ankurt

Line features : Merging, dissolving, spatial join or what?

Discussion created by ankurt on Apr 16, 2012
Latest reply on Apr 16, 2012 by ankurt
Hi,

I have a set of shapefiles containing line features representing a road network. Each shapefile has a different set of line features corresponding to different attibutes of the roads. One set of features can contain speed limits for different segments and another set of features can contain the road width. Obviously, such things as the speed limits and the width of the road can change at different locations which means that sometimes features from different shapefiles don't share start- and/or end vertices, but sometimes they do. However, they are all "perfectly" aligned on top of a background shapefile, containing the "basic layout" that can be compared to a dissolved set of features. Each line feature in this background shapefile has a unique id and any line feature from any other shapefile will fit completely within a line feature in this background, and the background id:s will match. In some cases, several smaller line features in a certain shapefile will fit within one background feature and in that case they will all have the same unique id. In short, the line features from the different shapefiles are like different layers representing different attributes and they overlap "perfectly". However they may have different start and ending vertices. But no line feature will stretch across a start- or ending vertex of the background line features in such a way that there is a one-to-many relationship between these that can be identified using the "background id".

The question now is how to join these layers so that each combination of attributes from the different shapefiles is represented by a single line feature shapefile. Since they often (but not always) have different start- or ending vertices, I assume that one needs to start with generating a new set of line-segments with a start-ending vertex as soon as any of the other features has a start-ending vertex and for each of the new line features, aggregate the relevant attribute values into the correct attribute combination.

I still haven't figured out a way of doing it...

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