fields-attributesmergeqgisquerysql
I have a shapefile with a few thousand lines, each is a street segment. I'd like to merge all features with the same 'streetName' attribute into a single attribute. I only really care about the name of the street and it's geometry.
What would be the query necessary to do such a thing?
I'm new to GIS in general and have run into a problem I can't figure out how to fix. Excuse my noobness.
Thanks in advance.
Someone answered my question in a way that could help you using html annotations. QGIS html annotation relative paths under layer properties, display, you can insert the html to be displayed when hovering over features.
A simple solution for your question is using QGIS tool Distance to Nearest Hub. However, this tool does not bring into account your particular way of calculating distance using a 90 degree angle, as you specified. It simply measures the distance from each input point to the middle of each line feature.
Here is an example of how the tool can be used in a similar context:
Input:
Parameters (Hub Layer name attribute is the attribute from the line layer you wish to keep, in your case 'id'):
Output (same points as input, with added attribute):
As with any other processing algorithms, make sure both your layers are using the same coordinate systems (in your case you had a different CRS for each input layer). If the distance field (Hub Dist) is of importance to you too (not just which feature is closest), then make sure you are also using projected coordinate systems (not 4326).
Hope this helps!
Best Answer
Vector->Geoprocessing Tools->Dissolve does work for lines and will return a multi-geometry where the lines do not have coincident vertices.
Yet another option is available from PostGIS or SpatiaLite using the ST_LineMerge function.