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OSM data is split into segments ("ways", in OSM parlance) whenever any property changes (name, surface, width, legality of herding yaks, ...). You have to decide what you mean by "the same road", assemble the bits that join up geometrically, and cut up the result according to your definition of "the same road". This might be ...


2

Changing layer's CRS is wrong approach in this case. You do that only if you believe QGIS did not recognise CRS correctly, or layer has by mistake wrong CRS assigned to it. What you need to do is reproject the layer, meaning create new converted one in the desired target CRS. Simply right click on layer, choose Save as, and choose your target CRS. Saying so, ...


2

Try to insert this $x and $y expression in "Default value" field and check "Apply default value on update" box.


1

You need to consider several things before making a spatial data file or database table. Several applications and APIs will create the data on disk for you. QGIS is easy with menu Layer > Create Layer > ... You at least need to know: You data projection. Latitude - longitude (EPSG: 4326 - WGS 84) seems right for you with your data extent The columns (...


1

One of the joys of open source software is the easy you can "borrow" code from another project. GeoServer is built using GeoTools and can produce a legend graphic from a list of layers and styles. Much of the work for that can be found in BufferedImageLegendGraphicBuilder. Once you have one or more legend images it's a simple case of learning how ...


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