[gdal-dev] Create a network

[Dmitry Baryshnikov]

Hi,

In case of polylines (i.e. road segments, single layer) - each polyline 
is vertex and edge is pure virtual (so it identifier is -1).

There are different cases, for example:

1. Water network with pipes (vertices) and edges (valves)

2. Road network - each road segment is vertex, edges are virtual

3. Product supply chain - warehouses, shops are vertices, edges may be 
virtual or real roads.

Best regards,
     Dmitry

19.08.2020 14:38, marto salata пишет:
> Thank you very much for your fast reply.
> regarding step 2, i have a polyline shapefile, how to get the vertices 
> required in step 3 so i can connect them.
> i know the gfid in the imported shapefile, but from where i can get 
> the vertices?
>
> On Wed, Aug 19, 2020 at 11:25 AM Dmitry Baryshnikov 
> <bishop.dev at gmail.com <mailto:bishop.dev at gmail.com>> wrote:
>
>     Hi,
>
>     You need to follow these steps:
>
>     1. Create empty network
>
>     > gnmmanage.exe create -f GNMFile -t_srs "EPSG:4326" -dsco
>     "net_name=my_network_1" C:\tmp\gnmnetwork
>
>     2. Load your data
>
>     > gnmmanage.exe import lines.shp -l lines C:\tmp\gnmnetwork
>
>     Repeat for all your layers
>
>     3. Connect features to create network. Features identifiers set
>     while importing your spatial data. Use ogrinfo to check them.
>
>     > gnmmanage.exe connect 1 2 -1 C:\tmp\gnmnetwork
>
>     4. Perform shortest path using Dijkstra
>
>     > gnmanalyse.exe dijkstra 1 2 -ds shortestpath.shp -f "ESRI
>     Shapefile" -l shortestpath C:\tmp\gnmnetwork
>
>
>     Some links:
>
>     * https://trac.osgeo.org/gdal/wiki/geography_network_support
>
>     * https://nextgis.com/blog/gnm/ <https://nextgis.com/blog/gnm/>
>
>     * http://gsoc2014gnm.blogspot.com/
>
>     Best regards,
>          Dmitry
>
>     19.08.2020 07:31, marto salata пишет:
>>     dear GDAL team,
>>     how  i can create a network using gnmmanage.exe from a polyline
>>     shapefile, so i can perform a dijkstra with gnmanalyse.exe
>>
>>     best regards
>>
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