[PATCH] WMSPlugin can't request arbitrary large areas from WMS servers when selecting "Download visible tiles"

[avarab@…]

When I select "Download visible tiles" when using WMS WMSPlugin will sometimes refuse to do so with the error message "The requested area is too big. Please zoom in a little, or change resolution".

Instead the software should do what I told it to do.

This patch introduces a preference which can be set in the Einsten dialog to ignore the warning, but perhaps the dialog box should be modified to allow the user to bypass it instead?.

[avarab@…]

Patch to WMSLayer.java for adding the wmsplugin.maxarea-error.ignore preference option

[stoecker]

Refused. This option is to protect servers from useless large traffic. Adding such a setting would make this protection useless and also be fatal for autoloading.

[avarab@…]

Then do you mind if I fork wmsplugin and upload wmsplugin_nonanny (or something) to SVN extensions so I can use that instead? It's easier than maintaining my own build system.

If users are going to hammer public servers they can do that with or without JOSM's help, and this limitation is particularly annoying when the WMS server I'm connecting to happens to be mine and because of this limitation I have to do a lot of redundant zooming/panning around instead of just telling JOSM to request all the tiles and wait for them to load.

[stoecker]

Why do you want to do that anyway? If you want to load large areas then use a lower resolution. You have a menu point "change resolution" to do that.

What you request is loading very large areas in high resolutions which will then probably be dropped anyway due to cache limitations.

I do not care what people do to servers with whatever software they use, as this is their problem. But if JOSM is doing it, then all users are affected and one useragent-block will effectively kill all JOSM users from using that servers. And JOSM is the only thing which the server operator will see.

[avarab@…]

Replying to stoecker:

Why do you want to do that anyway? If you want to load large areas then use a lower resolution. You have a menu point "change resolution" to do that.

I explicitly want to load a large area at high resolution. What I'm doing is tracing say a 1000m x 1000m area on a aerial map with ~1-2 meter resolution. So I'll zoom into a 50m x 50m box, turn on WMS, then zoom out again to 1000m x 1000m, select "Download visible tiles", wait for it to load, and then I can trace that 1000m x 1000m area without a network connection.

In theory anyway.

What you request is loading very large areas in high resolutions which will then probably be dropped anyway due to cache limitations.

Do you mean the behavior of WMSPlugin to only keep a set number of images visible at any given time? Yeah that's somewhat of an impediment, and I've been looking for a way to disable it so that I can just delete the WMS layer and start again if JOSM starts using too much memory - and rely on the cache when I render the area again. But even when I have to deal with that the whole process is much easier when "Download visible tiles" works like I want it to.

I do not care what people do to servers with whatever software they use, as this is their problem. But if JOSM is doing it, then all users are affected and one useragent-block will effectively kill all JOSM users from using that servers. And JOSM is the only thing which the server operator will see.

I'll just maintain my patched version locally then.

[stoecker]

Maybe if you change the patch so, that your hidden setting causes opening a popup telling you "This request will cause xxx individual requests at the WMS server causing large server load. Are you sure you want to do that?" it can be included. The text should make clear that this is a BAD thing to do.

Regarding the cache: You can increase it. Search for cache in einstein.

[avarab@…]

Replying to stoecker:

Maybe if you change the patch so, that your hidden setting causes opening a popup telling you "This request will cause xxx individual requests at the WMS server causing large server load. Are you sure you want to do that?" it can be included. The text should make clear that this is a BAD thing to do.

I'll see about doing that. But being lazy I thought an undocumented option might do initially :)

Regarding the cache: You can increase it. Search for cache in einstein.

Do you mean cache.wmsplugin.expire and cache.wmsplugin.maxsize? That's all I find under cache. That's the on-disk cache, but I'm talking about the on-screen cache, I.e. when I use WMSPlugin long enough to pan around it'll start deleting old tiles from my map view, although they aren't being deleted from disk due to my cache policy.