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

[Andres Diaz Loaiza]

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.

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