You would have to download the area (or parts of it at at time) into JOSM and then manually delete the duplicate data.

Or, if you want I could simply revert the whole changeset in which you uploaded the duplicate data, and then you could go through your improvements offline and add them piece by piece. You will always have to download the data that exists in an area (in JOSM) and then apply your edits and upload again; you cannot (as you seem to have tried here) make a copy of the whole data set and then replace the existing data with your (modified) copy.

It appears you have imported a new road over an already existing road here osm.org/way/476144200#map=18/49.12053/-70.11346&layers=D and tagged the new road with "lanes=-1"?

Importing Canvec data requires some diligence. You cannot just take a Canvec tile and dump it into OSM (else others would have done it long ago). You need to compare Canvec data to existing data or even aerial imagery to make sure you're not making the map worse. See for example osm.org/way/476144472 where you have imported a patch of green landcover that sits completely beside the island in Lac Carrier where it belongs - either you need to fix the landcover or the island. Same for almost all the forest you imported bordering Lac Carrier; being of a much inferior resolution compared to the lake itself, the woodland cuts into and out of the lake at random. Please don't insult Canadians by calling this kind of mapping a "patriotic duty", and try to place quality over quantity in the future.

Oh dear, this changeset and the few others you uploaded at the same time have actually *duplicated* almost all the data in the city - now your new data sits on top of the unchanged old data. I think we should remove your new data again, to give you a chance to properly conflate your changes with the existing data. Or what would you suggest?

Hello, in this changeset you deleted y couple of buildings and your comment says that you deleted them because they are in a security area. However, OSM does not generally respect specific national security interests with regards to mapping. If a building is visible on aerial imagery, then it may be mapped in OSM, no matter whether it is in a security area or not. Deleting such a building, as you have done here, can be interpreted as an act of vandalism on OSM. Please don't do that.

Wie hast Du entschieden, welche Objekte ein "beacon:type=vor-dme" bekommen? Hast Du hierzu eine externe Quelle verwendet, oder Dich rein auf existierende OSM-Tags verlassen? Hast Du jedes einzelne Objekt bei OSM angeschaut, das Du bearbeitet hast? Hast Du diesen mechanischen Edit vorher mit der Community diskutiert?

Hello HourOfTheWulf, it is interesting how you're adding 9 playgrounds across all of Holland. Have you recently been on a nationwide playground survey trip, or what is the source of this data?

I have reverted my deletions. I still believe it's wrong to map time zones, and all time zone boundaries in OSM should be deleted, but I agree it was premature to delete them nilly-willy. I will bring this matter up for discussion on the tagging mailing list. Please join me there.

Admin boundaries and maybe sometimes post code boundaries are the big exceptions; their presence in OSM doesn't mean that we can now map any kind of boundaries that are not visible or verifiable on the ground! This just doesn't scale - we can't add all boundaries that someone might find interesting to OSM, we must rely on those boundaries being defined outside of OSM in terms that can be matched to OSM ("these states/counties have this time zone"). In which area did your time zone boundary not follow an administrative boundary, and which external source did you get the definition from in that case?

Hello Fredie, of course if you map new things then you get to decide how you map them; a large landuse area for a whole village or smaller areas - no problem. But you should not delete the work that others have done and replace it with "your style". Also, your changeset deletes a large number of other objects e.g. tracks - but big edits like this should be explained in the changeset comment. What did you do, why did you delete so much - that explanation belongs in the changeset comment and not "reg. Oltreponte C.Popolo (AL/PIE/IT)" which does not explain your actions sufficiently.

Hallo, kann es sein, dass hier ein Missverständnis vorliegt? Die Grünfläche, um die es hier geht - private Gärten im Dreieck Noyon-Allee/Emil-Mörsch-Weg/Herbstweg - ist (a) weder ein Park, (b) noch auf anderen Karten als Grünfläche markiert, (c) noch auf dem Gelände der Kirche St. Bonifatius. karottenjunge1, kann es sein, dass Du Dich einfach in der Straßenkreuzung geirrt hast, und in Wahrheit den (tatsächlich existierenden) Garten von St. Bonifatius 200m weiter südlich eintragen wolltest?

Please explain why this was downgraded from service road to footpath?

Hello, why did you change 115th avenue into a footway? It looks like a normal residential road to me. Please explain.

Hello, could you explain the reason for deleting these roads, and your other deletions nearby? Your changeset comment is "Modifications", but this doesn't say why you thought these roads should be removed.

(automatic translation follows)

مرحبا، هل يمكن أن تفسر سبب حذف هذه الطرق، وغيرها من الحذف الخاص بك يوجد بالقرب منها؟ تعليقك "تعديل"، ولكن هذا لا يقول لماذا قمت بإزالة الطرق.

Du hast bei diesem Changeset als Quelle "Google" angegeben. Es ist uns leider nicht erlaubt, Daten aus Google in OpenStreetMap zu übernehmen. Kannst Du erklären, was Du mit "Google" als Quelle gemeint hast?

Hello SHARCRASH, please consider using different changeset comments. "See the history of the elements from the according changeset." is without meaning, as checking the history of elements is exactly what one has to do if the changeset comment is missing! Nobody expects you to write a novel, but a simple sentence explaining what and why would be extremely helpful to the others working with you in this project. See also: osm.wiki/Good_changeset_comments

Hello Stephen214, in this changeset you seem to have deleted a large number of "mini roundabouts". Can you explain the reasoning behind this? Have you actually looked at the objects in question, or have you simply removed them according to some search/replace logic? Looking, for example, at osm.org/node/2330188058 on the aerial imagery tells me it doesn't look like the normal intersection you made this into?

Hello richardsonp, in this changeset and a couple others you claim to have traced thousands of buildings from Bing imagery. Many of the buildings you have added have much more detail than can be seen on Bing though, e.g. osm.org/way/381251369 or osm.org/way/381251884. I would be interested to hear if you have imported this data from another data source (and if so, whether you were aware that we have rules to govern data imports), or if maybe you have used a different imagery source that allows this kind of precise tracing?

OpenStreetMap maps facts not fiction. Please provide evidence for the existence of this place, or if your edits were meant to be funny, please remove them from OpenStreetMap again. There are other projects like opengeofiction.net that are dedicated to drawing fictional maps; OSM is about reality!

LogicalViolinist, there is no way anyone would trace the building in http://imgur.com/a/9zU2K from the imagery in that picture. Neither Bing nor Mapbox nor whatever is in that picture has the detail to trace that outline. Not even a combination of all of them. -- And the only thing you have to say in your defense is "stop wasting my time" and then Denis comes in and tries to silence criticism by pointing to his superior edit numbers? What is going on here?