Linear Referencing for DOT using ArcMap ?

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04-05-2017 01:12 PM
RaymondArotin1
New Contributor II

Hello,

I work for the Department of Transportation in Pennsylvania.  I was surprised, when I came to PennDOT that the majority of the GIS users were unfamiliar with ArcMap.  Mostly they use GeoMedia and other "in-house" programs (Maintenance IQ) that work very well with Linear Referencing.  These programs integrate with the supervisor's databases and spreadsheets and connect to maps quickly and relatively easily.  PennDOT uses Line Segments, and segment offsets (both at the beginning of the segment and another offset at the end, to... say, establish a Roadwork route, such as paving or shoulder cutting).

There doesn't seem to be a fast and easy way to take a spreadsheet with these segments and offsets and integrate it into a map in ArcMap with State Roads shapefiles.  The "Make Route Event Layer" in ArcTools doesn't have enough options to make a route correctly based on the Beginning Offset and End Offset.  It won't accept the State Route Number as an acceptable field as the "Route identifier" field.  Then, it is impossible to choose the Seg_Beg as the "from" and the Seg_End as the "to".  Furthermore, it doesn't have option for two separate Offsets.

I'm not very familiar with Linear Referencing, so perhaps I'm going about it wrong.  In my past job, I used x,y coordinates exclusively.  Not sure if anyone can help or point me in the right direction.  I really can't get into a huge, complex solution however.  If it's not simple and quick, it won't happen.  (3rd party software?  Work around?)

9 Replies
TedKowal
Occasional Contributor III

This may help you understand the basics of ArcGIS linear referencing. What is linear referencing?—Help | ArcGIS for Desktop 

Penndot, if memory serves correctly, uses a Quadrant system in tangent to a linear referencing line.  

You may want to contact some of these folks who wrote article....

PennDOT Integrates ArcGIS for Modernized Field Data Collection 

Ted

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by Anonymous User
Not applicable

Hello Raymond. I think there should be a relatively simple way to translate between offset system that you use at PennDOT and a standard ArcGIS Route system. Would you be willing to share some of your route and event data? I'd be willing to take a look at it and see if a simple translation is possible.

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RaymondArotin1
New Contributor II

Tom,

Thank you very much for reaching out to me. I would appreciate any tutorial guidance or insight on this that you can provide.

 

I uploaded three shapefiles which are all you need to create a simple map of Jefferson County, Pennsylvania.

  1. PaCounty2015_01 – these are polygons of all the counties in PA.
  2. Jefferson_Municipalities – polygons of all the Municipalities in Jefferson County
  3. RMSSEG_Roads_Jefferson_County_PA – Polylines of all the State Roads in Jefferson County

 

The RMSSEG Roads shapefile is a “stripped down” version. Usually it has many, many columns with various information about Lane Counts, Pavement conditions, and more.  But none of that is relevant to this discussion, so I took those out and kept the shapefile as basic as possible.

 

The most important Fields are these…

ST_RT_NO – The State Route Number. (Route 536, Route 1012, etc.)

SEG_NO – Each State road is divided into Segments.  Not all segments are the same length.  They are usually numbered as such: Seg 0010, 0020, 0030, etc.

SEG_LNGTH_ - This is the length in feet of each segment.

CUM_OFFSET – This is basically the cumulative feet at the beginning of each segment.  So the first segment would say “0”.  The next segment might begin at “3725” feet.

CUM_OFFS_1 – This is the cumulative feet at the end of each segment.  So, the first segment would say “3725” feet, if the entire first segment is 3725 feet.  The 2nd segment might say “7011”.  So that would be 3725 + 3286 (the cumulative feet of the first segment plus the cumulative feet of the second segment).

 

Event Table.

I also uploaded an Excel spreadsheet with 3 “events”. (An Event table).

 

I kept this very simple. I made 3 events.  So this is how a Supervisor would normally show where an Event is happening.  (Usually the spreadsheets are much more complex with lots and lots of data such as material, crews, payroll info, equipment numbers, etc…. but none of that is relevant to this either.)

 

Anyway I created 3 events just north of Punxsutawney, PA (Phil the Groundhog’s hometown!). Punxsutawney is located at the very bottom (South) in Jefferson County.

 

The three events are “Paving”, “Tree Trimming” and “Line Painting”.

 

 As you can see from the spreadsheet, typically an event is shown in PennDOT’s data as the State Route it is on (ST_RT_NO), then which Segment it begins in (SEG_BEG), then the exact “offset” place of beginning within that segment (OFF_BEG).  So, for example… if the (OFF_BEG) is “0”, then the Event is beginning right at the exact beginning of the segment.  If the (OFF_BEG) said “1,000” then the exact beginning of the Event is starting 1,000 feet from the beginning of the segment.

