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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Rhys,</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>That’s the point, they should <i><span
style='font-style:italic'>overlap</span></i> since they were created from the
same linear reference system and the road segment ‘<i><span
style='font-style:italic'>contains</span></i>’ the curve. </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>I also tried with <i><span
style='font-style:italic'>intersects</span></i> but the problem is that it
picks up more segments than I need. For example if a curve ends at the same
point than a road segment; theoretically, the overlaps should pick up only that
segment while <i><span style='font-style:italic'>intersects</span></i> pick
also the following segment that starts when the previous segment ends. Think
also in a situation where a road intersection is located in a curve: <i><span
style='font-style:italic'>intersects </span></i>will select the other segments
that converge in the intersection even though they have no curves.</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Now, I might be misinterpreting what the
overlap should do; if this is the case please let me know.</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thanks.</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Jonathan Aguero Valverde</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Research Assistant and Ph.D. Candidate</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Pennsylvania State </span></font><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>University</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>The Pennsylvania Transportation Institute</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>201 Transportation Research Building</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>University Park, PA </span></font><font
size=2 color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'>16802</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><a href="www.personal.psu.edu/jua130">www.personal.psu.edu/jua130</a></span></font></p>
</div>
<p class=MsoNormal style='margin-left:.5in'><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style='font-weight:bold'>From:</span></b>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <b><span
style='font-weight:bold'>On Behalf Of </span></b>Rhys Stewart<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, July 03, 2007 3:32
PM<br>
<b><span style='font-weight:bold'>To:</span></b> PostGIS Users Discussion<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [postgis-users]
Problem with overlay</span></font></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'> </span></font></p>
<p class=MsoNormal style='margin-right:0in;margin-bottom:12.0pt;margin-left:
.5in'><font size=3 face="Times New Roman"><span style='font-size:12.0pt'>Ahoy
there,<br>
<br>
Well they don't overlap, they intersect. Had a similar problem and realized
that a geometry that intersects doesn't necessarily overlap.use relate to see
how the two geometries interact.<br>
If you can find out how to decipher the output from the relate command drop me
a line, cuz i cant find it anywhere on the net. <br>
<br>
SELECT road_id, relate(b.the_geom,a.the_geom) FROM road_segments a, curves b
WHERE a.the_geom && b.the_geom AND <b><span style='font-weight:bold'>intersects</span></b>(a.the_geom,
b.the_geom);<br>
<br>
road_id | relate <br>
---------+-----------<br>
10 | 1FFF0FFF2 <<< the original
row<br>
10 | 1F1F00102 <<<
modified the original row so this row overlaps.<br>
(2 rows)<br>
<br>
SELECT road_id, relate(b.the_geom ,a.the_geom) FROM road_segments a, curves b
WHERE a.the_geom && b.the_geom AND <b><span style='font-weight:bold'>overlaps</span></b>(a.the_geom,
b.the_geom);<br>
road_id | relate<br>
---------+-----------<br>
10 | 1F1F00102 <<< modified the
original row so this row overlaps. <br>
(1 row)<br>
<br>
<br>
hope that helps<br>
<br>
Rhys<br>
<br>
<br>
</span></font></p>
<div>
<p class=MsoNormal style='margin-left:.5in'><span class=gmailquote><font
size=3 face="Times New Roman"><span style='font-size:12.0pt'>On 7/3/07, <b><span
style='font-weight:bold'>Jonathan Aguero</span></b> <<a
href="mailto:jua130@psu.edu">jua130@psu.edu</a>> wrote: </span></font></span></p>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Mark,<br>
Thanks for your answer, here it is the sql you request<br>
CREATE TABLE lrs2 (gid int4, road_inv varchar(4)); <br>
