History of Helsinki Noise Areas
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This table contains the version history of the base table rows extracted from the 'Helsingin kaupunkiympariston toimiala' data source. The table, named 'avoindatamelualueet_2017_14_maant_hki_lyomelualueet_2017_14_maant_hki_lyopolygonhistory', stores the historical versions of the rows and includes two additional columns: '_start_date' and '_end_date'. The '_start_date' column signifies the date when a particular row was extracted from the data source, while the '_end_date' column represents the date when a new version of the row was extracted. If the value in the '_end_date' column is null, it indicates that the row is the most recent version. The table consists of several other columns including 'id', 'db_lo', 'db_hi', 'datanomist', 'paivitetty', 'geom_geojson', 'geom_geotext', 'geom_type', 'geom_centroid', 'geom_center_x', and 'geom_center_y'. This data can be leveraged for various data analytics purposes such as identifying changes and trends over time, analyzing noise areas, and calculating centroid coordinates. The data source of this table is 'Helsinki City Environment Sector' and it originates from Finland (ISO country code: 'fi').
Field Descriptions
| Name |
Data type |
Description |
| _start_date | date | The start date of the validity period of the row version. |
|---|
| _end_date | date | The end date of the validity period of the row version. |
|---|
| _row_number | long | The number of the row version. |
|---|
| id | int | The unique identifier of the row. |
|---|
| db_lo | float | The lower part of the database value. |
|---|
| db_hi | float | The higher part of the database value. |
|---|
| datanomist | string | The name of the data analyst. |
|---|
| paivitetty | date | The date when the row was last updated. |
|---|
| geom_geojson | string | The geometry of the row in GeoJSON format. |
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| geom_geotext | string | The geometry of the row in geotext format. |
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| geom_type | string | The type of geometry of the row. |
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| geom_centroid | string | The centroid of the geometry of the row. |
|---|
| geom_center_x | double | The x-coordinate of the center of the geometry of the row. |
|---|
| geom_center_y | double | The y-coordinate of the center of the geometry of the row. |
|---|
| geom | binary | The geometrical representation of the row. |
|---|
