Re: [UrbanSim-Users] algorithm for evaluating development constraints

Okay, thing makes a lot more sense now! This leads to a request for
an improvement of the manual: mark all of the datasets/tables that are
no longer used by the model as being deprecated? This would make the
documentation a lot more helpful.

Thanks,

Brian

On May 29, 2008, at 11:12 AM, Liming Wang wrote:

> Brian,
> Development_type is a legacy of the old transition type of develop
> model (in java version). You're right that it is not used in the
> new DPLCM, and only used in the land price model of the gridcell
> version of UrbanSim to define submodels. We totally phase it out in
> the parcel version.
>
> Liming.
>
> On Thu, May 29, 2008 at 5:59 AM, Brian Miles <Brian.Miles_at_uvm.edu>
> wrote:
>
> Liming,
>
> This helps. One thing I still don't understand is: what is the
> relationship between development types and development constraints
> for DPLCMs?
>
> >From your explanation below, and my reading of the documentation/
> source code, I don't see where development types are used at all.
>
> Thanks,
>
> Brian
>
>
> On May 20, 2008, at 3:19 PM, Liming Wang wrote:
>
> Brian,
> The order of the constraints in the table doesn't matter. For a
> given gridcell, it'll first match constraints in development
> _constraints table that are applicable to it according to attributes
> with matched names in both tables" (plan_type_id, is_in_wetland,
> etc), then the most restrictive rule, i.e. the highest minimum
> values and the lowest maximum values among applicable constraints,
> applies for each type of restrictions (units, commercial_sqft and
> industrial_sqft).
>
> The implementation of the constraints is in the urbansim/datasets/
> gridcell_dataset.py, which is called in the capacity variables
> (urbansim.gridcell.developable_maximum_commercial_sqft and
> developable_minimum_commercial_sqft, etc) of the development project
> location choice model.
>
> Hope this helps.
> Liming.
>
> On Fri, May 16, 2008 at 11:25 AM, Brian Miles <Brian.Miles_at_uvm.edu>
> wrote:
>
> Hello,
>
> We're working on some scenarios and we need to understand how
> development constraints are evaluated so that we can interpret the
> results we are seeing.
>
> The documentation in the manual for this is thin. One thing we are
> wondering is, does the order in which constraints are listed in the
> table have any bearing on what development is allowed in a given
> gridcell?
>
> Could you point out where in the location choice model code
> development constraints are evaluated?
>
> Thanks,
>
> Brian
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Received on Thu May 29 2008 - 08:25:56 PDT