Hot answers tagged geometric-network
4
Try finding all polylines where IGeometryCollection.GeometryCount > 1.
I think the example for calculating vertex count could be adapted to do this with the field calculator.
3
Short answer to the question "Can we create relationship classes based on a geometric network?"
Relationships yes, relationship classes no.
Long answer:
A relationship class as defined by ESRI deals with how attributes inside fields relate to each other in two or more tables. A relationship class can be one to one, one to many or many to many. It can be ...
3
After making a lot of testing, I found that the most accurate way to detect geometric network actions(such as connect, disconnect) in an IObjectClassEvents::OnChange event is to use the interfaces IRowChanges and IFeatureChanges to determine if something changed.
Private Function NetworkConnectivityChanged(ByVal obj As ESRI.ArcGIS.Geodatabase.IObject) ...
2
First, let me say that I share your frustration with the inability to set flow direction where there is a split with multiple sinks. As far as I can see, you have set up your dataset, layers and network properly.
The explanation that I received is that when there are 2 or more sinks on a common junction, each sink potentially has the ability to draw flow ...
2
If the end points are not marked as such, you will have to find a definition that can unambiguously identify an end point. Depending on your geometry, that may be next to impossible, because an algorithm cannot tell whether the points
y
| A B C D
+----------x
represent a simple line
A-B-C-D
or a polyline
A-B C-D
unless you have a clear criterion ...
2
There are errors that one can get due to several wrong bits. Please refer to the help page Identifying geometric network build errors. Most often these errors have to do something with errors in features' geometry.
I would start with:
1) Click Customize > Toolbars > Geometric Network Editing.
The Geometric Network Editing toolbar is added to ArcMap.
2) ...
2
I'm sure you're aware of the nature of Open Street Map - it's a user collected and edited resource. If you're going to use this kind of information it would be largely down to you to fix these - and in the spirit of things update the information!
If you want a relatively clean network for analysis straight away, I'd suggest TIGER.
... but I think you'd ...
1
This is one of the many reasons why I keep a copy of 9.3.1 on at least one PC. If it ain't broke . . .
The functionality has indeed disappeared from inside the geometric network wizard. ESRI now recommends that you fix all snapping issues before building the geometric network. It's quite a bit more complicated but it can be done.
If your data requires a ...
1
The areas you are looking to create are called "subwatersheds" or subsheds. You can use the "Batch Subwatershed Delineation" tool in ArcHydro under the "Watershed Processing" menu. This will calculate subsheds from a set of points you define. The other input is a flow direction grid. This is a raster where the value of each pixel represents the direction ...
1
I heard back from an Esri rep that this is not currently supported, but hinted that it might be in the future.
I guess this means that until then, if I want to put a geometric network into the cloud, I'll need to use Amazon EC2. Another Esri rep I spoke with at the Dev Summit said there won't be any OOTB tracing in 10.1, and recommended that I write an ...
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