SELECT AddGeometryColumn('lrs2', 'the_geom', 2927, 'LINESTRINGM', 3);<br>
INSERT INTO LRS2 (gid,road_inv, the_geom) VALUES<br>
(1, '290', GeomFromText('LINESTRINGM(2406383.283 861534.851 0.07,2406359.112<br>
861586.107 0.082,2406335.853 861620.089 0.091,2406310.002 861656.69<br>
0.101,2406255.656 861722.092 0.12,2406212.863 861767.807 0.133,2406167.562<br>
861808.508 0.147,2405858.946 862103.134 0.24,2405700.764 862300.136<br>
0.26,2405597.455 862454.556 0.313,2405561.594 862504.091 0.33,2405526.644<br>
862606.293 0.35,2405376.043 863080.764 0.444,2405107.283 863988.701<br>
0.622,2405089.364 864074.548 0.639,2405083.673 864156.245 0.654,2405087.106<br>
864240.691 0.67,2405115.272 864242.612 0.675,2405814.858 864282.694<br>
0.8,2406187.349 864301.081 0.869,2407373.155 864345.473 1.09,2408850.001<br>
864414.309 1.37,2409646.552 864450.813 1.522,2409724.132 864459.6<br>
1.537,2409866.429 864498.596 1.565,2410149.525 864603.864 1.623,2410692.582<br>
864788.24 1.733,2411535.108 865067.94 1.902,2411877.4 865184.391<br>
1.971,2411997.555 865229.746 1.996,2412066.702 865258.947 2.01 ,2412122.725<br>
865291.502 2.022,2412189.604 865347.555 2.039,2413099.432 866096.864<br>
2.264,2413233.115 866208.772 2.297,2413337.133 866308.421 2.325,2413649.134<br>
866597.512 2.406,2414104.962 867058.318 2.53,2414174.266 867117.086<br>
2.547,2414329.433 867259.172 2.586,2414541.968 867377.955 2.631,2415561.425<br>
867898.663 2.843,2415663.666 867950.203 2.865,2415711.381 867964.733<br>
2.874,2415760.712 867974.327 2.883,2415834.682 867983.789 2.897,2415954.61<br>
867986.436 2.919,2417079.882 868026.214 3.128,2417170.24 868029.877<br>
3.145,2417195.169 868042.176 3.15,2417721.664 868392.441 3.27,2417796.276<br>
868423.849 3.285,2418197.637 868559.305 3.366,2418832.192 868788.621<br>
3.495,2419543.831 869053.946 3.641,2419770.891 869135.697 3.687,2419997.995<br>
869225.542 3.733,2421265.462 869754.998 3.996,2421387.091 869796.842<br>
4.021,2421476.281 869826.718 4.038,2421571.488 869846.445 4.057,2421664.639<br>
869860.112 4.075,2421870.976 869869.151 4.115,2422422.273 869893.302<br>
4.22,2423118.185 869912.227 4.351,2423322.658 869910.882 4.39,2423543.675<br>
869887.113 4.432,2423761.002 869840.387 4.474,2423900.347 869825.931<br>
4.5,2425047.751 869848.138 4.717,2425262.25 869851.04 4.757,2425349.276<br>
869854.623 4.773,2425426.24 869868.376 4.788,2425559.956 869900.037<br>
4.814,2425663.321 869931.861 4.834,2425807.25 869981.679 4.863 ,2427651.83<br>
870598.722 5.23,2428262.085 870816.397 5.353,2430198.032 871483.911<br>
5.74,2431505.587 871940.293 6,2432815.135 872390.593 6.26,2435415.059<br>
873293.352 6.78,2437780.605 874089.52 7.257,2437820.359 874103.312 <br>
7.265,2438045.344 874181.343 7.31,2438366.008 874269.892 7.373,2438966.15<br>
874475.042 7.494,2440234.314 874916.234 7.749,2442988.007 875863.599<br>
8.303,2443271.918 875961.321 8.36,2443560.018 876049.762 8.416,2443608.255 <br>
876068.505 8.426,2443666.681 876097.327 8.438,2443732.747 876133.708<br>
8.452,2443788.707 876175.211 8.465,2444125.925 876459.689 8.546,2444432.057<br>
876711.694 8.62,2444631.05 876873.741 8.672,2444787.543 877000.844 <br>
8.712,2444943.989 877119.08 8.751,2445073.637 877200.723 8.782,2445208.325<br>
877277.273 8.813,2445344.218 877342.415 8.843,2445453.449 877396.299<br>
8.868,2445811.841 877539.109 8.945,2445825.476 877557.714 8.95,2445938.059 <br>
877587.195 8.972,2446085.112 877622.033 9,2446299.084 877660.47<br>
9.04,2446608.007 877688.501 9.098,2447923.128 877847.699 9.346,2448425.232<br>
877912.299 9.44,2452388.897 878388.295 10.2,2452678.1 878436.029<br>
10.26 ,2452785.541 878453.306 10.28,2452839.486 878461.985 10.29,2452936.212<br>
878477.791 10.309,2453147.417 878512.326 10.35,2453203.975 878520.16<br>
10.361,2453529.509 878565.275 10.424,2453718.67 878587.397 10.46,2454143.639 <br>
878624.842 10.541,2454592.191 878672.24 10.628,2454813.568 878695.375<br>
10.67,2455810.625 878816.796 10.861,2456783.057 878923.353<br>
11.046,2457948.075 879068.144 11.269,2459000.96 879187.493 11.47,2459503.893<br>
879234.27 11.566,2459785.345 879264.009 11.619,2460056.408 879299.012<br>
11.671,2460426.624 879367.34 11.743,2460854.335 879471.822<br>
11.826,2461219.594 879587.06 11.899,2462427.66 879986.859 12.14,2463875.818<br>
880473.917 12.43 ,2464522.953 880697.024 12.558,2465634.74 881112.965<br>
12.78,2466133.525 881277.739 12.86,2466464.64 881418.43 12.931,2468377.709<br>
882145.196 13.333,2469223.238 882450.574 13.51,2470998.744 883136.062<br>
13.871,2471904.723 883482.827 14.055,2472282.975 883623.285<br>
