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LADOTD - Convert Latitude/Longitude to Routeid or LRSID
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Revised as of August 2020 (for Routeid/Measure as used in Roads and Highways
Help
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.
Routeid/Measure
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
where
-- 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
where
-- 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.
Route/Milepoint
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
http://www.ngs.noaa.gov/TOOLS/utm.shtml which also has
an interactive mode which allows you to do the same calculations.
A useful resource is the NGS Geodetic Toolkit:
http://www.ngs.noaa.gov/TOOLS/
Disclaimer:
This program is in no way intended to replace the Department's GIS tools.