[Openspace] calculating distances between points

[Julia Koschinsky]

Hi German,

Yes, if you create distance weights matrices (either distance bands or knn), then the third column in the .gwt weights file (which you can open in any text editor) contains the distance between points (first two columns are point IDs). E.g., if you choose knn=1, then the distance between each point and its closest neighbor is recorded (distance units based on input units). 

Note that GeoDa currently doesn't take these distance values into account beyond assigning neighbors into 0,1 categories.

Julia

---- Original message ----
>Date: Sat, 10 Nov 2007 17:51:03 -0800 (PST)
>From: "German M. Izon" <g_mizon at yahoo.com>  
>Subject: Re: [Openspace] GeoDa quesitons  
>To: koschins at uiuc.edu
>
I would like to know if I can calculate the distance between two points in GeoDa. I have the x-y coordinates.
>
>   Thanks!
>   German.
>
>   Julia Koschinsky <koschins at uiuc.edu> wrote:
>
>     yes, here:
>     http://www.sal.uiuc.edu/tools/tools-sum/rgeo/rgeo-detail/areal-lattice-data-analysis-packages-on-cran
>
>     julia
>
>     ---- Original message ----
>     >Date: Sat, 10 Nov 2007 13:15:36 -0800 (PST)
>     >From: "German M. Izon" <g_mizon at yahoo.com>
>     >Subject: Re: [Openspace] GeoDa quesitons
>     >To: koschins at uiuc.edu
>     >
>     > Great! Thank you.
>     > Do you know if the R package is available on the
>     > internet?
>     >
>     > German.
>     >
>     > Julia Koschinsky <koschins at uiuc.edu> wrote:
>     >
>     > 1) Yes, Geoda automatically row-standaridzes the
>     > weights matrix in the spatial regression models.
>     >
>     > 2) The Lagrange Multiplier test to distinguish
>     > between the lag and error alternatives is in the
>     > "Diagnostics of Spatial Dependence" output for
>     > your OLS model when you specify a weights
>     matrix.
>     >
>     > 3) No. R's spdep package is one of the free
>     > options for running a spatial 2SLS model.
>     >
>     > Julia
>     >
>     > ---- Original message ----
>     > >Date: Sat, 10 Nov 2007 12:34:29 -0700
>     > >From: "German Muchnik Izon" <german at unm.edu>
>     > >Subject: [Openspace] GeoDa quesitons
>     > >To: openspace at sal.uiuc.edu
>     > >
>     > >Hi,
>     > >
>     > >I have recently found the GeoDa software and I
>     > have the
>     > >following questions.
>     > >
>     > >1)Let's that I create a weight matrix using
>     > GeoDa. Does
>     > >GeoDa automatically row-normalize this matrix
>     > when, for
>     > >instance, I run a spatial-lag model?
>     > >
>     > >2)I run a spatial-lag model using GeoDa and I
>     > could not
>     > >find a Lagrange Multiplier error test in the
>     > output. Can I
>     > >get such a test using GeoDa?
>     > >
>     > >3)Can I run a spatial 2-SLS model in GeoDa?
>     > >
>     > >Thank you a lot for your help!
>     > >
>     > >German.
>     > >University of New Mexico
>     > >_______________________________________________
>     > >Openspace mailing list
>     > >Openspace at sal.uiuc.edu
>     > >http://sal.uiuc.edu/mailman/listinfo/openspace
>     > </german at unm.edu>
>     >
>     >
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