Hi Ruben,
2009/11/3 Ruben Garnica <[log in to unmask]>:
> I have the road-centre line map of the Mexico City's Metropolitan Area and
> it has about 224,000 lines and I don't know if there is any computer capable
> to process it (rather in depthmap or confeego)
Assuming that your map has 224.000 _street segments_, which is the
standard for road-centre lines, a continuity map would reduce a map of
this size to roughly 25% of its size, i.e. 50-70k continuity lines.
The problem is that it needs to open the whole thing first, and this
might be a problem.
However, I have processed Claudia's map of the first ring of Mexico
city in my computer (a notebook with 2GB RAM), which has about the
same number of nodes (plots, rather than lines). So, in principle, it
should be OK to open, merge, and process a map of this size as a
continuity or axial map.
The problem is that, for the moment, you would be restricted to
topological/hierarchical network analysis, which applies better to
vehicular movement, as there is no software ready to process
street-segments (Mindwalk and Peponis' stuff are still experimental)
other than Depthmap.
However, If I am not mistaken (Alasdair, please correct me), Depthmap
breaks street-segments into _line-segments_, reason why the number of
nodes scales uncontrollably, requiring this sort of heaving-processing
techniques.
The other problem for analysing a map of this size in Depthmap /
Angular-segment Analysis is the projection. Since the area is just too
big (Mexico City enters three states), projecting it on a plane,
something required by both Depthmap and Mindwalk, means that the
distortions in angles / metric measures in the borders of the map are
noticeable, at least. This is actually a subject for a paper, as we
definitively need to start discussing this as our maps are getting
bigger and bigger.
If you are not in a rush, I could have a try and see if I could
process your map and return the data to you with the experimental
stuff used in my thesis.
Best Regards,
--
Lucas Figueiredo - Ph.D.
Universidade Federal do Rio Grande do Norte
Professor Visitante do Departamento de Arquitetura e Urbanismo
MUsA - Laboratório de Morfologia e Usos da Arquitetura
LATTICE - Laboratório de Tecnologias de Investigação da Cidade
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