OGC Testbed-12 Kick-Off – Contributions – LSA Thread

OGC Testbed-12 Kick-Off

USGS - Reston, VA - 2016-03-03

Stephan Meißl stephan.meissl@eox.at @Schpidi

Andrea Aime andrea.aime@geo-solutions.it @geowolf

 This work is licensed under a Creative Commons Attribution 4.0 International License.

Thanks for your attention

Contributions

LSA Thread

• 19 Coverages
  • NA001 WCS new profile 1
  • NA006 WMTS for time-varying layers
  • NA007 WMS for NetCDF
• 16 Big Data Tiles
  • A017 Big Data Tile Database Implementation
  • A076 Contributions to Big Data Database ER

Parallel activity EVO-ODAS

• Coordinated by DLR - German Aerospace Center
• ESA funded project
• Objective to improve the acceptance of online EO data access services and standards and to promote their evolution and diffusion
• Overlapping with Testbed-12 e.g. multidimensional data, security, etc.
• wiki.services.eoportal.org/tiki-index.php?page=EVO-ODAS

NA001 WCS new profile 1

• Extend EO-WCS support for 3D space and 1D time data in EOxServer

EOxServer in brief

• MIT-style license
• Closely following the concepts of WCS & EO-WCS
• Implementing WCS, EO-WCS, WMS, EO-WMS, WCS-T, WPS, OpenSearch, etc.
• Based on Open Source stack including Python, Django, MapServer, GDAL, etc.
• Included on OSGeo Live
• eoxserver.org
• github.com/EOxServer/eoxserver

NA006 WMTS for time-varying layers

• Extend temporal WMTS tile assembly in MapCache - EOX
• Implement logic to avoid requesting empty tiles in MapCache - EOX
• Participate in OGC WMS.SWG - EOX
• Support for communication of empty areas in GeoServer WMS/WMTS - GeoSolutions
• Improved Support for TIME and other dimensions in GeoServer WMS/WMTS - GeoSolutions

MapCache in brief

• Suite
• MIT-style license
• Stable release 1.4
• Tiling Library with Apache, FastCGI, Nginx, and Node frontends
• Native code: Fast and Efficient
• mapserver.org/mapcache/index.html
• github.com/mapserver/mapcache

MapCache main features

• Multiple Protocols like WMTS, WMS, TMS, etc.
• Multiple cache backends e.g. SQLite, disk, (Geo)TIFF, REST
• Tile Management Features: seeding, recompression, interpolation
• (OGC) Proxy: serve from cache if possible, forward otherwise
• Mixed jpeg + png format
• Reconstruct paletted 1bit PNG from uniform color
• and many more

Time dimension

• Each timestamp corresponds to a limited extent
• Dynamic Mosaic given a requested time interval
• Create Animated GIF from selected tiles

GeoServer in brief

• WMS/WFS/WCS/WPS/CSW implementation
• GUI based configuration/REST service based configuration
• Dimension support in WMS, WMTS, and WCS/EO-WCS (with custom extensions)
• NetCDF-CF support as input for most services
• NetCDF-CF output in WCS 2.0 only
• Pluggable Authentication - basic/digest/cas/j2ee/proxy
• Pluggable Authorization - authorize by area, attribute, whatever filter
• WPS process for asynch extraction of large data extractions
• GeoPackage generation (tiles and vector)

GeoWebCache/GeoServer WMTS dimension support

• Configure GWC to accept "TIME", "ELEVATION" and "DIM_REFENCE_TIME" as valid request params
• Builds a separate tile cache for each combination of values
• Use "disk quota" to avoid disk space usage explosion
• In memory clustered cache for data with very frequent updates

Drill down and discover multiple dimension relationships

• Domains of the dimensions related with each other (e.g., reference_time and time)
• Need a way to find out from the client which values are available by drilling down from one dimension to the other
• Commonly done by exposing the ND mosaic index as a WFS layer, spatial, attribute filtering, paging and sorting available but...
• No direct way to correlate the dimensions exposed in WMS with the index exposed in WFS, we need to amend that
• Also, find more compact ways to list the available values e.g. select distict(dim_att) where dim_att between x and y and ...

Avoid requesting empty tiles - idea 1

• Have a separate binary grid reporting availability
• One tile to report the availability of 256x256 "data" tiles
• Served as a separate WMTS layer with no/custom CRS, and linked to the data layer somehow?

Avoid requesting empty tiles - idea 2

• Return a custom HTTP header indicating an empty tile
• Tiles on lower zoom levels don't need to be requested

NA007

• Add support for WMS extensions of ncWMS in EOxServer e.g. color scales in GetMap requests or GetTimeseries request type - EOX
• Add support to filter WMS Capabilities e.g. XPath in EOxServer - EOX
• Add support for further WMS extensions of ncWMS in EOxServer - EOX
• Enhance NetCDF-CF metadata handling in EOxServer - EOX
• Dynamic ColorMaps Support in GeoServer WMS - GeoSolutions
• Improved GetLegendGraphic in GeoServer WMS - GeoSolutions
• Simplified Harvesting of NetCDF-CF files in GeoServer - GeoSolutions
• Improved GetCapabilities for large number of datasets (possibly using XPath) in GeoServer - GeoSolutions

WMS in EOxServer

• Based on
• Full support of EO-WMS including time dimension, outlines, bands, etc.
• Masking & mosaicing

Dynamic colormaps support in GeoServer

• Collect statistisc from data (e.g. histogram)
• Create a color map on the fly based on the statistics and a named color map type
• Based on GeoServer own SLD extension called "Rendering transformations" (aka "apply me a WPS process on the fly before rendering data")

GetLegendGraphics for dynamic colormaps

• GetLegendGraphics needs to learn about dynamic colormap
• Display the right colormap, display the right values on the side

Easier setup of NetCDF mosaics in GeoServer

• Now requires setting up a XML mapping file describing the structure of the file
• Automatically setup the data leveraging the CF conventions instead

Improve working against large capabilities documents

• Search in very large capabilities documents, lots of layer (XPath?)
• Move out long dimension listings to a separate set of pageable, searchable calls

LSA - Big Data Tiles

• Contributions to & review of Big Data Database ER
• Big Data Tile Database Implementation
  • Evaluate PostgreSQL as alternative to SQLite in GeoPackage
  • Implement database generation, dump, and restore scripts for PostgreSQL as alternative to SQLite in GeoPackage