[pgrouting-users] Working with Driving Distance

[Roger André]

Hi Daniel,

Thanks for your reply.  I checked, and it appears that I have that wrapper
function installed.  Here is what my pgrouting install dir looks like:

$ pwd
/usr/local/pgrouting-1.05/extra/driving_distance/sql

$ ll
total 36
drwxr-xr-x 3 15036 users 4096 2010-12-21 15:58 ./
drwxr-xr-x 5 15036 users 4096 2010-12-21 15:58 ../
drwxr-xr-x 2 root  root  4096 2010-12-21 15:58 CMakeFiles/
-rw-r--r-- 1 root  root  1811 2010-12-21 15:58 cmake_install.cmake
-rw-r--r-- 1 15036 users  134 2010-11-16 18:42 CMakeLists.txt
-rw-r--r-- 1 root  root  5540 2010-12-21 15:58 Makefile
-rw-r--r-- 1 15036 users 1757 2010-11-16 18:42 routing_dd.sql
-rw-r--r-- 1 15036 users 3790 2010-11-16 18:42 routing_dd_wrappers.sql

And I did make sure to run both SQL files against the database my roads are
stored in.

  482  psql -d eligibility -f routing_dd.sql
  483  psql -d eligibility -f routing_dd_wrappers.sql
  490  psql -d eligibility -f routing_tsp.sql
  491  psql -d eligibility -f routing_tsp_wrappers.sql

I will review your usage instructions and see if I'm missing anything.

Roger
--

On Tue, Dec 21, 2010 at 5:51 PM, Daniel Kastl <daniel at georepublic.de> wrote:

> Hi Roger,
>
> You're using the "core" function, I think.
> You could use the driving_distance wrapper function, which will return you
> a polyogon.
> For that you need to load this SQL:
> https://github.com/pgRouting/pgrouting/blob/master/extra/driving_distance/sql/routing_dd_wrappers.sql
> You can also find it in the directory where the other pgRouting SQL files
> are.
>
> The function will take these parameters then:
>
> driving_distance(table_name varchar, x double precision, y double
> precision,
>         distance double precision, cost varchar, reverse_cost varchar,
> directed boolean, has_reverse_cost boolean)
>
> X,Y are the coordinates you take as a center point.
> You can take the returned polygon then and do other spatial queries.
>
> Best regards,
> Daniel
>
>
>
> 2010/12/22 Roger André <randre at gmail.com>
>
>> Hi All,
>>
>> I need to generate some maps that show all of the road segments that are
>> within a certain distance of specific points.  I have been able to generate
>> some answers using the driving_distance function, but am not sure what to do
>> with them.  Here's what I get:
>>
>> # SELECT * FROM driving_distance('SELECT gid AS id, source, target,
>> length::double precision AS cost FROM edges',49,2000,false,false);
>>  vertex_id | edge_id |       cost
>> -----------+---------+------------------
>>         15 |       9 | 1854.34547361565
>>         20 |     104 | 1549.85630678904
>>         22 |      68 | 858.367668935802
>>         23 |     125 | 1466.02479201359
>>         24 |      75 | 801.137871846872
>>         25 |     125 | 1169.02817170106
>>         26 |     106 | 1296.98197602289
>>         48 |      71 | 902.595810873304
>>         49 |     106 |                0
>>         51 |      74 | 1948.07551810288
>>         52 |      75 | 1620.93404864578
>> (11 rows)
>>
>> These answers seem legit, but I'm not sure what to do with them.
>> Ultimately, I need to show both the minimum enclosing polygon that
>> "surrounds" all of the road segments, as well as the road segments
>> themselves.  Can someone please give me some pointers as to what I can do to
>> accomplish this?
>>
>> Thanks,
>>
>> Roger
>> --
>>
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>>
>>
>
>
> --
> Georepublic UG & Georepublic Japan
> eMail: daniel.kastl at georepublic.de
> Web: http://georepublic.de
>
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