Q: Line matching

I have two line themes, that each represent the same road network. They
have been digitised from different sources, and with different precession
and skill. One has been segmented, something like line topology, where all
lines are split at all nodes.
I need to join the two themes in order to copy an attribute from one to
the other.
There are no attributes that can act as key, and a spatial join will never
be perfect, due to the differences in digitisation.
Are there any tools in, e.g. network analyst to handle such cases?
Do you know of any user developed scripts extensions or the likes which
apply to this type of problem?

All comments are appreciated...

Best Regards
Martin Hvidberg

The process of spatially matching up lines to transfer attributes from one
dataset to another
is called "conflation". This is (or at least used to be) possible with
ArcInfo. In ArcView 9, you
can do some of that using the Spatial Adjustment toolbar. Depending on how
well the two
datasets match up, this may be easy or require quite a bit of work.

I hope that helps.

Robert van Waasbergen

Hi Robert

Are you saying this is available in good-old ArcInfo, like in ArcInfo
command line versions?
If so, please, are there any need of aexentions of any kind?

Will look up "conflation" in ArcInfo help when I get to the right
computer...

:-) Martin


On Thu, 30 Jun 2005 16:15:41 -0500, Robert van Waasbergen




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wrote:


When I get into it it seems that Matchcover is the thing I need.
Only it performs sub-optimal. If a peice of road is in one cover digitized
as a continous arc from roadcross to roadcross, and in the other cover is
digitized as to or more arcs over the same distance, ei. having pseudonode
allong the way, then they are not matched by Matchcover.

Maybee I can Clean these pseudonodes away?

:-) Martin

Given ArcInfo (command prompt), i would try the following:

1. Run the BUFFER command on the input line coverage, finding the best
buffer size on trial and error.

2. IDENTITY or INTERSECT the buffer polygons with the output line coverage
(line in polygon overlay)

3. From the result, which will include some "spaghetti" as a result of
overlapping buffers / not found sections, try to work out a way to aggrate
the results.

4. Think again, there's no trivial way of automatically matching two
networks, try again starting from step 1. at least once....

Good luck,

Bart