The Mensuration Options pane is where you set the parameters for defining your measurements of features and objects visible in your imagery and raster datasets. The types of parameters you can define include measurement units, symbols and colors representing Measurement Types, and the Level of Precision for your measurements. You can specify an Elevation file to increase measurement accuracy, or to compute Volume measurements.
The Level of Precision value determines the number of decimal places for the specified units; the default value is four decimal places.
Different Symbol types can be selected by clicking on the default symbol for each Measurement Type. The Color can be assigned to the different symbol and measurement types by clicking on the color drop-down arrow and choosing a color from the color pallette or assigning a unique color using the Color Editor.
Measurement accuracy can be increased by assigning an elevation dataset from the file navigation icon. An elevation can be specified as an elevation file or the URL address of an elevation service.
Mensuration Options pane
On the Imagery tab, in the Mensuration group, click Mensuration Options to open the Mensuration Options pane.
Specify the units for each of the measurement tools.
Each of the measurement types can be represented with a unique symbol and color. Click the symbol to open the Symbols pane, which displays the gallery of symbols for each data type, such as point, line, polygon, and text. Click the drop-down arrow next to the color chip to display the color palette and properties dialog box.
You can increase the accuracy of the measurement calculations by incorporating an elevation dataset.
The Volume measurement tool will only be enabled after you specify an elevation dataset.
If you are working in an Ortho Mapping workspace where digital surface model (DSM) and digital terrain model (DTM) products have been generated and are available as layers in the Contents pane, they can be selected as Elevation input layers using the drop-down list.
When you're working in an Ortho Mapping workspace and a DSM or DTM are specified as the Elevation input, the error of the volume measurement is also calculated.
The volume measurement is calculated from a reference surface determined by the polygon delineating the object you want to measure. The reference surface—called the Base Surface—is created using different methods as options:
- Constant—A user defined value that defines a flat base surface
- Interpolate—Uses the z-value at each vertex in your sketch to interpolate a base surface for the volume calculation.
- Minimum—Uses the minimum z-value found in the sketch vertices to define a flat base surface at the minimum elevation.
- Maximum—Uses the maximum z-value found in the sketch vertices to define a flat base surface at the maximum elevation
- Mean—Uses the mean z-value from the sketch vertices to define a flat base surface at the mean elevation.