CENtaR is as a free web service. CENtaR uses the same GEDCOM Parser that is used by VGedX Online, my 100% compatible GEDCOM validator. CENtaR, however, supports a special expanded GEDCOM dictionary that will recognize numerous vendor specific events and date formats.
CENtaR includes in its report the Id and name of each person included, the Census years considered, and one of 4 codes for each entry: '-' (not applicable), 'm' (missing), '?' (unknown location), 'XXX' (location), where the location code uses ISO standard codes when possible for identifying places to the "state" level. Further, hovering your mouse over an entry will display source information, if available.
CENtaR also uses the same algorithms used by Vivify, the GEDCOM Birth Date Estimator to calculate accurate and reliable missing birth dates so that each individual considered will only be included if it is determined that they were likely to be living during the specific Census years.
I first introduced the concept of the Census Table Report on my blog in the article Making CENS of it All, but I have been using and publishing my own census tables online for over a decade. I find Census Table Reports to be one of the most useful concepts for identifying areas of needed research. They provide several other benefits as well, such as the ability to see migration patterns and identify those direct ancestors living during the period in which census records were being taken.
In addition, CENtaR supports detecting "Not Applicable" Census records. When a "Not Applicable" Census record is detected, the Census Table Report will be updated to reflect it by changing the missing identifier to the not applicable one. When all years are not applicable, the person will no longer appear in the table. Users can include the text "[Not Applicable]" in any field of the GEDCOM
CENSus record to indicate this, except the
DATE field as that is the key field identifying the Census year that needs to be ignored. I personally use the
CAUSe field, but other fields could be used as well, such as
NOTE. Indicating that a year is "Not Applicable" to a particular person is an strategy that can be used to clean out invalid entries from the Census Table Report.
It should be noted that CENtaR relies on detecting the GEDCOM
CENSus field in your database. Some vendors, unfortunately, do not use this standard GEDCOM tag when adding census records to your database, resulting in CENtaR not being able to match any dates with individuals.