Mike is correct, of course, but he is thinking of performing the merge in the standard way which can be used for any record type, by selecting the records to be emerged in the Records window then using Edit>Merge/Compare Records. On the other hand I was thinking of Using Tools>Work with Data>Places, where you can select the records to be merged and then click the Merge button. In that case you only get to choose one whole record for the final version, and you cannot ‘pick and choose’ which parts are retained. So if you do it that way the final record will have whatever geocoding was in the record you selected for the final version, even if it had none and one of the other records did have geocoding.
The principles of merging any type of record are fundamentally the same, but depend on several factors.
If a particular field is allowed multiple instances, such as Notes or linked Media, then the Merge keeps all instances from both records.
If a particular field is only allowed one instance, such as Lat/Long geocoding, then the Merge applies some simple rules.
When only one of the two records has a value in that field, or the value in both records is the same, then that value is kept in the merged record.
It is only when both records have a different value in that field that a decision is needed.
Whichever record is chosen as the final or preferred record then its field value is kept by default, but that can be reversed in the Merge Record dialogue.
So when Lorna says for the final merged record the geocoding in that record will remain unchanged is not strictly correct.
If the preferred final record has no geocoding, but the other record does, then that other geocoding will be used by default, but can be manually overridden.
When you merge two Place records you choose which one is to be the final merged record, and the geocoding in that record will remain unchanged. When you edit the name of a record the geocoding remains unchanged. If you then want to refresh the automatic geocoding, select the record(s) in the Records window and click Map>Map Location of Selected Place Records (or use Tools>Work with Data> Places, select them there then click View in Map>View in Map Window.) Then, in the Map Window toolbar use Map>Geocoding>Refresh Geocoding.
By the way, in order to avoid accidentally refreshing the geocoding for a Place you have previously geocoded manually, it is recommended that you use Tools>Preferences>Map Window and set Mark Auto-geocodes as Tentative if... to Always, and tick Block Refresh for Non-tentative Geocodes.
....I just want to check that if I edit or merge places does the geocoding for latitude etc adjust automatically or is there something I need to do to "recode" the list? I only ask because the conversation above shows me that the mapping function is perhaps more complicated than I might have thought?