Pix4Dmapper calculates the volume following:

1. The user draws a volume in the Volumes view. For more information about how to draw a Volume: 202560319

Figure 1. Volume drawn in the Volumes view. |

Figure 2. The Base of the volume. |

2. Pix4Dmapper projects a grid with GSD spacing on the base.

Figure 3. Projected grid on the base of the volume: This drawing is a sketch and does not depict the real dimensions of the grid. The grid has very small interval (the GSD). |

3. For each cell i of the grid, its volume (V_{i}) is given by:

*V _{i }= L_{i }* W_{i} * H_{i}*

Where:

*L _{i }*= the length of the cell.

W

*the width of the cell.*

_{i}=*H*the height of the cell.

_{i}=The Lenght (Li) and Width (Wi) are equal to the project's GSD.

*L _{i }=W_{i }= GSD_{}*

The Height (H* _{i}*) is given by:

*H _{i} = *

*Z*

_{Ti }- Z_{Bi}*Where: *

*Z _{Ti}* = the terrain altitude of each cell at the center of the cell.

*Z*= the base altitude of each cell at the center of the cell.

_{Bi}Therefore, the volume *V _{i }*of cell i is given by:

*V _{i }= GSD*GSD* (Z_{Ti }- Z_{Bi})*

Figure 4: Volume of one cell of the base |

4. Pix4Dmapper calculates 2 volumes:

- The Cut volume
*V*is the volume between the base and the 3D terrain, when the terrain is higher than the base._{c }

*Cut volume = V _{C }*

*=*V

_{C}

_{1 }+ V

_{C}

_{2}+...V

_{C}

_{N}

Where:

*V _{C}*

_{1...N}= Cut volume for cell i..N

*The Fill volume**V*is the volume between the base and the terrain when the terrain is lower than the base._{F }

*Fill volume = V _{F }*

*=*V

_{F}

_{1 }+ V

_{F2}+...V

_{F}

_{N}

Where:

*V _{F}*

_{1...N}= Fill volume for cell i...N.

5. The Total volume is given by:

*Total Volume = V _{T }= *

*V*

_{C }+*V*

_{F}

For more information about the error in Volume calculation: 202559219.