Genealogica Grafica: errors related to gedcom inconsistencies
|13 Nov 2010
|Covered in this document:
Covered in related documents:
A Gedcom file records the family structure in a standard format. This standard
is maintained by The Church of Jesus Christ of Latter-day Saints (LDS) (see
here for details).
Apart from header and trailer, the file consists of records for individuals (INDI records) and for relationships (FAM records). Each such record is uniquely named with an identifier. For INDI's this is mostly a number preceded by I (capital i) and FAM records normally get an F prefix for a unique number. These identifiers are only meaningful within the gedcom. They are necessary to link INDI's to FAM's and vice versa.
INDI records contain details of individuals, such as their name, place and date of birth and death, and occupation. There can also be references to FAM records, for instance to indicate the family from which the person was born. For such a reference, the FAM identifier is used.
FAM records contain the details of a relationship (typically: a marriage), such as place and dates. And of course the individuals who play a role. There can be a HUSBand and a WIFE and a number of CHILdren. These are all referenced by their own ID.
With this way of relating INDI's to FAM's and vice versa, it is feasible to record birth from one family and adoption from another, dual marriages, unknown parents (HUSB or WIFE missing in the FAM record), etc.
In the example below John Smith married Mary Green and they got a son Jacob Smith.
0 @I001@ INDI
The FAMS reference for John and Mary indicate that they are partner in FAM F01. For Jacob, the FAMC reference indicates that he is a child in F01.
Nb: in a real gedcom there will be no blank lines. The numbers preceding each line indicate a data structure: a higher number says this is a detail of the previous data (eg the birth data of John).
Possible gedcom inconsistencies
The references between INDI and FAM records can lead to inconsistencies. For
instance: what to do if John Smith with SEX = Male shows up in FAM F01 as WIFE ?
Such an error does not occur very often, but the following do:
Genealogica Grafica verifies that such inconsistencies do not occur, since they may frustrate the calculations. The corresponding errors are explained below and how to cope with them is described further down.
The source of these errors is in your genealogical program that produced the gedcom. Most likely they are the result of changes you made over time, such as deleting a person. Clearly, the program should also delete that person from any marriage he/she was involved in. But sometimes this goes wrong.
Another source of error that we've seen is a corruption of the gedcom itself. If for instance an End-of-line character is missing then the next line will not be read. If this line is the start of an INDI or FAM record, that person or family is lost and its data is seen as part of the current record. Such errors may result from improper handling of special characters by your program and from (data) transmission errors. You can only find them by analysis of the gedcom file.
There is another kind of inconsistency, namely that someone is his own descendant (result of assigning an ancestor when entering a child). This is a so-called 'loop'. When you trace ancestors or descendants from this person, you will find a path that continues indefinitely since you will encounter the person itself and then move on. Loops are notoriously hard to detect but Genealogica Grafica will do it for you. And it will also pinpoint which links in the loop are suspect.
Also, there may be duplicate entries in your gedcom. A situation to be avoided at all times. In order to find these, we notice that two records of the same person can not be linked via family relationships. Hence, if present, the gedcom must contain isolated groups of persons. These may form small families, but none of its members connect to the main body of the gedcom. Genealogica Grafica will list these groups and then scan them for duplication of individuals.
We check various date relationships in order to assist you in locating link errors and data entry errors:
Some of these checks are straightforward. Checking that death is after birth,
for instance, can be done on individual INDI records. Other tests are more
involved. To verify that a mother was older than (say) 15 before she got her
first child, you need to correlate the records for mother, her fam relationships
and all the children.
Genealogica Grafica does not stop there. It will 'reason' about all the available dates in relation to each other. This algorithm, akin to Artificial Intelligence, can indicate inconsistencies accross generations - in particular when dates have not been recorded. Comsider for instance the case where birth dates of mother and grand-child are 20 years apart, while the birth date of the daughter is not known. Genealogica Grafica will draw your attention to this situation, since there is most likely a recording error.
What to do with errors
You will need to correct gedcom consistency errors. They can corrupt the
Genealogica Grafica outputs. Beware that in many cases they also compromise the results of
your own genealogical program. Genealogica Grafica will remove inconsistent links for you,
but this may result in the loss of an essential family relationship.
Some of the errors may be hard to locate. Since each genealogical program has
its own user interface, there is no standard approach. Typically, you would find
the person involved, check the family links and then add or remove marriage or
To assist you in this correction process, a file is produced with details of the
errors reported (see example). This file is named 'GedcomErrors.HTM' and should be found in
the directory from where your gedcom is read or where you save your settings.
From within Genealogica Grafica you can inspect this file via 'Windows - Gedcom Errors'. The links then bring you to the actual records in the gedcom, so that you can check at the source. And the 'Nearby Family' display and various search options will ease the process of pinpointing what's wrong. Some corrections can be made in Genealogica Grafica via the edit menu in the gedcom view window. You can change dates, places, names, notes, etc; but you can not change IDs, links or order of records. For that you should return to your registration program (which can be open at the same time).