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@ -54,15 +54,15 @@ raster2pgsql -d -M -C -I -s 4326 -t 128x128 -F *.tif dem.srtm | psql --dbname=os
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Here's a breakdown of the above command:
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Here's a breakdown of the above command:
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- -d This drops an existing table if it already exists. It's useful to include this in case we need to run the command again.
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- `-d` This drops an existing table if it already exists. It's useful to include this in case we need to run the command again.
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- -M This runs `VACUUM ANALYZE` on the table after the raster tiles have been inserted into the database. This optimizes the table by reclaiming storage space and then collecting table statistics.
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- `-M` This runs `VACUUM ANALYZE` on the table after the raster tiles have been inserted into the database. This optimizes the table by reclaiming storage space and then collecting table statistics.
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- -C This applies raster constraints to the table by using the `AddRasterConstraints` function in PostGIS. This adds several types of constraints to the table which ensures data integrity and enforces rules for consistency.
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- `-C` This applies raster constraints to the table by using the `AddRasterConstraints` function in PostGIS. This adds several types of constraints to the table which ensures data integrity and enforces rules for consistency.
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- -I Creates a spatial index (GiST) on the table.
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- `-I` Creates a spatial index (GiST) on the table.
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- -s Assign SRID (Spatial Reference System Identifier) to the raster.
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- `-s` Assign SRID (Spatial Reference System Identifier) to the raster.
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- -t Tile size. This splits the raster into tiles of the specified size. Each tile is a row in the final table.
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- `-t` Tile size. This splits the raster into tiles of the specified size. Each tile is a row in the final table.
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- -F Creates a filename column. As the raster is split into many smaller tiles, this is useful to help us identify the original file the tile belonged to.
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- `-F` Creates a filename column. As the raster is split into many smaller tiles, this is useful to help us identify the original file the tile belonged to.
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- *.tif Selects all of the .tif files in the directory.
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- ` *.tif` Selects all of the .tif files in the directory.
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- dem.srtm Defines the schema and name of the table. Remember to create the `dem` schema in the database before running the command.
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- `dem.srtm` Defines the schema and name of the table. Remember to create the `dem` schema in the database before running the command.
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The `raster2pgsql` command will output a sql query which we can then pipe into the `psql` command.
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The `raster2pgsql` command will output a sql query which we can then pipe into the `psql` command.
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