[R-sig-Geo] Overlaying SpatialLines by SpatialPolygons

[Mathieu Rajerison]

Hi,


Thanks a lot for taking my problem into account.

I've put a data subset as attached file. It contains two files: roads.shp
and cities.shp.

routes is the result of an intersection between initial complete roads file
and cities. Features in actual roads have been split up, therefore gContains
test can directly be executed.

In roads, a column named "contained" indicates whether the road is
considered contained or not after my gContains test


Mathieu

2011/6/8 Roger Bivand <Roger.Bivand at nhh.no>

> On Wed, 8 Jun 2011, Mathieu Rajerison wrote:
>
>  Hi,
>>
>>
>> First, thanks to all. It's the first time I use rgeos.
>>
>> I finally managed to get a layer of roads (routes.bdc object) that are the
>> result of the intersection between roads and cities (bdc object).
>>
>> But the problem now is that some intersected roads are not considered
>> being
>> contained in any of the cities, although they should be, as the result of
>> an
>> intersection. I put two images of them as attached files (city contours in
>> light orange, roads in blue, and some selected roads in yellow)
>>
>> http://hpics.li/750b6bf
>> http://hpics.li/578ab3d
>>
>
> What is needed is a reproducible example, so that the classes of the output
> objects become evident. Can you provide such an example with publically
> available data, or put a relevant data subset on a link?
>
> Roger
>
>
>
>> Here is the code, for the moment:
>> ####
>> library(rgeos)
>>
>> pls <- slot(bdc, "polygons")
>> pls1 <- lapply(pls, checkPolygonsHoles)
>> slot(bdc, "polygons") <- pls1
>>
>> routes.bdc = gIntersection(routes, bdc)
>>
>> routes.bdc = slot(routes.bdc, "lineobj")
>>
>> bdc.contains = gContains(bdc, routes.bdc, byid=TRUE)
>>
>> nbdc = apply(bdc.contains, 1, function(x) as.numeric(which(x)))
>>
>> apply(bdc.contains, 1, function(x) any(x))
>> ###
>>
>> apply(bdc.contains, 1, function(x) any(x))
>> mentions many FALSE values which indicate that some roads are not
>> contained
>> in any city...(?)
>>
>>
>> Any help would be greatly appreciated!
>>
>> Thanks again
>>
>> 2011/6/7 Roger Bivand <Roger.Bivand at nhh.no>
>>
>>  On Tue, 7 Jun 2011, Mathieu Rajerison wrote:
>>>
>>>  Thanks for the answer!
>>>
>>>>
>>>> I think I surely have to use gIntersection then gLength for this purpose
>>>>
>>>> I've tried gIntersection like this:
>>>> routes2 = gIntersection(routes, bdc)
>>>>
>>>> But I get the following message:
>>>> Erreur dans createPolygonsComment(p) :
>>>>  rgeos_PolyCreateComment: orphaned hole, cannot find containing polygon
>>>> for
>>>> hole at index 1
>>>>
>>>> Do you have an idea why I get this message and how to correct it?
>>>>
>>>>
>>> The polygon object is malformed, and at least one polygon claims only to
>>> be
>>> an interior ring, which is impossible. You need to look at how you are
>>> creating your SpatialPolygons object, and possibly use
>>> checkPolygonsHoles()
>>> in maptools to repair damaged objects. Typically running:
>>>
>>> library(maptools)
>>> pls <- slot(bdc, "polygons")
>>> pls1 <- lapply(pls, checkPolygonsHoles)
>>> slot(bdc, "polygons") <- pls1
>>>
>>> may help. As Colin says, posting a link to the polygons object, and to
>>> code
>>> used to create it, may be helpful.
>>>
>>> Roger
>>>
>>>
>>>
>>>>
>>>> 2011/6/7 Roman Lu??trik <roman.lustrik at gmail.com>
>>>>
>>>>  Package rgeos has all sorts of functions that might come handy.
>>>>
>>>>>
>>>>> Cheers,
>>>>> Roman
>>>>>
>>>>>
>>>>>
>>>>> On Tue, Jun 7, 2011 at 6:13 PM, Mathieu Rajerison <
>>>>> mathieu.rajerison at gmail.com> wrote:
>>>>>
>>>>>  Hi,
>>>>>
>>>>>>
>>>>>>
>>>>>> I have a SpatialLines object representing roads and a SpatialPolygons
>>>>>> object
>>>>>> containing cities.
>>>>>>
>>>>>> I'd like to know how to overlay a SpatialLines object by
>>>>>> aSpatialPolygons
>>>>>> object.
>>>>>>
>>>>>> I'd like to know the total distance of roads that cover each of my
>>>>>> cities.
>>>>>>
>>>>>> Is it possible?
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Mathieu
>>>>>>
>>>>>>      [[alternative HTML version deleted]]
>>>>>>
>>>>>> _______________________________________________
>>>>>> R-sig-Geo mailing list
>>>>>> R-sig-Geo at r-project.org
>>>>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> In God we trust, all others bring data.
>>>>>
>>>>>
>>>>>        [[alternative HTML version deleted]]
>>>>
>>>>
>>>>
>>>>  --
>>> Roger Bivand
>>> Economic Geography Section, Department of Economics, Norwegian School of
>>> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
>>> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
>>> e-mail: Roger.Bivand at nhh.no
>>>
>>>
>>>
>>        [[alternative HTML version deleted]]
>>
>> _______________________________________________
>> R-sig-Geo mailing list
>> R-sig-Geo at r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>>
> --
> Roger Bivand
> Economic Geography Section, Department of Economics, Norwegian School of
> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand at nhh.no
>
>
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