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LADOTD - Convert Latitude/Longitude to Routeid or LRSID

Latitude: Longitude:    
Routeid Measure
LRS ID: LRS Logmile:
Type Number Byp/Bus
Control Section CS logmile:
UTM East: UTM North:
Note: LRS ID is CCC-SS-D-SEQ (CCC-SS = control-section, D=Direction, SEQ = sequence)     LRS Help
Year of Data:
Lat/Long Formats:

District/Parish Lat/Lon for Trnsport
Location Latitude Longitude
Revised as of August 2020 (for Routeid/Measure as used in Roads and Highways
[ Engineering Applications | LADOTD Intranet ]         Upload and map a File of Points
      Upload csv file of lat/long to convert to csect/logmile - Get latitude/longitude of a point Upload csv file of csect/logmile to convert to lat/long


This program will convert locations from any one of the following reference systems to the others:
1. latitude/longitude
2. control-section/logmile
3. lrs id/lrs logmile
4. routeid/measure
5. route/milepoint
6. utm zone 15
Which conversion it does depends on the button you press.


Beginning with 2019, the Roads and Highways Routeid and Measure is an option in this program. For 2019 and after, the LADOTD Road maps are primarily organized around the routeid and route measure (distance from the beginning of the routeid).

RouteID refers to one of possibly many roads along a roadway.
It is in this format for state roads: 999_Route_X_Y_ZZZ
-- 999 indicates a state owned road
-- Route is the route name
-- X is the direction (1 = in direction of route, 2 = in opposite direction of route)
-- Y is a specific line within the route:
---- 1=main roadway in direction of route (right side)
---- 2=main roadway in opposite direction of route (left side)
---- 3=frontage road on right side in direction of roadway
---- 4=frontage road on left side in opposite direction of roadway
---- 5=frontage road on right side in opposite direction of roadway
---- 6=frontage road on left side in direction of roadway
---- A to Z - ramps (not defined here)
-- ZZZ - is a 3-digit sequence number

These are some examples of state road routeid's:
-- 999_I-10_1_1_010
-- 999_US 190_2_2_010
-- 999_LA 1 BYPASS_1_1_010

It is in this format for non-state roads: PPP_Street Name_X_Y_ZZZ
-- PPP is the 3-digit fips code for the parish
-- Street Name is the Street Name
-- X, Y, and ZZZ are the same as for state roads

These are some examples of state road routeid's:
-- 001_MAIN ST_1_1_010
-- 003_NORTH BLVD_1_1_010
-- 005_HIGHLAND RD_1_1_010

Measure is the number of miles from the beginning of the Routeid
Road segments will have a MeasureFrom and a Measureto.


Beginning with 2019, route and milepoint will be calculated by using direction 1 of the routeid. Route and milepoint are essentially obsolete after the implementation of Roads and Highways. They are included here for historical purposes.

Control-Section / Logmile

The control-section and logmile are those defined by the LADOTD Control-Section manual. Using control-section is the same as using direction 1 of an lrs_id.

LRS ID / Distance

The LRS ID is described by the document LRS_ID_Procedure.pdf . It is the new way at LADOTD of defining road segments. The distance associated with the LRS ID is in the direction of travel on the road segment. The corresponding control-section/logmile and route/milepoint are those belonging to the main line of the roadway that is closest to the point in question.

Input Formats

The latitude/longitude may be input as:
DD.DDDDD - whole degrees and decimal parts of degrees
DD:MM.MMM - whole degrees, whole minutes and decimal parts of minutes.
DD:MM:SS.SS - whole degrees, whole minutes, and seconds.
If you use the second or third options, you must use a space or a colon(:) as a separator.

Output formats

The output formats are selected by the radio buttons. They are similar to the input formats.

Source of Data

The route and control-section cross-reference data are from the LADOTD Surface-Type Log File.
The latitude/longitude data by control-section logmile was obtained from the LADOTD mapping section in the form of an ESRI geodatabase.
The UTM conversions are calculated.

Converting latitude/longitude to control-section/logmile

The source data set contains a set of line segments no more thatn 0.1 mile long for each control-section. Each segment contains the control-section, beginning logmile, ending logmile, beginning latitude, ending latitude, beginning longitude, and ending longitude. The program finds the line segment segment closest to the target point (based on the latitude and longitude) and draws a perpendicular to that line. The logmile is then calculated.

If the intersection rule is applied, the second closest line segment is found. If it is on another route and meets the intersection rule requirements, that segment is used instead.
Glenn Chustz - LADOTD - April 17, 2002

UTM/DOQQ Revisions - November 11, 2002

Routeid Revisions - August 2020

The UTM coordinates were added as an option. This will convert the data from latitude/longitude to utm zone 15 coordinates in meters. It also creates a link to the DOQQ that contains the location.

The UTM to lat/long conversion calculations in this program were copied from the National Geodetic Survey (NGS) program named UTMS, available from the web site which also has an interactive mode which allows you to do the same calculations.
A useful resource is the NGS Geodetic Toolkit:

This program is in no way intended to replace the Department's GIS tools.