JOSM zooms out when downloading new data

Every time I download new data in JOSM, (File > Download data, or Ctrl+Shift+Down, and accepting the default selecting which is the current viewport), then the maps zooms out, with the downloaded data only covering the inner 50% of the new viewport. I have to zoom in once to go back to the previous view and the actual extends of the downloaded data.

Also using 5 (Zoom to Download) zooms out too much making the actual download only cover 50%.

Is this due to a combination of wrong settings?

I initially though this was some faulty HiDPI processing, but my screen is only 1920x1080 and set to 100% scaling in Windows.

Using JOSM 14945, jPortable 1.8.0_201, Windows 10.

I think it depends on the background image and some settings like “Zoom to native resolution”

That seems related yes, without background image it still zooms out after a download, but now it’s only about 15%. Where would I find the “Zoom to native resolution” option?

Right click on the background image layer.
Reg. "5 (Zoom to Download) ": I can reproduce that and I agree that it is not correct.

The “Zoom to native resolution” on the right-click menu is an action, not an option. You can’t “check” it, but I guess if you somehow zoomed to a non-native resolution, then this item puts you back to native resolution.

The weird thing is, I can not change my zoom to non-native. Even dragging the zoom bar in the top left of the map, jumps in large steps over what I guess is 100%, 200%, 300%, etc.

In the layers window, I found a little icon of black and white boxes, that says “Scale follows native resolution of this layer”. However, disabling that for every layer, still doesn’t stop the zooming out to double the downloaded area.

Guys, there is a solution.

Under expert settings change value of download.zoomtodata from true to false.

Doing that is the same as disabling “Zoom to downloaded data” in the download window. However, as the name implies, this also means that if you select another area, you won’t get to see the download.

Disabling “Zoom to downloaded data” is really the opposite of what I want. I want it to zoom to the downloaded data, but what it does is zooming to double that area.

I’ve openend a JOSM ticket:

Thanks! This works great in v.14986, IF I turn off “Scale follows native resolution of this layer” every time I add a layer.

Maybe this is a whole new issue, but is it possible to turn off this default “Scale follows native resolution of this layer”? I don’t really see the reason for having this on by default.

Good question. Do you have an example where this option appears?

Forget my question. I see it when I right click on the layer.

I have to play with this to find out if it still makes sense…

Did you try the new preference? If it works for you I’ll add documentation to the wiki.

Sorry, what new preference do you mean? Or do you mean the new zoom functionality? That works great, but I have to turn off “Scale follows native resolution of this layer” every time I add a layer, which I think is a weird requirement. (As well as that this option is difficult to find.)

Reading that bug description (“Resizing uses nearest neighbour algorithm, resulting image is noisy”), I am wondering if they are talking about high-contrast graphic layers. When using aerial photos (which I normally use), there is no noise when the layer is resized, and this locking of the zoom to the layer resolution is of little use.

I am not able to find the “Snap zoom to Mercator zoom levels” setting described in the issue. I would really like a one-time setting where I can disable the locking of zoom to resolution.


Ah, I understand :slight_smile: Downloaded 15017, and tested without and with changing the setting, and the settings sticks after restarting. Looks good!