[pgrouting-users] Working with Driving Distance

[Roger André]

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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