Created
January 10, 2016 15:36
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PostGIS New LinestringZ from Linestring w/Raster Sample
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/* | |
We have to build a new replacement LinestringZ rather than use | |
ST_SetPoint() since UPDATE can only change a single row, and | |
the column type in question is LinestringZ, not PointZ. | |
*/ | |
select st_astext(st_makeline( | |
array(select st_makepoint(st_x(point), st_y(point), z) as new_point | |
from | |
(select st_pointn(wkb_geometry, point_idx) as point, | |
st_value(rast, st_pointn(wkb_geometry, point_idx)) as z | |
from vermont.roads, vermont.elevation_test, | |
(select ogc_fid, generate_series(1, st_numpoints(wkb_geometry)) as point_idx | |
from vermont.roads | |
where ogc_fid=92884) as point_idxs | |
where roads.ogc_fid = point_idxs.ogc_fid | |
) as points | |
) | |
)) |
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