I have been tinkering with a network I created and generating service areas. Comparing it to ESRI generated service areas (using ArcGIS Online) for the same point shows a drastically different service area.
So I started looking up network dataset tutorials. Most of these show you how to create a network, but not what a fully functional and accurate one actually has in terms of data (roads, rails, bus stops, stop signs, traffic signals....etc).
So my main question is, what data should I have in my dataset and what would the network settings look like?
My secondary question, is what features and settings does the ESRI network contain?
Just my $00.02....
The ideal network may or may not contain everything you mention above. The first question one needs to ask is
What is my objective when developing my [insert here]?
This goes for just about anything right? Databases, Networks, etc.
I used NA for a number of years for 9-1-1 dispatch. All I needed was a centerline network with speed limits and the locations of fire stations. I used universal turn impedances for right, left, and straight (no turns) through any given intersection. Using speed limits along with centerline segment length, I was able to calculate the amount of time it took to traverse a segment. Some those up and you get a relative drive time to a given incident. The objective was met: I would dispatch based on drive time: Minimum drive time response gets dispatched.
As the complexity of any GIS analysis increases, as does the need for more complex (read; precise and accurate) data. If all you want to do is draw a map of the counties in your state, you just need a polygon feature class of the counties with their names. But what if you want display population distribution, your data needs just changed. Now you want to display the population of a given demographic? You get the picture....
It may be that the settings you have chosen are different than what ESRI has for their network dataset. I have not used ESRI's service, but I wonder if the settings are exposed? That way you could compare them to yours. It could be as simple as different choices for Impedance or Turn Restrictions.
Another potential factor is the data itself. It may be that the data is different. For example, you may have more modern information, where the ESRI data may be missing streets.
Chris Donohue, GISP
As an example of how data may be different, check out the news story I posted in this thread about a roads issue that came up in the City I work at. One of the realities of this business....
EDIT: Scratch that, even though it is listed with a lead in, the story no longer seems viewable (but the ads still work). So no video to watch from the news network.
Chris Donohue, GISP
You can get information on the routing data that is used for the ArcGIS Online services here:
Also note that most commercial data do not include information on which intersections have traffic lights or stop signs.