I had a look at the original question on Stack Exchange and don't think it has been well thought through.
The enquirer states (my interpretation):
1. He has uploaded a GEDCOM from Family Tree Maker/Ancestry to WikiTree containing about 1200 people
2. He has since amended the original Family Tree Maker/Ancestry Database, adding new individuals (and presumably additional source data)
3. He now wants to compare the GEDCOM he originally uploaded to WikiTree with a newly exported Family Tree Maker GEDCOM which contains all the additional individuals/work done.
4. He wants to remove the '1200' individuals already uploaded to WikiTree from the latest GEDCOM copy to avoid duplication/additional re-checking of the information already input.
5. He then wants to upload the supplementary information to be linked to the existing WikiTree file.
There are a number of programs (including FH) that would enable him to compare two GEDCOM files side by side and allow the deletion of duplicate individuals from one of those files, leaving an edited GEDCOM with just the 'new' individuals with their data.
Problems with this (as I see them):
- The new GEDCOM would have no remaining links to the 1200 deleted individuals originally input, so how would they be appended correctly to the existing data in WikiTree.
- What does he intend to do about any new facts/sources added to existing individuals, which would be 'lost' if those individuals were deleted from the GEDCOM to be appended?
- As at September 2017, WikiTree does not directly Import GEDCOMs. GEDCOM uploads have to be run through an online comparison process which requires individuals to be checked and compared one-by-one by the user against the existing data.
https://www.wikitree.com/wiki/Help:GEDCOMpare.
Suggested alternative:
- Use existing desktop software to identify those individuals and additional data (facts/sources) added since the last WikiTree update.
- Export those individuals affected by the changes (including any key linking individuals that will have been in the previous upload to WikiTree) to a new GEDCOM (or to a batch of smaller GEDCOMs). Most applications, including Family Tree Maker can do this.
- Use WikiTree's 'new' GEDCOMpare' method to add the new data/individuals.
Mervyn