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Schemaless database storage (PostGIS) with FME Hans Gunnar Steen, GIS engineer – FME Certified Professional – Norkart as.

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Presentation on theme: "Schemaless database storage (PostGIS) with FME Hans Gunnar Steen, GIS engineer – FME Certified Professional – Norkart as."— Presentation transcript:

1 Schemaless database storage (PostGIS) with FME Hans Gunnar Steen, GIS engineer – FME Certified Professional – Norkart as

2 Schemaless database storage (PostGIS) with FME  Schemas in FME  Used on “all” readers/writers regardless of format  Defines the structure of the dataset such as:  Feature Types  Attributes  Data types  More or less strict – dependent on needs  Very important when using databases.  So, why do we try to avoid it in some cases?

3 Schemaless database storage (PostGIS) with FME  Background: DOK( Det Offentlige Kartgrunnlaget)  Tematic datasets – required by law  Critical in zoning and building planning  Supports decision making in accordance with norwegian Planning and Building Act  Contains data such as flooding, landslides, avalances, proteced areas and buildings, ground conditions, minerals…  92 datasets - and growing.

4 Schemaless database storage (PostGIS) with FME  Quality, structure and distribution  Variable quality. Most datasets still not approved.  Different structure and schemas.  Different ways of distribution(download, service, phone calls…..)  Many different formats – and coordinate systems.  A hazzle to deal with   Want to collect, store, analyze and distribute from a consistent PostGIS database.

5 Schemaless database storage (PostGIS) with FME  (Relational)databases requires strich schemas.  Example flooding:  Example habitats:

6 Schemaless database storage (PostGIS) with FME  First try……

7 Schemaless database storage (PostGIS) with FME  Or….

8 Schemaless database storage (PostGIS) with FME  Problem: A lot of tables – or a lot of attributes  Need common storeage of different schemas.  MongoDB and some other DB’s allows this, but:  Lack SQL query capabilities, as data is stored in json (javascript object notation)  Very limited spatial data capabilities.  PostGIS has excellent spatial data capabilities  But need clearly defined schemas.  We need the best of both worlds, so…..

9 Schemaless database storage (PostGIS) with FME  Use Postgis for spatial storeage and json(b) for attribute storage!  1 table – 1 attribute(!) – not 1000+++…  Example:Table vs json: {"GJENTAKINT": "10", "KVALITET.MÅLEMETODE": "61", "KVALITET.NØYAKTIGHET": "36"} {"OPPDATERINGSDATO": " 201309112206", "BMVERDI": "B", "BM_TAKSON_TAKSONVITNAVN": "Alces alces"}

10 Schemaless database storage (PostGIS) with FME  FME implementation  Great json – handling in FME!  Use AttributeJSONPacker to compress to json  Use AttributeJSONUnpacker to restore from json  Extract single elements using JSONExtractor  Write to POSTGIS as regular text (improvements?)  Filter on reader side by using regular sql-syntax  select datasetid from dok.datastore where(attribs- >>'GJENTAKINT'= '20')

11 Schemaless database storage (PostGIS) with FME  Wrap-up and benefits:  No attribute renaming and schema mapping  No null or empty value storage  Supports sql queries and flexible GIN – indexing  Json is well known among programmers  Excellent json – handling in FME  Simpler SQL syntax  No errors on import due to data type mismatch.  Very flexible spatial queries.

12 Thank You!  Questions?  For more information:  hans.gunnar.steen@norkart.no  Norkart  http://www.fmepedia.com


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