 

Then the segment where the Event is ending is stated as (SEG_END) and the exact location of its end is (OFF_END). This is the number of feet from the beginning of that segment.  So, again, if it said “0” that would mean the Event is ending right at the very beginning of that segment.  If it said “1,000” then it is ending exactly 1,000 feet from the beginning of that segment.

 

So, how would I link this simple Event table to my Map and show the exact places (as Lines, not points) where the three events are taking place? I’ve attached a simple illustration showing each Event and approximately where they would be happening on the map if you successfully did this.

 

I would like to take any spreadsheet with those Fields list above and quickly map Events (as Lines) in ArcMap. Is this possible?  Usually we would need to map hundreds of events, and even overlapping events, so doing this all by hand is out of the question.  Thank you for any help you can provide.

Raymond

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by Anonymous User
Not applicable

Thanks Raymond. I will take a look at this, this week.

Tom

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RaymondArotin1
New Contributor II

I just wanted to add some additional information.  I found a tutorial method that is used with GeoMedia.  ATTACHED PDF.  I'm just including this as an example of what I was expecting within ArcMap (the general method, the dialog boxes).  It seems to be a very simple straight forward method.  In particular, (page 3) shows the Measure field options that allow you to pick SEG_BEG, OFFSET_BEG, SEG_END, and OFFSET_END.

Again, thanks for any help you can provide.

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RaymondArotin1
New Contributor II

Has anyone figured anything out on this yet?  It will be tremendously beneficial to our Agency to be able to use our Segment-based method to quickly map features.  Otherwise, we have to go about this another way.  Thanks for any help.  I'm going to need to figure something out soon.

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by Anonymous User
Not applicable

Raymond,


Apologies for taking so long with this. I just got slammed with other work. But I think I have a good solution for you. First off, as you already know, the ArcGIS approach is different from the segment approach you have. Instead of locating using segments and offsets, we use a continuous route with cumulative measures. With the Roads and Highways extension we do support offsets natively. This is done by converting offsets locations to route and measure. The nice thing about this approach is you can offset from any point geography, like a sign or reference marker. Out of curiosity, are you segments referenced along the roadway with physical signs or markers? If so, those would be the offset features in Roads and Highways. If you don’t have that physical reference in the field, how do field people locate these LRS locations using segment and offset?

With all that said, we can locate your events using some simple geoprocessing. In the attached zip there is a toolbox called “Toolbox.tbx” that contains the following three models.

  1. Create PennDOT Routes. This model creates a continuous route system using CITY_CODE and ST_RT_NO. These are the LRS key fields that you setup in Geomedia. I saw in the PDF that you shared that you also use SIDE_IND as a LRS key field but I didn’t find that in the data that you provided. This could be easily included if you needed it. This model only needs to be run once to generate the PolylineM routes in ArcGIS. I already ran them on the data you provided and the result is “Routes “ in the PennDOT.gdb Geodatabase.
  2. Convert Excel Table. This is a built in function for converting an Excel worksheet to a table. I just included it in this toolbox for easy access. The Locate model needs to have a table input so you need to run this first to convert the worksheet to a table.
  3. Locate PennDOT Events. This model locates an event table using the following parameters: City Code, State Route Number, Segment Begin ID, Begin Offset, Segment End ID, and End Offset. The model takes that input and converts it to RouteID, FromMeasure, and ToMeasure and then locates it on the PolylineM Routes.

Locate PennDOT Events Geoprocessing tool

The nice things about this approach is once you have your ArcGIS routes created you can execute the “Locate PennDOT Events” tool as many times as you want. You could also publish it to ArcGIS Server and execute it from a Web AppBuilder web application. If your interested in this, just let me know. Actually I’d be happy to talk with you about this process. If you are interested just email me your contact information at tbrenneman@esri.com.

I hope you find this useful. Please let me know if you have any follow up questions.

Tom

by Anonymous User
Not applicable

And just the toolboxes in 10.5 and 10.3 format.

JohnFix1
New Contributor III

Raymond,

PennDOT has a web app called "GIS-IQ" that allows you to drag and drop an excel file with county/route/segment (begin/end)/offset (begin/end) and map those features in the app. It's very easy to use. This app was created in BPR's GID.

It is an Esri based app, supported with ArcGIS Enterprise.

I hope this helps.

John

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