Is it possible to preserve explored map progress when deleting chunks from the savefile?

[Fred84]

As the upload size is limited to 500mb, and my local savefile was beyond 2gb, I had to delete chunks with MCAselector.

Now, we like to explore and make map walls, and here we had a giant 6-by-10 level 3 map wall.

After deleting the chunks, opening the world locally has no effect on the maps, but if I upload the savefile, the maps are either missing or corrupted.

I tried re-uploading the map_###.dat files, but it did not really solve the problem.

Is there a way to preserve those map walls or should I give up and be ready to re-explore everything?

[Fred84]

ok, I solved it.

actions I followed:

• create new temporary default world
• delete old upload
• log in new temporary world to prevent hibernation while I do the following
• upload savefile again
• navigate to the data folder where all the map_###.dat files are
• re-upload these files
• re-set the new uploaded world to be the default
• delete the temporary one

 

[_omga]

I wouldn’t think it is possible to preserve the map data as map data is stored directly in the world and not on item data. 

[Fred84]

13 minutes ago, _omga said:

I wouldn’t think it is possible to preserve the map data as map data is stored directly in the world and not on item data. 

with "directly in the world" what do you mean? in the .mca files? then what's in the map_###.dat files?

[_omga]

Well, I don’t know much about maps and how they are stored. Assuming the map .dat files take data directly from the world files, I would think you wouldn’t be able to. 

[Fred84]

according to the wiki, no:

https://minecraft.gamepedia.com/Java_Edition_level_format

Quote

/data/map_<#>.dat

Map item format

Stores the map data for the craftable Map items.

and from https://minecraft.gamepedia.com/Map_item_format#map_.3C.23.3E.dat_format

Quote

colors: Width * Height array of color values (16384 entries for a default 128×128 map).

I understand that the maps should be preserved, because the color arrays are unchanged until I reload them (hold them in my hand)

 

[_omga]

I see, well, then I’m afraid I am no help. Sorry.