represents a vegetation boundary.
- A Bottom line that represents the bottom of the vegetation or acoustic bottom.
- An interval size and interval unit that together with the Vegetation and Bottom lines represents a vegetation analysis calculation interval.
- Consider using a Minimum threshold on the Data page of the Variable Properties. Such a threshold can apply a useful constraint to a vegetation analysis.
To export a Vegetation Analysis:
- Display a prepared acoustic variable as discussed above.
- Click the Echogram menu and select Export, Vegetation Analysis.
- Enter a name under File name.
- Click OK.
Vegetation analysis file format (*.csv)
The first row of the file records the (comma separated) names of the export data. Subsequent rows record the (comma separated) values of the export data of each vegetation analysis interval.
| Variable name | Description | |
| Process_ID | Refer to Process_ID. | |
| Interval | Vegetation analysis interval number. The size and type of interval are specified by Time/Ping and Time between intervals (minutes). Intervals are numbered with an integer, beginning from 1 and the left side of the echogram. When working with transects, analysis interval numbers match the grid interval numbers. | |
| Ping_S | Start ping for the vegetation analysis interval. | |
| Ping_E | End ping for the vegetation analysis interval. | |
| Date_M | Date (yyyyMMdd) of the middle ping for the vegetation analysis interval. | |
| Time _M | Time (HH:mm:ss.ssss) of the middle ping for the vegetation analysis interval. | |
| Lat_M | Latitude (decimal degrees) of the middle ping for the vegetation analysis interval. | |
| Lon_M | Longitude (decimal degrees) of the middle ping for the vegetation analysis interval. | |
| Bottom_line_depth_mean | Mean depth (m) of the Bottom line for the vegetation analysis interval. | |
| Bottom_line_depth_min | Minimum depth (m) of the Bottom line for the vegetation analysis interval. | |
| Bottom_line_depth_max | Maximum depth (m) of the Bottom line for the vegetation analysis interval. | |
| Vegetation_line_depth_mean | Mean depth (m) of Vegetation line for the vegetation analysis interval. | |
| Vegetation_line_depth_min | Minimum depth (m) of the Vegetation line for the vegetation analysis interval. | |
| Vegetation_line_depth_max | Maximum depth (m) of the Vegetation line for the vegetation analysis interval. | |
| Vegetation_line_height_mean | Mean height (m) of vegetation between the Bottom and Vegetation lines of the vegetation analysis interval. -9.9e+37 is exported when the Bottom line is above the Vegetation line. |
|
| Vegetation_line_height_min | Minimum height (m) of vegetation between the Bottom and Vegetation lines of the vegetation analysis interval. -9.9e+37 is exported when the Bottom line is above the Vegetation line. |
|
| Vegetation_line_height_max | Maximum height (m) of vegetation between the Bottom and Vegetation lines of the vegetation analysis interval. -9.9e+37 is exported when the Bottom line is above the Vegetation line. |
|
| Vegetation_line_height_standDev | Standard deviation of the vegetation height (m) between the Bottom and Vegetation lines of the vegetation analysis interval. -9.9e+37 may be exported when:
|
|
| Pings_With_Vegetation | Number of pings with vegetation for the vegetation analysis interval. -9.9e+37 is exported when the Bottom line is above the Vegetation line. |
|
| Samples_in_Domain | Number of samples with midpoints included within the vegetation analysis interval. This can be affected by Exclusion lines and specified Data page thresholds. -9.9e+37 is exported when the Bottom line is above the Vegetation line. |
|
| Samples_above_min_threshold | Number of samples with midpoints above the Minimum threshold for the vegetation analysis interval. -9.9e+37 is exported when the Bottom line is above the Vegetation line. |
|
| Transect_ID | It is the integer representing the index or transect number. This variable is automatically exported if there is an assigned transect group. If no transect group is present, this column will not be present. |
|
| Transect_name | It is the unique string identifier for the transect in the transect group. This variable is automatically exported if there is an assigned transect group. If no transect group is present, this column will not be present. | |
Notes:
- -9.9e+37 is exported for variables and 999 is exported for Lat_M and Lon_M and when there is no vegetation line.
- Missing line segments in the Threshold offset line or Operand 2 line or crossed Threshold offset and Operand 2 lines are counted as no data and will not contribute to statistical vegetation analysis calculations.
- Bad data (no data) and Bad data (empty water) samples are handled as for integration analysis export. For more information refer to About analysis domains: Analysis_regions_and_samples.
- Samples with midpoints outside the region enclosed by the vegetation line and bottom line are no longer being included in the counts for Samples_in_domain and Samples_above_min_threshold. Note that this may cause a difference in vegetation analysis results between Echoview 14 and Echoview 15.