Glad this was helpful. Below is the actual "production" version I used to test
the theory. I quickly realized with SRID 2229 (NAD83 Feet) that the 64x128
hexes were much too fine grained, so I multiplied the dimensions by 100. The
output looks like a D&D board game ;) , not that I play mind you.
=====================
create table hex_grid (gid serial not null primary key, the_geom geometry not
null);
INSERT INTO hex_grid (the_geom)
SELECT translate(the_geom, x_series, y_series)
from
generate_series(
(select min(st_xmin(the_geom))::int from geometrytable) - 12800,
(select max(st_xmax(the_geom))::int from geometrytable) + 12800, 12800
) as x_series,
generate_series(
(select min(st_ymin(the_geom))::int from geometrytable) - 12800,
(select max(st_ymax(the_geom))::int from geometrytable) + 12800, 25600
) as y_series,
(
SELECT 'POLYGON((0 0,6400 6400,6400 12800,0 19200,-6400 12800,-6400
6400,0 0))'::geometry as the_geom
UNION SELECT translate('POLYGON((0 0,6400 6400,6400 12800,0 19200,-6400
12800,-6400 6400,0 0))'::geometry, 6400, 12800) as the_geom
) as one_hex
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Martin Davis
Sent: Friday, May 30, 2008 10:12 AM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] hexagonal grid
This is great! Added to the wiki at
http://postgis.refractions.net/support/wiki/index.php?GenerateHexagonalGrid
Sufficool, Stanley wrote:
> Generate a hexagonal grid of 64x128 hexes, then follow the slice/dice
> from bostongis at step 4.
>
> Substitute the values in generate series with your datasource min/max
> X/Y extents.
>
> ===============================
>
> create table hex_grid (gid serial not null primary key, the_geom
> geometry not null);
>
> INSERT INTO hex_grid (the_geom)
> SELECT translate(the_geom, x_series, y_series)
> from generate_series(0 - 128, 10000 + 128, 128) as x_series,
> generate_series(0 - 128, 10000 + 128, 256) as y_series, (
> SELECT 'POLYGON((0 0,64 64,64 128,0 192,-64 128,-64 64,0 0))'::geometry
> as the_geom
> UNION SELECT translate('POLYGON((0 0,64 64,64 128,0 192,-64 128,-64
> 64,0 0))'::geometry, 64, 128) as the_geom
> ) as one_hex
>
> ===============================
>
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Matias Massigoge
> Sent: Thursday, May 29, 2008 12:58 PM
> To: PostGIS Users Discussion
> Subject: Re: [postgis-users] hexagonal grid
>
>
> Thanks Paul!!
>
> On Thu, May 29, 2008 at 4:42 PM, Paul Ramsey
> <[EMAIL PROTECTED]> wrote:
>
>> Try this:
>>
>> http://www.bostongis.com/blog/index.php?/archives/35-Map-Dicing-and-o
>> t
>> her-stuff.html
>>
>> P.
>>
>> On Thu, May 29, 2008 at 12:34 PM, Matias Massigoge
>> <[EMAIL PROTECTED]> wrote:
>>
>>> Hi all,
>>>
>>> I'm looking for something similar but squared.
>>> This theme have been covered in the past?
>>> Sorry, I'm newby.
>>> Thanks all.
>>>
>>> MatÃas
>>>
>>>
>>>
>>> On Thu, May 29, 2008 at 12:42 PM, Brent Wood <[EMAIL PROTECTED]>
>>> wrote:
>>>
>>>>> On Thu, May 29, 2008 at 7:08 AM, Randall, Eric
>>>>> <[EMAIL PROTECTED]>
>>>>>
>>>> wrote:
>>>>
>>>>>> Has anyone created a method for generating a hexagonal grid over
>>>>>> a polygon
>>>>>>
>>>>> envelope using postgis? Thought I'd ask before setting out.
>>>>> Thanks.
>>>>>
>>>> Hi Eric
>>>>
>>>> I haven't specifically done this in PostGIS, but have briefly
>>>> looked
>>>> into something similar with a colleague who uses R extensively, and
>>>> was looking at cellular automata modelling over a hexagonal grid. He
>>>> was using such a dataset in R, & there were a few ways this could be
>>>> transferred to PostGIS, including the R:gdal package, or a
>>>> dump/parse/reformat/import script.
>>>>
>>>> Cheers,
>>>>
>>>> Brent Wood _______________________________________________
>>>> postgis-users mailing list [email protected]
>>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>>
>>>>
>>> _______________________________________________
>>> postgis-users mailing list [email protected]
>>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>>
>>>
>> _______________________________________________
>> postgis-users mailing list [email protected]
>> http://postgis.refractions.net/mailman/listinfo/postgis-users
>>
>>
> _______________________________________________
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> _______________________________________________
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>
>
--
Martin Davis
Senior Technical Architect
Refractions Research, Inc.
(250) 383-3022
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