STANDARDS

Today the general advantages with using standards in different technical fields are fairly understood by most people. Still, when identifying types of standards needed for a facility like a Spatial Data Infrastructure, it is not obvious which kind of standards are appropriate, which standards exist or how to implement them in the SDI. Looking over the whole concept of a SDI gives a variety of standards on different levels covering everything from Cabling and Electrical Interfaces to Map Presentation. In this very first stage of the establishment, we will focus on a few.

Data Format and Exchange

This covers the logical and physical structure of spatial data and capabilities for access and exchange of spatial data among multiple computer platforms and applications. Historically, there have been two strategies to solve the exchange:

1. Development of specific programs to translate formats directly from one system to another.

2. Translation of a specific vendor format to an accepted intermediate exchange format followed by another translation to other vendor’s formats.

There are several standards for exchange formats in existence – following strategy number 2 above – including DXF and IGES (Interactive Graphics Exchange standard). If within the scope there is any kind of software standard, the task of defining exchange standards could be as easy as applying that software’s exchange format, e.g. e00 and Shape files for ESRI software.

Metadata

A metadatabase for a structure as complex as a SDI, must be able to give information about data in different systems and formats. Even if there is data that is not included in the SDI (due to format quality etc) it is still of importance to collect data into a metadatabase. Collecting and presenting data from different systems and formats really puts requirements on the metadata to be in a specific, standardised way. Standards for metadata have been dealt with for a long time and there are already some well-accepted standards (ISO, FGDC amongst others).

Software

Although there are no international software standards today, it could still be an idea to standardise software within an SDI. It is important though to understand the difference between a standard on how to develop or create the software and the software itself. One specific software could base it’s data on standardised database schemas and use other standardised ways to develop the software, but the software itself will never be a standard. For practical reasons it could be convenient for an SDI to define one common or recommended software to be used. It would make data exchange and access between different organisations easier. The drawback is that users already using other software or systems will not be able to assimilate all the advantages that the SDI brings.

Standardisation Bodies

There are a number of organisations dealing with the issue of standards with regards to spatial data. They work partly in parallel but have the same aim – to establish well-accepted standards for geographic information. Two of the most powerful organizations are ISO (International Organisation for Standardisation) and its ISO 19 100 Geographic Information and OGC– Open Geospatial Consortium.

These standards cover methods, tools and services for management, acquiring, processing, analysing, accessing, presenting and transfering of GI data. Although similar and working very much in a co-operative way, they differ slightly in their mandate. ISO 19 100 – i.e. the ISO series of standards for Geographic Information – aims at securing standardised processes for both development and deployment whilst OGC is more focused on integrating the geospatial data and geoprocessing resources into the mainstream computing.

The ISO 19100 family consists of:

SO 19101 - Reference model
ISO 19102– Overview
ISO 19103 - Conceptual schema language
ISO 19104 – Terminology
ISO 19105 - Conformance and testing
ISO 19106 – Profiles
ISO 19107 - Spatial schema
ISO 19108 - Temporal schema
ISO 19109 - Rules for application schema
ISO 19110 - Feature cataloguing methodology
ISO 19111 - Spatial referencing by co-ordinates
ISO 19112 - Spatial referencing by geographic identifiers
ISO 19113 - Quality principles
ISO 19114 - Quality evaluation procedures
ISO 19115 – Metadata. Additional material in OGC document 01-111
ISO 19116 - Positioning services
ISO 19117 – Portrayal
ISO 19118 – Encoding
ISO 19119 – Services
ISO 19120 - Amendment 1 Geographic information - Functional standards
ISO/TR 19121 - Imagery and gridded data
ISO/TR 19122 - Qualifications and certification of personnel
ISO 19123 - Schema for coverage geometry and functions
ISO 19124 - Imagery and gridded data components
ISO 19125 - Simple feature access – Common architecture
ISO 19125 - Simple feature access - SQL option
ISO 19125 - Simple feature access – COM/OLE option
ISO 19126 - Profile - FACC Data Dictionary
ISO 19127 - Geodetic codes and parameters
ISO 19128 - Web Map Server Interface
ISO 19129 – Imagery, gridded data framework
ISO 19130 – Sensor and data models for imagery and gridded data
ISO 19131 - Data product specification
ISO 19132 - Location based services possible standards
ISO 19133 - Location based services tracking and navigation
ISO 19134 - Multimodal location based services for routing and navigation
ISO 19135 - Procedures for registration of geographic information items
ISO 19136 - Geographic information - Geography Mark-up Language (GML)
ISO 19137 - Geographic information - Generally used profiles of the spatial schema and of similar important other schemas

As soon as standards for different issues are established within the NGIS, they will be published and described here.