how to calculate the "FT Minutes" "TO Minutes" fields

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03-01-2016 08:54 AM
GustavoCordero
New Contributor III

I am using arcgis 10.3

I am creating information network dataset with historical traffic data

I need to fill "FT Minutes" "TO Minutes" fields

but not how to calculate this data in my street feature class

could help me and tell me how to calculate this and fill this information

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ChrisDonohue__GISP
MVP Frequent Contributor

In the City I am with, the SPEED_FT and SPEED_TF are populated with the speed in Miles per Hour that one can transit the segment.  So for general routing purposes, we typically use the posted speed limit set for the street segment for travel in that direction (To-From or From-To).  For example, residential areas are typically 25 MPH (and that is what a driver would see signage for).

So you want to consider what you are modelling to then be able to come up with a reasonable speed for the segments.  For example, if your goal is to create a network dataset to model response times for emergency vehicles, you probably would want to seed in the speed an emergency would transit the segment in that direction (TF, FT).  In contrast, if the goal is to create a network dataset of walkability, the speed would probably be based on how fast an average person could walk the segment in that direction.  It all depends upon what your goal is.

Note that determining the values for each segment may require quite a bit of coordination with the interested parties and research by subject matter experts.

Chris Donohue, GISP

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ChrisDonohue__GISP
MVP Frequent Contributor

Here's an example to calculate the From-To (FT) Minutes using VBScript in Field Calculator running against a streetline feature class in an Enterprise Geodatabase/SDE (note this formula can vary depending upon how you set up your data):

[Shape.len] / [SPEED_FT] *(60/5280)

For the To-From segments, it looks like this:

[Shape.len] / [SPEED_TF] *(60/5280)

Assumptions:  calculation assumes values pulled from SPEED_FT and SPEED_TF are the speed in Miles per Hour when traversing the segment.

Chris Donohue, GISP

GustavoCordero
New Contributor III

Thank you very much for answering

I have one last question if it is not too much trouble

my question is how to calculate [SPEED_FT] and [SPEED_TF]

Thank

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ChrisDonohue__GISP
MVP Frequent Contributor

In the City I am with, the SPEED_FT and SPEED_TF are populated with the speed in Miles per Hour that one can transit the segment.  So for general routing purposes, we typically use the posted speed limit set for the street segment for travel in that direction (To-From or From-To).  For example, residential areas are typically 25 MPH (and that is what a driver would see signage for).

So you want to consider what you are modelling to then be able to come up with a reasonable speed for the segments.  For example, if your goal is to create a network dataset to model response times for emergency vehicles, you probably would want to seed in the speed an emergency would transit the segment in that direction (TF, FT).  In contrast, if the goal is to create a network dataset of walkability, the speed would probably be based on how fast an average person could walk the segment in that direction.  It all depends upon what your goal is.

Note that determining the values for each segment may require quite a bit of coordination with the interested parties and research by subject matter experts.

Chris Donohue, GISP

GustavoCordero
New Contributor III

one more question. it is possible that a record of SPEED_FT or SPEED_TF

remain as "Null" and if this esposible exchange formula

[Shape.len] / [SPEED_FT] *(60/5280)

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