I'm trying to join two PostGIS table, one of DMAs and another of states.
After getting some help, I ran this query:
CREATE TABLE combined AS SELECT nextval('polyseq_1') AS id, b.name AS state_name, a.dma_1 AS dma_1, CASE WHEN ST_Within(a.geom, b.geom) THEN a.geom ELSE ST_MULTI(ST_INTERSECTION(a.geom,b.geom)) end AS geom FROM us_states b JOIN us_dma a ON ST_INTERSECTS(a.geom, b.geom)However, the results I get have some gaps, for instance, it looks like the Dallas DMA in Texas is completely missing. I'm not familiar with PostGIS but I am unable to figure why the query will cause polygons to be missing. A picture is below:
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After getting some help, I ran this query:
CREATE TABLE combined AS SELECT nextval('polyseq_1') AS id, b.name AS state_name, a.dma_1 AS dma_1, CASE WHEN ST_Within(a.geom, b.geom) THEN a.geom ELSE ST_MULTI(ST_INTERSECTION(a.geom,b.geom)) end AS geom FROM us_states b JOIN us_dma a ON ST_INTERSECTS(a.geom, b.geom)However, the results I get have some gaps, for instance, it looks like the Dallas DMA in Texas is completely missing. I'm not familiar with PostGIS but I am unable to figure why the query will cause polygons to be missing. A picture is below:
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