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Mike! Sorry to disappoint but at the moment standard graph theory has not yet got to the point of defining 'local' status ( to use the Harary/Buckley term for total depth ) so radius 3 has no 'standard term'. So the normalizations (RA) don't have an equal either. There for concepts like intelligibility also have no matching 'standard term'. I've been doing a literature search. While its not impossible that the terms might have been independently generated in graph theory, they do not yet appear to have done so ( I could be wrong). I'm sure its just a matter of time. Its possible the social network people might have had the concept of a restricted group ( not an area I have searched ) so an alternative term might have appeared there. They seem to have done most of the core work in this kind of graph theory. One interesting observation which emerged from a Phd meeting from Shinichi Iida recently is the apparent difference between the definition of the concept of 'Betweenness' ( from Social network people) and 'Choice' ( the space syntax term) . While most people have thought the concept is identical it emerges there is a critical mathematical difference which may in some graphs give different results. As such the concept of 'choice' is different and needs a separate term to define it. Perhaps you or someone could suggest a journal which might accept a paper which would introduce and define the space syntax terms for the rest of graph community. sheep ps for those who ave been interested in the dry academic definitions of the terms. I've been working on some alternatives to radius including 'vicinity' and 'decay'. They are mathematically simpler than RA/Radius but work in similar ways. If you are interested I would be happy to email more information. >this conversation is almost making me look at my >own software - I have always assumed that there >are many formulas in space syntax that were not >well formulated originally, and that these >issues are resolved when programmed. For example >the definition of integration in the Social >Logic of Space is not in the reciprocal form >that is needed when one speaks of high or low >integration but this gets corrected in the >software. Time for some standard graph theoretic >statements I think of all the formulas used > >Mike > >At 13:37 19/12/2005, Lucas Figueiredo wrote: > >>Hello Sheep. >> >>No one is counting from 0. A single topological step means depth 1. >>There is no topological step from a given line to itself. >> >>I know that arrays are confusing in some old programming languages (I >>also programmed in ANSI C and Pascal) and sometimes we are obliged to >>change outputs because such limitations of data structure. >> >>However, I read lots of papers using R3 and I always understood this >>radius as 3 steps away, not 2. I also think that in my MSc >>dissertation wrote that R3 (3 steps) is the local standard radius >>(which is wrong). >> >>These things (interpretations, implementations) must be clear. >> >>That is why I reinforce that academic software must be properly >>published AND cited - because it is part of the methodology you use in >>experiments. I think we must put it in our software licence "cite it, >>otherwise do not use it". >> >>Regards! >>Lucas >> >> >> >>On 19/12/05, Nick Dalton <[log in to unmask]> wrote: >>> Hi the code in axman was designed to be output compatible with the >>> fortran code. as a 'C' programmer I found it an odd switch ( and >>> still do). >>> >>> People typically count from one (1,2,3,4) it's only C programmers ( >>> and their children) that count from 0. Fortran and Pascal (object >>> pascal being the language of Axman) use 1 based indexs for arrays and >>> so number systems. Everything also had to be compatible with the >>> output of the social logic of space ( with the D value). >>> >>> Zero depth makes sense to me but non programmers got there first. >>> >>> so R2 = r3, r3=r4 and r2=r1, which can be >>>said to eliminate a problem ( no r1). >>> >>> Using R2 (ie old R3 )You may noticed more glitches in radius 2 due to >> > poor micro-structure. >>> >>> sheep >>> >>> >Dear Lucas, >>> > >>> >Yes, this is the same in Depthmap: R2 is the equivalent of R3 in axman. >>> > >>> >I have always said that this makes sense: two steps away is to my >>> >mind R2, not R3. >>> > >>> >As for handling low numbers of lines within (Depthmap's) radius two, >>> >undefined values (nulls) are given in the (small number of) cases >>> >where there are too few lines to calculate RRA. >>> > >>> >Alasdair >>> > >>> >> > >Michael Batty Director Centre for Advanced Spatial Analysis (CASA) >University College London - 1-19 Torrington Place - London - WC1E 6BT UK >_______________________________________________________________ > >tel 44 (0) 207 679 1781 fax 44 (0) 207 813 2843 mobile 44 (0) 7768 423 656 > >Personal Web Page · http://www.casa.ucl.ac.uk/people/MikesPage.htm >Recent Books · Cities and Complexity · http://www.complexcity.info/ >GIS, Spatial Analysis and Modeling · http://www.casa.ucl.ac.uk/GIS/