Learn About Redistricting
Reapportionment (re·ap·por·tion·ment) is the redistribution of representation in a legislative body, especially the periodic reallotment of U.S. congressional seats according to changes in the census figures as required by the Constitution.
Reapportionment applies to any "local governing authority, including but not limited to any police jury, city or parish council, or school board which is required under the constitution or laws of this state or of the United States to reapportion its voting districts following each decennial census." (La. R.S. 18:1921) 
Louisiana law La. R.S. 33:1411 provides a mandatory six month timeframe after the official release of the census for all parish governing authorities which provide for the election of its members from wards, districts, or other subdivisions to examine the apportionment plan of its body to determine if there exists any substantial variation in the representation of the election districts and then adopt an ordinance by a majority of its members to either (1) declare its apportionment to be equitable and continue its existing apportionment plan or (2) provide for a new apportionment plan. The law further provides that the boundaries of any election district for a new apportionment plan shall contain whole election precincts established by the parish governing authority under La. R.S. 18:532 or La. R.S. 18:532.1 (La. R.S. 33:1411(C)), unless certain exceptions apply. Additionally, municipalities who are elected by districts, school boards, and city councils shall each examine their respective voting districts under their current apportionment plan to determine whether or not there is a substantial variation. At that time, they will adopt an ordinance either confirming their voting districts are equitable or providing a new plan.
If it is determined that a new plan is needed, the governing body will then meet to discuss possible changes to the voting districts. At this time, some do elect to bring in outside demographers to assist with creating the plan.
When Redistricting Occurs
"Unless a different period of time is specified by the constitution or by statute, the governing authority of each local governing body shall reapportion its voting districts by the end of the year following the year in which the population of this state is reported to the president of the United States for each decennial census." La. R.S. 18:1922
Failure to Reapportion has Penalties
La. R.S. 18:1922 and La. R.S. 18:1923 provide that failure to meet the time for reapportionment by local governing bodies is misfeasance in office and may subject the governing authority to a loss of state revenue sharing funds.
Implementation of Reapportionment Plans by the Secretary of State's Office
The Louisiana secretary of state is responsible for establishing a state voter registration computer system for the registration of voters throughout the state, which contains the election jurisdiction for all offices voted on throughout the state. Redistricting plans are required to be submitted to the Secretary of State's Office by certified mail and to also be sent to the clerk of court and the registrar of voters. La. R.S. 18:1945(C) provides that no redistricting plan shall be implemented unless the plan is received by the secretary of state prior to 4:30 p.m. four weeks prior to the date the qualifying period opens.
If a local government utilizes a geographic information system (GIS) software to develop its redistricting plans, they are required to submit an electronic shapefile to the secretary of state within 10 business days of adoption of the redistricting plan. If they are unable to submit an electronic shapefile, they must submit an ASCII comma delimited block equivalency import file which indicates the census block assignments in the redistricting plan.