[postgis-users] Creating a grid purely in SQL
Mr. Puneet Kishor
punk.kish at gmail.com
Mon Mar 7 20:13:19 PST 2011
Given a top-left starting point [ulx, uly], and a cell width 'w' and height 'h', is it possible to create a table entirely in SQL populated with rows increasing from left to right up to X and top to bottom up to Y. The table schema would be something like --
CREATE TABLE cells (
cell_id INTEGER NOT NULL,
xmid DOUBLE PRECISION,
ymid DOUBLE PRECISION,
CONSTRAINT cells_pkey PRIMARY KEY (cell_id)
where xmid = (xmin + xmax) / 2 and ymid = (ymin + ymax) / 2, [xmin, ymin, xmax, ymax] being the corners of each cell.
A bonus question -- is it possible to store two geometry columns in one table? For example, if I wanted to store the geometry for both the center points [xmin, ymid] as well as the box [xmin, ymin, xmax, ymax], would that be possible? Would that even be recommended (for example, to speed up queries/drawing, etc.).
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