I download shapefile of Alberta from GEOFABRIK in order to work with the roads shapefile. The problem was that I get an attribute table with 94,644 rows that was slowing down the computer, additionally to the fact that I get every small road and just the main one as I wanted.

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I looked in the attribute table and found that the road type are classified in the fclass column. As described here I use the categorized function to classify the different road types, so I was able to display only the primary roads. enter image description here

Also, it is possible to change the line style, by clicking the "Symbel" bar. enter image description here

However, it was only a partial solution, I still have a lot of unnecessary data seem to slowing down me computer. I was looking for a way to extract the data in need, and to work with this kind of big database.

1 Answer 1


In order of extricating data I used the "Split vector layer" function.

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I choose the layer I was working on and in the "unique ID field" I choose the fdass column that have the different roads type classification. enter image description here

It took some time, but at the end I head diffrent shapefiles for each road type. Know I was able to work only with the road type I needed, and if needed to upload more road layers. It was much easier in compared of working with one big attribute table.

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