[gdal-dev] converting lines to linestrings

[Joaquim Luis]

On 27-08-2011 17:27, Frank Warmerdam wrote:
> On 11-08-27 02:10 AM, Zoltan Szecsei wrote:
>> Hi,
>> I'm not sure if this is the correct list to address this on, but ....
>>
>> I have lots of files, each with a bunch of lines that start & stop on 
>> each
>> others ends and I need to convert them into line strings, file by file.
>>
>> Is there a command-line (batch) way I can do this?
>>
>> They are currently in DGN (v8) format but I can convert them to SHP, 
>> MID/MIF or
>> whatever.
>>
>> What I'm looking to do is to create a batch pipeline that, file by 
>> file, will
>> take each line, and if either of its ends are within 0.5m of another 
>> line-end,
>> then join them together to form one line string, then output that 
>> "snapped up"
>> data to disk. (any format)
>
> Zoltan,
>
> I do not believe you can accomplish this with ogr2ogr.  But it is 
> certainly
> possible to write a script, for instance in python, that would accomplish
> this in combination with the OGR API.  That is the approach I would take.
>

Hi,

The GMT program 'gmtstitch' will do just that but you will have to 
convert the DGN files to gmt with ogr2ogr

Joaquim