Referenciación lineal y cálculo de nuevos valores de polilínea

Question

<\/HEAD> <\/DIV> <\/DIV>Por favor, vea el archivo adjunto. Pude agregar segmentos de Polyline y luego dividir la polyline en secciones Urbanas y Rurales, pero cuando dividí las líneas entre áreas rurales y urbanas, los campos que aparecieron fueron para la capa de límites de Cities o ? y no para la capa de Polyline (postmiles).<\/DIV> <\/DIV>Lo que necesito hacer es recalcular (¿Calibrar?) las rutas basándome en las medidas Postmile en los nuevos segmentos Urbanos y Rurales para que las medidas de Inicio\/Fin sean desde el PUNTO DE INTERSECCIÓN DE LÍMITES hasta el PUNTO DE INTERSECCIÓN DE LÍMITES.<\/DIV> <\/DIV>Localizar características a lo largo de las rutas es manual y no eficiente para lo que necesito ayuda.<\/DIV> <\/DIV>Si puedo agregar segmentos y luego dividirlos en segmentos Urbanos y Rurales, estoy a 2\/3 del camino.<\/DIV> <\/DIV>¿Qué funcionalidad en Linear Referencing puedo usar?<\/DIV> <\/DIV>Gracias,<\/DIV> <\/DIV> <\/SPAN><\/P>Daniel T. Brenner<\/SPAN><\/P>RESEARCH ANALYST I (GEOGRAPHIC INFORMATION SYSTEMS)<\/SPAN><\/P>DIVISION OF RESEARCH, INNOVATION, and SYSTEM INFORMATION <\/SPAN><\/P>Highway System Information and Performance<\/SPAN><\/P>1120 N Street MS 38<\/SPAN><\/P>Sacramento, CA 95814<\/SPAN><\/P>(916) 657-4277<\/SPAN><\/A><\/P>(510) 593-7547<\/SPAN><\/A> celular<\/SPAN><\/P>daniel.brenner@dot.ca.gov<\/SPAN><\/A><\/P> <\/SPAN><\/P>Considera lo no considerado. <\/SPAN><\/P>La certeza no es algo seguro!<\/SPAN><\/P><\/DIV><\/DIV><\/BODY><\/HTML>

RichardFairhurst · Answer

Create Routes does not create fields with measures in them, nor does any other tool.  Create Routes creates coordinates with measures stored in the geometry of the line, just like the X and Y coordinates at every point that makes up the line.

It is your job to create the From_M and To_M fields and calculate the M coordinates into them.  You would do the same thing if you wanted to have fields display the X and Y coordinates for the start and end point of the line (although, unlike the M coordinates, for X and Y coordinates there may be other tools that also can accomplish this task).  The fields you would create to store all of the coordinate types would all be double fields.  Below are sample coordinate fields for all the possible coordinate values of the points at the start and end of your polylines that you could create and the Python calculations you would need to run to populate them.

Polyline From coordinate calculations:

FROM_X field is calculated using a Python calculation of !Shape.FirstPoint.X!

FROM_Y field is calculated using a Python calculation of !Shape.FirstPoint.Y!

FROM_Z field is calculated using a Python calculation of !Shape.FirstPoint.Z!

FROM_M field is calculated using a Python calculation of !Shape.FirstPoint.M!

Polyline To coordinate calculations:

TO_X field is calculated using a Python calculation of !Shape.LastPoint.X!

TO_Y field is calculated using a Python calculation of !Shape.LastPoint.Y!

TO_Z field is calculated using a Python calculation of !Shape.LastPoint.Z!

TO_M field is calculated using a Python calculation of !Shape.LastPoint.M!

DanielBrenner · Answer

Richard,

Thanks for all of this.  I will work with it when I am in the office on

Thursdsy, but I will say that I did use the Make Routes tool in LR but I

didn't get any Measure values for some reason (just ID fields)???

If there is a better term other than Aggregation for adding  measure values

for a poly line with multiple segments together into one measure, please

enlighten me??

Will resoon better on Thursday.

Thank you for your time and effort.

Daniel Brenner

RichardFairhurst · Answer

Have you ever used the Create Routes tool to aggregate your segments?  This tool not only joins segments together, it adds measure (M) coordinate values (M is store the same way that X, Y or Z coordinates are stored) to create M-Aware polylines based on several methods (frequently using line length).  If you don't have a set of M-Aware Route polylines you cannot use Linear Referencing tools like Locate Features along Routes.

It is unclear what you mean by Aggregating lines.  Aggregating lines using tools like Dissolve that do not add M coordinates to polylines is not linear referencing.  Nor is just by assigning many lines a common value, but leaving them as separate lines.

Each coordinate of the polyline is assigned a measure or M value.  In the simplest case, if you had a two point line with a starting coordinate with a measure of 0 and and ending coordinate with a measure of 8, if you split that line, the coordinate created at the split will interpolate the distance of that point between 0 and 8.  So if the split was at measure position 6, the line with a starting measure of 0 would now end at 6, and the line with an ending measure of 8 would now start at 6.

I gave you the Python calculation to get these coordinates into a From and To field already, if your lines are M-Aware Routes.  Read more on Linear Referencing if you still do not understand what an M-Aware Route is, since they are the foundation of LR.