ISO/INSPIRE Metadata Support: Difference between revisions
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* tag - just copy of string from first braces | * tag - just copy of string from first braces | ||
* object – for reading and holding metadata in python objects is used OWSLib library. | * object – for reading and holding metadata in python objects is used OWSLib library. | ||
Most of object are initialized by configuration file wx.metadata/config/init_md.txt. Some metadata attributes are necessary initialized directly in this(object) parameter. Best example is the metadata contact object(organization,email) which can be initialized for many times. | |||
example: responsible party | example: responsible party | ||
Revision as of 14:54, 15 August 2014
ISO 19115:2003- Geographic information -- Metadata
ISO 19115:2003(ISO) defines the scheme required for description of geographic information and services. It provides information about the identification, the extent, the quality, the spatial and temporal scheme, spatial reference, and distribution of digital geographic data.more
About wx.metadata
New metadata management is currently available in GRASS add-ons. Package for creating and editing metadata according to EN ISO 19115, described here, consists of tree modules. Modules r.info.iso and v.info.iso are command line based and support conversion from current native metadata management (r.info, v.info) into ISO based metadata. GUI based module - g.gui.metadata offers advanced tools for management of metadata.
Dependencies and installation
Dependencies
Current development of metadata management has dependence on external libraries:
- OWSLib development version ()
git clone git://github.com/geopython/OWSLib.git cd OWSLib && sudo python setup.py install
- Jinja templates
git clone git://github.com/mitsuhiko/jinja2.git cd jinja2 && sudo python setup.py install
Installation of metadata management
Currently the wx.metadata package is available in GRASS Add-ons.
GRASS> g.extension wx.metadata
Modules and usage
Naming of metadata files and storage
The metadata product fully supports XML Default location of exported metadata uses folder “metadata” in GRASS Location. In case the metadata file name is not changed, the name is build from prefix according to characteristic of maps. For raster maps prefix is derived from current nomenclature - 'cell' and for vector map – 'vector' by the same way. File name is derived from the the name of the map. Postfix-extension is '.xml'.
example: vector map - roads vector_roads.xml
Metadata profile
The metadata profile defines attributes, which can be edited in this editor. The editor offers the already mentioned two profiles(Basic and Inspire). Editor also support loading of customized profiles. See Creation of custom ISO based profile.
Modules r.info.iso and v.info.iso
Command line based modules implements conversion of native GRASS metadata to ISO based XML metadata files. Identical configuration applies for both modules. Products of these modules differ partly in certain metadata attributes related to differences between raster (r.info) and vector (v.info) maps metadata.
- Currently are available two build-in ISO profile:
The Basic profile is substituted from intersection between GRASS native metadata and INSPIRE profile. The intersect (subset) includes all available GRASS metadata. Metadata which cannot be assigned to ISO based attributes are stored in metadata attribute - abstract. The Inspire profile fulfills the criteria of INSPIRE profile. Values which are not able to get from native GRASS metadata are filled by text string '$NULL'. This rule applies for both profiles.
Parameters of modules:
- map - selection of map for metadata creation
- profile - selection of metadata profile (basic or inspire)
- output - path to output XML metadata file. Default = according to naming&storage rules
Module g.gui.metadata
Metadata editor (editor) includes graphical interface for conversion metadata from r.info and v.info to ISO based metadata, editing metadata files and creating metadata templates. In addition, the graphical module allows validating of INSPIRE and Basic profile.
Creation of metadata
Editor offers two editing modes. The first one allows to create metadata from selected GRASS maps from an active location. The second one allows editing of external metadata file.
GRASS metadata map editor
Combo box for selection of ISO profile:
- basic
- inspire
- load custom – this option allows to load metadata profile from file. For example in case of use of predefined template. With this selection the editor make intersection of GRASS Basic profile(all available metadata for selected map) and loaded custom profile.
External metadata editor
In this case to load metadata profile file and metadata file is necessary for editing. This option does not support any connection with GRASS maps metadata. Of course, it is possible to load exported metadata from the past.
Defining templates
This function allows to create pattern of metadata profile. In other words it support defining fixed values to template. With using created templates, the editor does not initialize texts inputs of defined values. These attributes is able to see only in Tree Browser. Direct link on this function is multiple editing mode (see below).
Usage
- If check-box of metadata attribute is checked, the OWSLib object in template will be replaced by value. Unchecked attributes will not change this 'part' of the template.
example: Result of checked attribute
<gmd:dateStamp>
<gco:Date>2013-01-01</gco:Date>
</gmd:dateStamp>
example: Result of unchecked attribute
<gmd:dateStamp>
<gco:Date>{{ md.datestamp }}{# tag="md.datestamp" , name="Metadata date" ,\
ref= "Part B 10.2" , desc= "Date that the metadata was created.",type = "date" ,
example = "2005-03-27" , multi= 0 , group= "Metadata" , multiline= False #}</gco:Date>
</gmd:dateStamp>
- The yellow background of text fields indicates metadata attributes, which are not possible parsed from GRASS map information.
