Experience from CNIG – IGN Spain - March 2017 (Updated on January 2018)

Description

Spanish experience from the Geographic Information National Centre (CNIG) in the implementation of INSPIRE Download Services using Web Coverage Services (WCS) for the Elevation theme.

• Reference documentation:
  • Technical Guidance for the implementation of INSPIRE Download Services using Web Coverage Services (WCS). Version 1.0
  • D2.8.II.1_v3.0 Data Specification on Elevation – Technical Guidelines
• Spatial data sets (to be provided as coverages):
  • Original data:
    • Digital Terrain Models (DTM) with different grid-cell size using EPSG:25830 (ETRS89-UTM30) for Peninsula and Balearic Islands, and EPSG:4083 (REGCAN95-UTM28) for Canary Islands.
    • Format: ASCII Grid files by units of 20' latitude per 10' longitude.
    • EVRS: transformation from the national height system has not been implemented yet.

    • Zone	RectifiedGridCoverage	grid cell size (m)
      Peninsula and Balearic Islands	Elevacion25830_1000	1000
      	Elevacion25830_500	500
      	Elevacion25830_200	200
      	Elevacion25830_25	25
      	Elevacion25830_5	5
      Canary Islands	Elevacion4083_1000	1000
      	Elevacion4083_500	500
      	Elevacion4083_200	200
      	Elevacion4083_25	25
      	Elevacion4083_5	5

       

  • Reprojected data to publish Spatial Data Sets using INSPIRE CRS (EPSG:4258)
    • Format of each coverage: JPEG 2000 files.
    • EVRS: transformation from the national height system has not been implemented yet.

    • Zone	RectifiedGridCoverage	grid cell size (m)
      Spain	Elevacion4258_1000	1000
      	Elevacion4258_500	500
      	Elevacion4258_200	200
      	Elevacion4258_25	25
      	Elevacion4258_5	5

       

• Publishing of the download service (WCS 2.0)
  • Mapserver 6.4.1 (problems with operation getCoverage in lasted version, 7.0.4)
  • A Mapserver configuration file (.map) was created with the following items:
    • Original coverage use tileindex for ASCII Grid files
    • Reprojected coverage use directly JPEG 2000 file (EPSG:4258)
  • An off-line static capabilities file served was created, which is served by Apache. The mandatory ExtendedCapabilities element was included in the capabilities file to allow publishing an INSPIRE compliant service, with the following content:
    • MetadataUrl: link to the corresponding metadata record within the Discovery Service (GetRecordById operation).
    • Supported Languages: Spanish (spa).
    • SpatialDataSetIdentifier: RS_Identifier (code + namespace) used for each coverage.
  • Delivering coverage data using multipart representation:
    • MEDIATYPE Mapserver parameter is included within the GetCoverage requests (FORMAT=image/tiff&MEDIATYPE=multipart/related)​
    • The format encoding has two parts:
  1. GML document representing all coverage components except the range set.
  2. GeoTIFF file with the range set.

Data themes covered:

Elevation (Rectified Grid Coverage).

Software used:

Mapserver 6.4.1, Notepad++, Apache, CentOS Linux.

Status:

Ongoing.

Service URL Endpoint:

http://servicios.idee.es/wcs-inspire/mdt?REQUEST=GetCapabilities&SERVICE=WCS&VERSION=2.0.1