Tom Carden wrote: > > > I believe we shouldn't have loops of any sort. routing > > > algorithms like to have straight simple topologies.
> Absolutely agree. I think ways as a data type will be pointless if > they allow loops and branches, and I've always said so. Can anybody here recommend a useful book on basic data structures and algorithms for GIS? I only have "Mapping Hacks", which shows very simple cookbook recipies that never go deep enough, and "Web Mapping Illustrated", which is a guide to using the UMN MapServer. Both are good books, but not for this purpose. Nine textbook titles are listed at the end of Wikipedia article http://en.wikipedia.org/wiki/Geographic_information_system#Textbooks Does any of these address low-level programming? A useful book would answer questions like the following. I don't need list members to answer these questions now. I need a book title that we can recommend newcomer OpenStreetMap developers to read before asking these questions. I think most newcomers will be, just like I am, good programmers with very little GIS background. - What does geoid and datum mean to cartographers? - What are different map projections used for, and how can one benefit from using PROJ.4 instead of coding the conversions from scratch? - When are vector data used and when are raster data used? How do map projection conversions apply to the two kinds of data? What "famous" algorithms exist for the two kinds? - To what extent do GIS systems use linear line segments instead of curve splines, and why? (With surprise I learned from earlier messages on this list that all use linear segments, virtually nobody uses splines.) - Why do GIS systems use line trains (polylines) instead of simple line segments? - How can MapServer be so fast in rescaling, resizing, and cropping maps when my home-written code is so slow? - How do route optimizers work, and what kind of data structures do they need? - How should overlapping roads best be represented? - How should roundabouts best be represented? - Can a street have two separate parts that aren't connected? - How can house numbers be assigned along a street, and how is that best represented in a GIS system? - How has GIS technology evolved over the last couple of decades? What is the current state of commercial and free software, and what should we expect from the coming decade? -- Lars Aronsson ([EMAIL PROTECTED]) Aronsson Datateknik - http://aronsson.se _______________________________________________ Geowanking mailing list [email protected] http://lists.burri.to/mailman/listinfo/geowanking
