What is the relation between cropping a .osm file by osmium cat and the crop! function provided in OpenStreetMapX package?

General Usage
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I’m confused by the two cropping operations as mentioned in the title. My goal is to obtain the roadnetwork of a certain area using open street map data.
Reference link: What's the general algorithm to draw a road network of a certain area? - #34 by ImreSamu
I download the .osm.pbf file, say a.osm.pbf from GEOFABRIK // Downloads, and then using command osmium extract --bbox 10,10,40,40 a.osm.pbf -o b.osm.pbf to extract or crop the file based on the bbox given by the four parameters. Then, I used osmium cat b.osm.pbf -o c.osm to transfer the .osm.pbf file into a different format .osm. I also have the a.osm file obtained from command osmium cat a.osm.pbf -o a.osm. The file a.osm has size roughly 600MB, while the c.osm has size roughly 100MB.

When I use c.osm with my code, during the function call get_map_data, I realized that there is the other function OpenStreetMapX.crop!(osmdata, crop_relations = false). I understand that the purpose of this function is to crop the nodes, ways, relations based on a given bounds. But I have already crop / extract based on a known bbox already using osmium commands. So I do not need this operation. Am I missing something or ? The other small/side question is, what is the relation between nodes and vertices? From my understanding, nodes are more concrete, and vertices are more abstract I guess. Nodes refer to the nodes elements in .osm file. Do I understand it correctly? Any comments are greatly appreciated indeed!

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@ pszufe, @ Bartosz_Pankratz

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partial answer …

As I know - Geofabrik extract the (country/region) data

imho : the osmium extract should be enough with the default complete_ways strategy.

for extreme cases - for example - you want full ‘EuroVelo’ data ( == European cycle route network ) - you need different extraction strategy … and you have to know deeply the osm relation types …

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Thank you for your quick reply. What I need is car route network, something similar to cycle route network. Could you provide more references?

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  • can you clarify what you mean by “car route network”?
  • what is your real problem? what you want to solve?
  • what is you background?

For example …
the OSRM is using this tags for car routing ( building - car route network )

Telenav : OSM Tags for Routing:

Valhalla : routing tags:

General OSM Wiki info about routing:

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By “car route network”, I mean “driving road/route network”. I need to simulate / visualize cars driving on a road network, from given location A to location B.

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not too much info … :slight_smile:
but probably in your case the

  • osmium extract --bbox 10,10,40,40 a.osm.pbf -o b.osm.pbf

is enough for you. ( but you have to make some experiments for testing this … )

on the other hand …

IF you need speed limits … THEN you need administration areas to decode some values

IF you need road hierarchy ; THEN you need osm relations …

etc …

so this is a complex problem … good luck ! :slight_smile:

disclaimer: I have not used the OpenStreetMapX package yet … because I am mostly loading the OSM data to the Postgres/Postgis database … so probably my comments not the global optimum … sorry ;

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