Editing metadata of multiple map selection
Advantages of this editing mode is in work using of defined template. This option can be used by selection of multiple maps in data catalog.
Validation of metadata profile
On the right side of editor there is a validator of metadata. Currently, validator is able to validate two build-in profiles. For selection of profile “Load custom” is set by default in the inspire profile.
Updating GRASS native metadata
The g.gui.metadata module allows to update native GRASS metadata with using modules r.support and v.support. The intersection between ISO based metadata and r|v.support is limited by available parameters for these modules.
for vector maps(v.support):
- organization =
Creation of custom ISO based profile
Creation of own custom ISO based profile is with using Jinja template syntax and some addition rules. The main item of template is composite from two braces. Both of them are fully according to syntax of Jinja template. First holds information about statements of loop or condition and also simple Python object. Second braces according to Jinja template syntax is represented by comment {# #}. In this braces additional information for generating graphical interface of editor are stored. In addition also information about individual metadata attributes (name, example, description, multiplicity, etc) is included.
The first braces
Contain object of OWSLib which holds the metadata value. This values can be object which is describing single variable or list of variables. Value of some attribute can be defined many times(according to ISO). This attributes must be defined in block of template with starting statements and ending mark of block. Only allowed loop statement is FOR(see jinja2 manual). The XML based text of block will by duplicated according to number of items in the list.
Initialize of OWSLib objects
Most object are initialized in configuration of file which is stored in wx.metadat/config/init_md.txt example: Default configuration file for the build-in Basic and Inspire profile:
self.md.identification = MD_DataIdentification() self.md.dataquality = DQ_DataQuality() self.md.distribution = MD_Distribution() self.md.identification.extent = EX_Extent() self.md.identification.extent.boundingBox = EX_GeographicBoundingBox()
- on the left side of equation is obligatory prefix 'self.md'. Postfix(name of variable) is open. On right side is OWSLib object
Single element
In case if the value of metadata element is declared only once: example: Identifier
{{ md.identifier }}
example: Lineage
{{ md.dataquality.lineage }}
Loop or Condition statements
Loops and condition are defined in by starting braces and ending braces '{% -%}' . Start of block:
example: for statement
{% for co in md.contact -%}
Editor allows to use Python 'zip' function and 'len' function. Note- in Jinja syntax is Python len(length) function defined specifically.
example: zip
{% for (u,d) in zip(md.identification.uom,md.identification.distance) -%}
example: len
{% if md.identification.denominators|length > 0 -%}
End of block is defined by:
example: if statement
{% endif -%}
example: for statement
{% endfor -%}
The second braces
The second braces(by Jinja syntax comment) contains these parameters:
- tag - just copy of string from first braces
- object – for reading and holding metadata in python objects is used OWSLib library.
Most of object are initialized by configuration file wx.metadata/config/init_md.txt. Some metadata attributes are necessary initialized directly in this(object) parameter. Best example is the metadata contact object(organization,email) which can be initialized for many times.
example: responsible party
{% for co in md.contact -%}{# object="CI_ResponsibleParty()" #}
{{ co.organization }}{# object="CI_ResponsibleParty()" #}
{{ co.email }}{# object="CI_ResponsibleParty()" #}
{{ co.role }}{# object="CI_ResponsibleParty()" #}
{% endfor -%}
- name – free text string describing the name of metadata item
- ref – free additional information. By default should be reference of ISO attributes
- type – data type characteristic. Input text field validator for 'email' and 'date' is implemented.
- desc – free text which should describe or define the characteristic of metadata item
- example – free text with example of the value for metadata item
- group- label of the notebook list(tab) in editor.
- inbox- label of the box which includes attributes from the block of Jinja template. All items from one block of Jinja template must be in same box(same name).
- multi- 0 or 1. In case 0, the item cannot be duplicated= text field widget does not contain button for duplicating itself. Note that only OWSLib list based variables can be used with duplication button.
- inboxmulti- 0 or 1. In case 0, the items in box cannot be duplicated = box with items not dispose with button for cloning self.
- multiline – True = initialize text field with multilines editing. Suitable for longer texts input
example of second braces:
{# tag="md.dataquality.lineage" , name="Lineage" , ref= "Part B 6.1" ,/
desc= "General explanation of the data producers knowledge about the lineage of a dataset."/
,example = "Product 1 scenes correspond to the path/row of the Landsat orbit.." ,/
type ="string" , group= "Quality and Validity" , multiline= True #}
Syntax of Jinja template system and editor custom parser
- both of braces of one metadata element must be on same line
- after '{# ','{%' must be white space. Also before '#}' '-%}'