Remove small white spaces between objects

Question

Take this image: https://cloud.iacchi.casa/s/ZbM5NzYLNiA2nMN most of which is made from concentric rings or adjacent lines. If you open it in inkscape you can already see white spaces between the different objects. In Illustrator you don't really see it, but in both cases when you save it as pdf (which is what I'll need to do ultimately) you get this (again, the size of the white gap changes between pdf viewers):

In my mind, to remove this problem an easy way is to add a thin outline to each object, and assign it the same colour of the filling. However, doing this for each object is going to take forever (I also have several similar images to manipulate). So I ask: is there a way in Inkscape, Illustrator, or other free vector graphic programs to select all objects, and tell the program to add an outline (is it called stroke in technical terms maybe?) to each object and assign to it the colour of the object's filling (different for each object)? And if this is not the best way to proceed, which is?

Answer 1

The problem is caused by vector shapes butting up against each other, a kind of conflation artefact caused by anti-aliasing, and it's a very common problem when rendering vector images - especially in browsers.

In Illustrator you could try using an Offset path effect, just a very small amount, to create a very slight overlap of the shapes, then Expand the Appearance before exporting as SVG.

Example (before expanding appearance).

See SVG after expanding appearance