The **Map Coordinates** tool specifies the relationship between
volume data grid indices and Cartesian
coordinates. This information is included in the header when a map is
saved.
See also:
**Volume Viewer**,
**volume** operations,
**getcrd**,
measurements

**Map Coordinates** can be started
from the **Volume Data** section of the **Tools** menu
(more...).

The **Map** of interest should be chosen from the pulldown menu of open
volume data models.

**Origin index** – space-separated grid indices of the XYZ origin
(Cartesian 0,0,0).
Fractional and negative values are allowed, as the origin is not required
to coincide with a grid point or even to fall within the grid.
Clicking **center** moves the XYZ origin to the center of the grid,
whereas clicking **reset** restores the original values.

**Voxel size** – grid spacing (resolution).
Although only one number will be shown if the size is the same along
the three axes, three different numbers separated by spaces can be entered.
Clicking **reset** restores the initial values.

**Cell angles** – angle(s) in degrees between
the crystallographic axes

**Rotation axis** and **angle** describe a transformation.
When a data set is created by
resampling,
these fields show its transformation relative to the original data set.

UCSF Resource for Biocomputing, Visualization, and Informatics / July 2019