[postgis-users] contains function with complex polygons
Gilbert, Antoine
AGilbert at korem.com
Thu Sep 28 07:39:28 PDT 2006
Yes, Thank You.
My understanding of complex polygons (postgis, ogc) was wrong.
I was used to the object model of another software I'm using who is not
ogc compliant.
-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Emily Gouge
Sent: September 27, 2006 5:51 PM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] contains function with complex polygons
try making the nested hole a separate polygon:
MULTIPOLYGON (((-128.74153099999998 66.42965, -106.554262 32.849587,
-130.846486 40.578899,
-152.378198 61.006418999999994, -128.74153099999998 66.42965)),
((-64.841883 75.565074, -48.866971
72.139282, -39.750806 62.662659999999995, -27.604758 32.297475999999996,
-77.997723
27.889585999999998, -96.791707 62.14741, -64.841883 75.565074),
(-57.793946999999996 70.71189,
-64.841883 72.710258, -85.985179 63.860305999999994, -70.11599
56.037586999999995,
-54.035098999999995 59.578098, -57.793946999999996 70.71189),
(-41.407126 47.204051,
-49.688469999999995 39.474706999999995, -34.781974 36.162130999999995,
-41.407126 47.204051)),
((-65.311643 60.434546, -72.82933899999999 60.720017999999996,
-76.11817099999999 65.28773,
-71.419803 67.000626, -64.371867 68.428018, -61.552794999999996
64.431282, -65.311643 60.434546)))
----
select isvalid(geomfromtext('MULTIPOLYGON (((-128.74153099999998
66.42965, -106.554262 32.849587,
-130.846486 40.578899, -152.378198 61.006418999999994,
-128.74153099999998 66.42965)), ((-64.841883
75.565074, -48.866971 72.139282, -39.750806 62.662659999999995,
-27.604758 32.297475999999996,
-77.997723 27.889585999999998, -96.791707 62.14741, -64.841883
75.565074), (-57.793946999999996
70.71189, -64.841883 72.710258, -85.985179 63.860305999999994, -70.11599
56.037586999999995,
-54.035098999999995 59.578098, -57.793946999999996 70.71189),
(-41.407126 47.204051,
-49.688469999999995 39.474706999999995, -34.781974 36.162130999999995,
-41.407126 47.204051)),
((-65.311643 60.434546, -72.82933899999999 60.720017999999996,
-76.11817099999999 65.28773, -7
1.419803 67.000626, -64.371867 68.428018, -61.552794999999996 64.431282,
-65.311643 60.434546)))'));
isvalid
---------
t
(1 row)
select contains(geomfromtext('MULTIPOLYGON (((-128.74153099999998
66.42965, -106.554262 32.849587,
-130.846486 40.578899, -152.378198 61.006418999999994,
-128.74153099999998 66.42965)), ((-64.841883
75.565074, -48.866971 72.139282, -39.750806 62.662659999999995,
-27.604758 32.297475999999996,
-77.997723 27.889585999999998, -96.791707 62.14741, -64.841883
75.565074), (-57.793946999999996
70.71189, -64.841883 72.710258, -85.985179 63.860305999999994, -70.11599
56.037586999999995,
-54.035098999999995 59.578098, -57.793946999999996 70.71189),
(-41.407126 47.204051,
-49.688469999999995 39.474706999999995, -34.781974 36.162130999999995,
-41.407126 47.204051)),
((-65.311643 60.434546, -72.82933899999999 60.720017999999996,
-76.11817099999999 65.28773,
-71.419803 67.000626, -64.371867 68.428018, -61.552794999999996
64.431282, -65.311643
60.434546)))'), geomfromtext('POINT (-68.5167 63.7500)'));
contains
----------
t
(1 row)
Gilbert, Antoine wrote:
> How I can make this polygon valid?
