To maintain device independence, GDI creates output in a logical space and maps it to the display. The mapping mode defines the relationship between units in the logical space and pixels on a device.
There are eight different GDI mapping modes, each of which has a specific use in a Windows application. Following are these mapping modes:
| Mapping mode | Description |
| MM_ANISOTROPIC | Maps one logical unit to an arbitrary physical unit. The x-axis and y-axis are arbitrarily scaled. |
| MM_HIENGLISH | Maps one logical unit to 0.001 inch. The positive y-axis extends upward. |
| MM_HIMETRIC | Maps one logical unit to 0.01 millimeter. The positive y-axis extends upward. |
| MM_ISOTROPIC | Maps one logical unit to an arbitrary physical unit. One unit along the x-axis is always equal to one unit along the y-axis. |
| MM_LOENGLISH | Maps one logical unit to 0.01 inch. The positive y-axis extends upward. |
| MM_LOMETRIC | Maps one logical unit to 0.1 millimeter. The positive y-axis extends upward. |
| MM_TEXT | Maps one logical unit to one pixel. The positive y-axis extends downward. |
| MM_TWIPS | Maps one logical unit to 1/1440 inch (1/20 of a point; a point is 1/72 inch). The positive y-axis extends upward. |