[R-sig-Geo] [FORGED] Create a Spatial Weight Matrix based on road distance

[Rolando Valdez]

Dear Andres,

I could follow an example provided with the package, it was a little bit
simple, however, I got this message:

> dists <- osrmTable(loc = muns13, measure = "duration")
The OSRM server returned an error:
Error: The public OSRM API does not allow results with a number of
durations
higher than 10000. Ask for fewer durations or use your own server and set
its
--max-table-size option.

My sample size is 2,457

El vie., 21 de jun. de 2019 a la(s) 02:53, Andres Diaz Loaiza (
madiazl using gmail.com) escribió:

> Dear Rolando,
>
> The advantage of using Open Street Maps engine is that you can give the
> travel option. This means you can select whether are you traveling by bike,
> car or walking. The previous approach didn't consider this topic. For this,
> you should have added a vector layer depending on your position of the
> street you can take (or not). Open Street Maps project allow you two
> options: a service in which you give your current position, the position
> you want to reach and your transport method (giving you back the fastest
> route). Or the option to download the engine/algorithm compile by yourself
> (if I am not wrong is made in C or python) and then you can make your own
> calculation at your own computer. For the first option, the package OSRM is
> an interface in which send a request to the OSM web page and wait for an
> answer. With this method, you can send a couple of request at the same time
> but no to many (you should read the manual for this). Of course, also will
> depend on whether the OSM server is down or not (or busy).
>
> I have to say that I used some years ago this app and nowadays I know that
> for some cities OSM has more streets reported than the same google maps.
> Also is an open project and they let you download their data for free,
> contrary to what google maps do.
>
> All the best,
>
>
> Andres
>
> El vie., 21 jun. 2019 a las 4:30, Adrian Baddeley (<
> adrian.baddeley using curtin.edu.au>) escribió:
>
>> Rather than converting an object of class 'SpatialLines' or
>> 'SpatialLinesDataFrame' to the spatstat class 'psp' and then converting it
>> to the spatstat class 'linnet', it is safer and more efficient to convert
>> the SpatialLines* object directly to class linnet using
>> as.linnet.SpatialLinesDataFrame() from the package 'maptools'.
>>
>>
>> Prof Adrian Baddeley DSc FAA
>>
>> John Curtin Distinguished Professor
>>
>> Department of Mathematics and Statistics
>>
>> Curtin University, Perth, Western Australia
>>
>>
>> ________________________________
>> From: Rolf Turner <r.turner using auckland.ac.nz>
>> Sent: Friday, 21 June 2019 10:08 AM
>> To: Rolando Valdez
>> Cc: r-sig-geo using r-project.org; Adrian Baddeley; Ege Rubak
>> Subject: Re: [FORGED] [R-sig-Geo] Create a Spatial Weight Matrix based on
>> road distance
>>
>>
>> On 21/06/19 12:26 PM, Rolando Valdez wrote:
>>
>> > Dear community,
>> >
>> > Is there any way to create a spatial weight matrix based on road
>> distance?
>> > I am trying to use the road distance between two points instead of
>> > euclidean distance.
>> >
>> > I've seen that there is a package named osrm. Can anyone give some
>> advice?
>>
>> I don't know anything about "osrm".  Calculating "road distances" can be
>> done in the spatstat package reasonably easily, if you take the trouble
>> to represent your collection of roads as a "linnet" object.
>>
>> Given that you have done so, suppose that your linnet object is "L" and
>> that you have vectors "x" and "y" specifying the points on L (i.e. on
>> your roads) between which you want to know the distances.
>>
>> Do:
>>
>>      X    <- lpp(data.frame(x=x,y=y),L)
>>      dMat <- pairdist(X)
>>
>> The object "dMat" is a (symmetric) square matrix; dMat[i,j] is the
>> distance between point i and point j.  (Of course the diagonal entries
>> are all 0.)
>>
>> If your collection of roads is specified by means of a shapefile,
>> vignette("shapefiles") will tell you how to turn this collection into a
>> "psp" ("planar segment pattern") object; the function (method)
>> as.linnet.psp() can then be used to turn the "psp" object into a
>> "linnet" object.
>>
>> HTH
>>
>> cheers,
>>
>> Rolf Turner
>>
>> --
>> Honorary Research Fellow
>> Department of Statistics
>> University of Auckland
>> Phone: +64-9-373-7599 ext. 88276
>>
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>>
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>>
>
>
> --
> Andrés D.
>


-- 
Rol~

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