On 24/05/13 04:31, Mark Durre wrote:
(1) Fits Import & WCS. As a follow-up to Christian Ambrose's query on fits file imports, I would find it useful to have a function, either on the import step or later, to reset the WCS header data on 2d datasets, I.e. Set the CRPIX1/2, CRVAL1/2 and CDELT1/2 values to 1. This means that each pixel co-ordinates is just the matrix position. This would obviously be useful mainly for data that has square pixels.
This would be fairly easy.
(2) Expanding operations to include 2D datasets. As far as I can see, Operations only happen on 1d datasets, is this correct? If so, I would like to be able to expand this to 2D dataset where appropriate. For example, I would like to be able to filter images to mask out low values, setting them to Nan, so they are not plotted. You can do this with Transparent data, but it's a pain. You would probably need a generic value name for the data for the filter function, e.g. '($DATA<10)'
They are all limited to 1d currently, which would be nice to change. At the moment the operations need to know the type of the dataset (1d or 2d). It would be good to remove this requirement if possible.
You can, however, do operations on 2D datasets via the Create 2D dataset dialog box. Select "From expression based on existing 2D dataset. You can then enter a expression like my2d - 1 or where(my2d>=2, my2d, nan). This requires knowing the numpy syntax, however.
(3) Graph Axis Sizes. At the moment, the size of the plotting area is controlled by the page size less the margins, in both directions - this can be a computational pain. It would be good to be able to set the axis lengths absolutely, especially for 2–d plotting of square pixels where the matrix dimensions are not the same. I would presume that the margins would then be recomputed automatically.
This is a bit of a problem, because it is quite convenient to be able to resize the page, but have the graph fill most of the page - that's why it is margin-based. It's also margin-based because the model is that widgets are contained inside widgets. If it's size-based it would need an origin and a size. Things like putting graphs inside grids would be difficult with absolute graph sizes.
It's probably possible to add an option to switch between size and margin modes, though this would make the code rather complex.
A different, perhaps better, option to achieve fixed pixel sizes would be a fix aspect ratio option, which would make the largest graph with that aspect ratio (e.g. 1:1) inside the margin area.
Jeremy _______________________________________________ Veusz-discuss mailing list Veusz-discuss@gna.org https://mail.gna.org/listinfo/veusz-discuss