14.132,2474415.388 884367.481 14.56,2476883.851 885294.585<br>
15.057,2477619.048 885577.557 15.205,2478111.881 885802.791<br>
15.307,2478588.523 886044.39 15.408,2479003.256 886276.557 <br>
15.497,2479643.615 886689.823 15.641,2479954.098 886909.531<br>
15.713,2482447.575 888637.839 16.284,2483535.9 889406.806 16.535,2484758.36<br>
890295.507 16.82,2485433.873 890812.227 16.982,2486278.785 891394.59<br>
17.177 ,2486869.777 891816.656 17.315,2487564.761 892296.149<br>
17.475,2488317.986 892821.017 17.649,2489120.621 893384.276<br>
17.836,2489836.725 893868.926 18,2491205.446 894830.469 18.31)', 2927<br>
));<br>
<br>
CREATE TABLE road_segments (road_id int4, road_inv varchar(4),begmp real, <br>
endmp real);<br>
SELECT AddGeometryColumn('road_segments', 'the_geom', 2927, 'LINESTRING',<br>
2);<br>
INSERT INTO road_segments (road_id,road_inv, begmp, endmp) VALUES<br>
(10, '290', 1.48 , 1.79);<br>
UPDATE road_segments SET the_geom =<br>
force_2d(locate_between_measures(lrs2.the_geom,begmp,endmp))<br>
FROM lrs2;<br>
<br>
CREATE TABLE curves (curve_id int4, road_inv varchar(4),begmp real, endmp<br>
real);<br>
SELECT AddGeometryColumn('curves', 'the_geom', 2927, 'LINESTRING', 2); <br>
INSERT INTO curves (curve_id,road_inv, begmp, endmp) VALUES<br>
(100, '290', 1.48, 1.79);<br>
UPDATE curves SET the_geom =<br>
force_2d(locate_between_measures(lrs2.the_geom,begmp,endmp))<br>
FROM lrs2;<br>
<br>
SELECT road_id FROM road_segments, curves <br>
WHERE road_segments.the_geom && curves.the_geom AND<br>
overlaps(road_segments.the_geom, curves.the_geom);<br>
<br>
<br>
<br>
The last SELECT is returning null in my system which means GEOS is failing<br>
to detect the overlap. <br>
<br>
Jonathan Aguero Valverde<br>
Research Assistant and Ph.D. Candidate<br>
Pennsylvania State University<br>
The Pennsylvania Transportation Institute<br>
201 Transportation Research Building<br>
University Park, PA 16802 <br>
<a href="http://www.personal.psu.edu/jua130">www.personal.psu.edu/jua130</a><br>
<br>
-----Original Message-----<br>
From: <a href="mailto:postgis-users-bounces@postgis.refractions.net">postgis-users-bounces@postgis.refractions.net
</a><br>
[mailto:<a href="mailto:postgis-users-bounces@postgis.refractions.net">postgis-users-bounces@postgis.refractions.net</a>]
On Behalf Of Mark<br>
Cave-Ayland<br>
Sent: Monday, July 02, 2007 5:45 PM<br>
To: PostGIS Users Discussion <br>
Subject: Re: [postgis-users] Problem with overlay<br>
<br>
On Sat, 2007-06-30 at 14:05 -0400, Jonathan Aguero wrote:<br>
> Listers<br>
><br>
> I got a multilinestringM shape that I loaded into postgis without<br>
> problem (LRS). Then I used the linear referencing functions to create <br>
> the segments and curves tables from the tables (BTW, these linear<br>
> referencing functions rock!!!!). Now, my problem is that when I tried<br>
> to join the information on curves into the segments table using the <br>
> overlay function, it failed to detect several curves. Note that both<br>
> geometries (segments and curves) are generated from the same base<br>
> lines (LRS), therefore all curves should overlay one or more segments. <br>
> I am guessing I encountered a precision problem on GEOS but I wonder<br>
> whether my guess is correct and if there is any solution (maybe<br>
> snaptogrid).<br>
><br>
> Thanks in Advance for your help<br>
><br>
> PS:<br>
><br>
> OS: Windows XP<br>
><br>
> PGSQL: PostgreSQL 8.2.3 on i686-pc-mingw32, compiled by GCC gcc.exe<br>
> (GCC) 3.4.2 (mingw-special)<br>
><br>
> Postgis: 1.2<br>
><br>
> GEOS: 3.0.0rc4-CAPI-1.3.3 <br>
><br>
><br>
><br>
><br>
><br>
> Jonathan Aguero Valverde<br>
><br>
> Research Assistant and Ph.D. Candidate<br>
><br>
> Pennsylvania State University<br>
><br>
> The Pennsylvania Transportation Institute <br>
><br>
> 201 Transportation Research Building<br>
><br>
> University Park, PA 16802<br>
><br>
> <a href="http://www.personal.psu.edu/jua130">www.personal.psu.edu/jua130</a><br>
<br>
<br>
Hi Jonathan,<br>
<br>
Not sure about whether I can help you, however we need a concrete test <br>
case to able to determine whether this is a bug or not. Basically an SQL<br>
file containing a couple of tables containing some sample geometries<br>
along with the join you are using would be a great help.<br>
<br>
<br>
Kind regards, <br>
<br>
Mark.<br>
<br>
--<br>
ILande - Open Source Consultancy<br>
<a href="http://www.ilande.co.uk">http://www.ilande.co.uk</a><br>
<br>
<br>
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