Images (on which ImageView is based) has an ImageCmap (= "image colormap") type. You could play with it and see how far you get.
Also, see the "MapInfo" section of http://timholy.github.io/Images.jl/function_reference.html. It's a crazy- powerful mechanism for on-the-fly changes in how data are mapped to screen pixels. --Tim On Thursday, August 13, 2015 05:44:16 AM Maurizio Tomasi wrote: > Hi to everybody, > > I am the creator of Healpix.jl, a Julia > package (https://github.com/ziotom78/Healpix.jl) which implements > algorithms related to the Healpix sphere tessellation scheme > (http://healpix.jpl.nasa.gov/). The Healpix scheme subdivides a sphere in > patches (pixels) of equal area, and it is widely used in cosmology. I am > writing to julia-user because I would like to implement visualization > functions too, but I haven't figured out what is the best way to implement > them. > > So far, I have used the Healpy (https://github.com/healpy/healpy) library > as a reference for my implementation. Healpy wraps the original C++ Healpix > library in a Python module. It uses Matplotlib to create plots of spherical > projections. Internally, both the original C++ Healpix library and Healpy > produce such plots by calculating a bitmapped representation of the > projection: they convert each (x,y) point in the image plane into a > normalized (u,v) coordinate, which is then spherically projected to a point > on the sphere's surface. The value associated to the point on the sphere > determines the color of the point at (x,y). Here are a few examples of > typical Healpix maps: http://healpix.jpl.nasa.gov/images/skymaps/ecl53s.gif > (Mollweide > projection), http://healpix.sourceforge.net/html/plot_orthpolrot.png > (Orthogonal projection). > > The algorithm is really easy to implement in Julia, but I cannot decide how > to actually do the following: > > 1. How to interactively show the map by e.g. opening a window, or by > displaying the image directly in a IJulia notebook? > 2. The bitmap produced using this algorithm associates a scalar to each > pixel, but one usually wants to convert such scalar through a color map in > order to have a RGB value to be actually drawable. (I am interested in > piecewise-linear maps). > 3. When displaying the map, how to put a color bar under the map, like in > the two links I provided above? > > I have had a look at ImageView, and it look ok for point 1. However, it > seems to me that it is oriented towards "real" image files, because I > cannot find support for color maps and color bars. If it is really so, is > there any other Julia package which would be relevant for my purposes? > > Thanks a lot, > Maurizio.
