[Talk-ca] canvec / shp-to-osm

Sam Vekemans acrosscanadatrails at gmail.com
Sun Oct 25 23:06:07 GMT 2009


On Sun, Oct 25, 2009 at 3:15 PM, Frank Steggink <steggink at steggink.org>wrote:

> Hi,
>
> I think to know what is going on. I've tried to convert the residential
> areas of 031I08 myself, and I got an OSM file with an outer polygon.
> However, the outer polygon has no tags. Also, it looks that Sam's batch
> files run shp-to-osm with the -t parameter, which suppresses the output of
> features without any tags.
>
> Solution:
> * shp-to-osm needs to be adjusted, so that the outer polygon will get the
> tags, but the inner polygons will not.
>

Im running the script how with that change.. to see how it works...


> * shp-to-osm should be called without the -t parameter.
> Is this possible?
>
> However, that means for tiles that have no residential areas a file with
the size of 0 bytes will be created.   (not a problem, as i could do that
for all the features... but you'd end up with 80 0meg files.   that would
cause a headache when someone looks at it for the 1st time)  ... or we could
just do that for residential areas.

What i DID do was create an 'extra' file, in the 'extra' folder, that
extended the max nodes to 2 million. (or i could just remove that toggle),
and a full .osm file will be created.
... but remember that the API can only handle 2000 nodes.

and what i also did was create a 3rd line on the bat file that  omits the
'-t' and also in the 'extra' folder, as that should do the trick.

Frank
>
> Frank Steggink wrote:
>
>> Hi Sam,
>>
>> I've just downloaded some CanVec data, and had a look at sheets 031I07 and
>> -08. I wonder what you mean by uploading all "sub-residential files". I
>> understand that the data is separated over multiple files, because of
>> certain limitations. In the residential OSM files I also see no polygons
>> with a multipolygon relationship of "outer". So,this means that the outlines
>> of places like Trois-Rivieres and others are missing. The same issue is
>> going on with wooded areas. The data is converted with Canvec2OSM version
>> 0.9.4.
>>
>> I had a closer look at the raster file (from Toporama) of sheet 031I08,
>> because there is much less data, and I looked at the village of Gentilly
>> (see [1]). This is in the center of the sheet. The raster file suggests that
>> a multipolygon relationship should be in place, but the vector file
>> (BS_1370009_2_Residential_area0.osm) shows only the two inner polygons. Are
>> the outer polygons stored in a different file, or are they not converted at
>> all? The shape of the outer polygon doesn't look to be complex, so I don't
>> think the max_nodes threshold would be exceeded. Looking at the OSM file:
>> there is only one multipolygon relationship in it, but it only refers to the
>> two inner polygons, and not to any outer polygon at all.
>>
>> One note regarding multipolygons: the inner polygons shouldn't have any
>> tags at all. See [2].
>>
>
Ya, i noticed that with the water features i was playing with the other day.
So that needs to have a closer look into.

>
>> Anyways, some clarifications about what is going on, and how the data
>> should be interpreted would be welcome.
>>
>
Thats where the readme.txt file comes in to play.  As it gives some
instructions.  But it might need a little fixing up.


>  I'm reluctant to import data which looks not correct. For the rest, keep
>> up your good work :)
>>
>
Thanks :)

>
>> Regards,
>>
>> Frank
>>
>> [1] http://osm.org/go/cKHX9ApT-
>> [2] http://wiki.openstreetmap.org/wiki/Multipolygon
>>
>> Sam Vekemans wrote:
>>
>>
>>> Hi Richard,
>>> i think your refering to the large multi-polygons such as
>>> 'residential_area', and it 'appears' to be inverted.
>>>
>>> Here's the majic; when all the sub- residential.osm files are uploaded
>>> to OSM, it renders correctly.
>>> In JOSM, you need to zoom out and load the area, to see it.
>>>
>>> I think i'll load a region of NFLD in the next cuple days to test my
>>> hypothises.
>>>
>>> Sam
>>>
>>> ps. I cc'd talk-ca as this was mentioned b4.
>>>
>>> On 9/22/09, Richard Weait <richard at weait.com> wrote:
>>>
>>>
>>>> Dear gentlemen,
>>>>
>>>> I've had a look at some of Sam's test areas.  In 1435 files there are
>>>> zero occurrences of Relation=outer.
>>>>
>>>> So at some point we started calling relation=outer, relation=inner or
>>>> completely dropping outer relations by mistake.
>>>>
>>>> I do still see rare nested ways, but both are marked as inner, and are
>>>> on separate layers after --maxnodes
>>>>
>>>> I've run 0.6.1 again with an old rules file and see the same problem
>>>> so I believe that this is an issue in shp-to-osm.
>>>>
>>>> Ian can you check a 0.5.0 - generated file and see if it contains any
>>>> "outer"?
>>>>
>>>> Best regards,
>>>> Richard
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
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>>
>
>
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