>
> It's a very simple one
>
> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net
> [mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
> Emily Gouge
> Sent: September 27, 2006 4:29 PM
> To: PostGIS Users Discussion
> Cc: Vachon, Patrick
> Subject: Re: [postgis-users] contains function with complex polygons
>
> This may be a result of the polygon not being a valid PostGIS polygon.
> When I ran an isvalid() on
> the polygon geometry it returned false with the notice "Holes are
> nested".
>
> SELECT isvalid(geomfromtext('MULTIPOLYGON(...)'));
> NOTICE: Holes are nested
> isvalid
> ---------
> f
> (1 row)
>
>
> Emily
>
>
> Gilbert, Antoine wrote:
>> Hi
>>
>>
>>
>> I have special case problem with the contains SQL function if I use
>> polygons with "island in a hole"
>>
>>
>>
>> For example I have a polygon, with a lake in it (hole) and an island
> in
>> the middle of the lake, all these as a whole polygon.
>>
>>
>>
>> I have a point location standing on the island.
>>
>>
>>
>> Why the contains SQL function contains(myPolygon,myPoint) dosen't
> return
>> true for my point
>>
>>
>>
>> I verified my geometries using JUMP and everything seems ok
>>
>>
>>
>> Here is the point: POINT (-68.5167 63.7500)
>>
>>
>>
>> Here is my complex polygon (multipolygon in fact)
>>
>>
>>
>> MULTIPOLYGON(((-128.74153099999998 66.42965, -106.554262 32.849587,
>> -130.846486 40.578899, -152.378198 61.006418999999994,
>> -128.74153099999998 66.42965)),((-64.841883 75.565074, -48.866971
>> 72.139282, -39.750806 62.662659999999995, -27.604758
> 32.297475999999996,
>> -77.997723 27.889585999999998, -96.791707 62.14741, -64.841883
>> 75.565074),(-57.793946999999996 70.71189, -64.841883 72.710258,
>> -85.985179 63.860305999999994, -70.11599 56.037586999999995,
>> -54.035098999999995 59.578098, -57.793946999999996
> 70.71189),(-41.407126
>> 47.204051, -49.688469999999995 39.474706999999995, -34.781974
>> 36.162130999999995, -41.407126 47.204051),(-65.311643 60.434546,
>> -72.82933899999999 60.720017999999996, -76.11817099999999 65.28773,
>> -71.419803 67.000626, -64.371867 68.428018, -61.552794999999996
>> 64.431282, -65.311643 60.434546)))
>>
>>
>>
>> Formatted version:
>>
>>
>>
>> MULTIPOLYGON (((
>>
>> -128.74153099999998 66.42965,
>>
>> -106.554262 32.849587,
>>
>> -130.846486 40.578899,
>>
>> -152.378198 61.006418999999994,
>>
>> -128.74153099999998 66.42965
>>
>> )), ((
>>
>> -64.841883 75.565074,
>>
>> -48.866971 72.139282,
>>
>> -39.750806 62.662659999999995,
>>
>> -27.604758 32.297475999999996,
>>
>> -77.997723 27.889585999999998,
>>
>> -96.791707 62.14741,
>>
>> -64.841883 75.565074
>>
>> ), (
>>
>> -57.793946999999996 70.71189,
>>
>> -64.841883 72.710258,
>>
>> -85.985179 63.860305999999994,
>>
>> -70.11599 56.037586999999995,
>>
>> -54.035098999999995 59.578098,
>>
>> -57.793946999999996 70.71189
>>
>> ), (
>>
>> -41.407126 47.204051,
>>
>> -49.688469999999995 39.474706999999995,
>>
>> -34.781974 36.162130999999995,
>>
>> -41.407126 47.204051
>>
>> ), (
>>
>> -65.311643 60.434546,
>>
>> -72.82933899999999 60.720017999999996,
>>
>> -76.11817099999999 65.28773,
>>
>> -71.419803 67.000626,
>>
>> -64.371867 68.428018,
>>
>> -61.552794999999996 64.431282,
>>
>> -65.311643 60.434546
>>
>> )))
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
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