Univiewer is a visualisation program for HEALPix maps. It is written in C++ and uses OpenGL and the wxWidgets library for cross-platform portability. Using it you can:
- Rotate and zoom maps on the sphere in 3D;
- Create high-resolution views of square patches of the map;
- Change maximum and minimum values of the colourmap interactively;
- Calculate the power spectrum of the full-sky map or a patch;
- Display any column of a HEALPix map FITS file on the sphere.
Since Univiewer uses OpenGL for 3D graphics, its performance is dependent your video card. It has been tested successfully on computers with as little as 8Mb video memory, but it is recommended to have at least 32Mb to get good performance.
In the 3D view, a HEALPix map is projected onto a ECP pixelation to create a texture which is wrapped around the sphere. In calculating the power spectrum, the spherical harmonic transforms are computed using the same ECP pixelation. This inevitably leads to some discrepancies at small scales due to repixelation effects, but they are reasonably small.