> For the complete documentation index, see [llms.txt](https://docs.phoenixlidar.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.phoenixlidar.com/spatialexplorer-8-and-9/user-interface/toolbars/analytics/measure/surface-area-and-point-density.md).
# Surface Area and Point Density
Point density and surface area can be computed using this option. First, specify the cloudgroup and polygon geometry. Then, specify the grid stride used to create the TIN mesh:
Point density values are reported in both planar and surface values:
**Density Projected Plane** refers to the point density over a flat plane. **Point Density Surface** refers to the point density over the TIN surface. When terrain is hummocky or uneven, the point density over the surface will be noticeably lower than the density over a projected plane, because the surface area of the mesh is larger than the surface area of the basic, projected plane.
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