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

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 - 08:12:52 PDT