The cameras are very different in technology and design, so the basic answer is "it depends". There are two fundamental differences.... maybe three. Let's call it three:
- Your Canon 1000D is an interchangeable lens camera. You may only have one lens (and if so, probably a 18-55mm "kit zoom"), but you have the option of adding literally hundreds of other lenses made by Canon or third parties. The Panasonic FZ1000, though, has a fixed lens that you can't change.
- Your Canon camera has a bigger sensor — about 3× the surface area. This means more light-gathering ability, and potentially less depth of field (the out of focus areas will be more blurry) — but this depends on the lens.
- The Panasonic camera has an electronic viewfinder — a small LCD screen you put your eye to — while the Canon camera uses a pentamirror to direct light from the lens to your eye. Some people really prefer the direct view, but it's worth noting that the Canon pentamirror is kind of small and dark and the Panasonic's EVF is state-of-the-art.
Plus, it's worth considering that the 1000D is pretty old — very old in technology years. That's particularly going to make a difference in responsiveness and in low-light performance. And as @inkista points out, the FZ1000 will shoot HD and even 4k video, whereas the older Canon DSLR doesn't do video at all.
The FZ1000 happens to come with a rather nice lens. It has a high zoom range, which inevitably means some compromise in pure image quality, but with a lot of flexibility, and it has a decently-fast f/2.8-f/4 maximum aperture range.
Overall, I'd say that you have two main courses for upgrade. If you're interested in getting into the world of interchangeable lenses, swapping different choices for different situations, you might want to start by adding another lens to your existing camera and building up from there. Even an older SLR will have advantages if you pair it with quality lenses specifically chosen for landscape, macro, portrait, and so on, and if you then upgrade to another Canon DSLR body, you could keep that collection to use with the new one.
On the other hand, if you really just want to have one lens, and the one built into the Panasonic works for you, that probably is an upgrade. The difference in seven years of technological progress shouldn't be underestimated, and if you just have the kit lens and no plans of buying another, you're not really taking advantage of having an interchangeable lens camera anyway.