Open Source Visualisation with ADAGUC Web Map Services

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1 Open Source Visualisation with ADAGUC Web Map Services Maarten Plieger Ernst de Vreede John van de Vegte, Wim Som de Cerff, Raymond Sluiter, Ian van der Neut, Jan Willem Noteboom 1

2 ADAGUC project Cooperative project finished end of 2009 Dissemination of atmospheric data to GIS community OGC webservices (WMS,WCS) for data in NetCDF4/HDF5 files Web portal: Layers from several services Download data through WCS interface WMS/WCS service component ADAGUC Product Standard for metadata; storage in NetCDF4/CF 2 Demo site: A good start! Atmospheric Data Access for the Geospatial User Community

data through WCS interface WMS/WCS service component ADAGUC Product Standard for metadata; storage in

3 ADAGUC server and viewer software Geographical information system to visualize netcdf files via the web Web Map Service and Web Coverage Service Developed at KNMI (2009 till present) Server: C++ application Viewer/Client: JavaScript application NetCDF4, HDF5 and OpenDAP Multi dimensional data supported! Can serve true color data (1 byte per channel, RGBA) Very fast nearest neighbour reprojection (C++) Both open source since 2013! Atmospheric Data Access for the Geospatial User Community 3

and OpenDAP Multi dimensional data supported!

4 Web Map Services: From data to images + NetCDF Data (big, 5.5Gb) PNG images (small, 180Kb) Combined geographically 4 Data from MSGCPP:

5 Introduction to OGC services OGC Open Geospatial Consortium currently ~450 organizations standards for geospatial content and services GIS data sharing and processing Services used within the ADAGUC project: ADAGUC: Atmospheric Data Access for the Geospatial User Community, finished in 2009) Web Map Service (WMS) - for images Web Feature Service (WFS) - for vector data (features) Web Coverage Service (WCS) - for raster data (coverages) WMS is primarily for visualization WFS and WCS are for retrieval of data 5

Geospatial User Community, finished in 2009) Web Map Service (WMS) - for images Web Feature Service (WFS) - for vector data

Standard is developed and maintained by the Open Geospatial Consortium Generated images are geo-referenced Images from several sources

6 Web Map Service for visualizations Generates visualizations of geospatial data in the form of 2D images, suitable for transfer over the internet (JPG/PNG/GIF) REST based: Compose an URL with key value pairs, and you will get an image! Standard is developed and maintained by the Open Geospatial Consortium Generated images are geo-referenced Images from several sources can be easily combined Images have dimensions Time, elevation, member WMS services can be viewed in many web based clients OpenLayers, Leaflet, GoogleMaps, ADAGUC viewer, 6

7 WMS Requests - overview GetCapabilities GetMap GetLegendGraphic GetFeatureInfo 7

8 ADAGUC WMS Client: KNMI WMS viewer WMS GetMap WMS GetCapabilities WMS GetLegendGraphic WMS GetFeatureInfo 8 Data from Globemission: NOx emissions from GOME-2

9 Web Coverage Service WCS (similar to WMS) Similar to WMS, but returns data instead of images Returns observations in a regular spaced grid in many projections Generates data in geotiff, ascii, netcdf 3/4, HDF5, etc Web Map Service: images Web Coverage Service: data 9

spaced grid in many projections Generates data in geotiff, ascii,

10 ADAGUC Viewer WCS Client 10

11 Atmospheric data what s so special? Observations in space and time Point data for example observing stations Gridded data for example satellite or precipitation radar Model data: forecasts in time and space, usually starting from a certain reference time Usually gridded data ( fields ) Multidimensional data: Atmosphere is a 3D structure Time makes 4D Reference time makes 5D Ensembles make 6D 11

satellite or precipitation radar Model data: forecasts in time and space, usually starting from a

Used data format: NetCDF4-CF NetCDF4 with Climate and Forecast conventions (CF conventions) Standard names, standard units (http://cf-pcmdi.llnl.

12 Used data format: NetCDF4-CF NetCDF4 with Climate and Forecast conventions (CF conventions) Standard names, standard units ( Identify and compare data Locate data in space time as a function of other independent coordinate variables (time, latitude and longitude): OGC 12

gov/documents/cf-standard-names/) Identify and compare data Locate data in space

13 Regular grids 13

14 Projected grids 14

15 Curvilinear grids 15

16 Point data 16

17 UGRID Polygons 17

18 True color RGBA images in NetCDF using uint type 18

19 OPeNDAP for data access and subsetting OPeNDAP is the name of the organization and the name of the protocol Open-source Project for a Network Data Access Protocol Data is stored at remote server Data model is similar to NetCDF s data model (with differences) N-dimensional array container, with variables, dimensions and attributes Only requested pieces of data are sent Accessing small pieces of large files on a remote server can still be quick Data is requested based on sub-setting along dimensions OPeNDAP resources can be opened locally on your computer as if it were local files using the NetCDF library Local files versus remote files is transparent The concept of a file is gone, an OPeNDAP endpoint can represent thousands of files aggregated along a dimension E.g. Usually concatenate a large time series observation to one endpoint using the time dimension 19

large files on a remote server can still be quick Data is requested based on sub-setting along dimensions OPeNDAP resources can be opened locally on your computer as if it were local files using the

20 Data standards Work done on client Array based data Referenced data WCS Graphics WMS Data files HTTP / FTP Work done on server (de Boer & Plieger, 2014) 20

HTTP / FTP 01001010010 01010010010 10010100100

21 Coordinate systems and reprojection of data OGC 21

22 Projection, resizing & subsetting Meteosat HRVIS: Satellite view projection Resolution: 3520 x 4660 Radar precipitation: Polar stereographic projection Resolution: 700 x

23 Combined in Dutch Rijksdriehoekstelsel projection Dutch Rijksdriehoekstelsel Resolution: 1000 x Rendering time ~500ms

24 Questions? 24 Thanks all for watching!

OGC at KNMI: Current use and plans Available products

OGC at KNMI: Current use and plans Available products Maarten Plieger KNMI R&D Ernst de Vreede, John van de Vegte, Wim Som de Cerff, Ian van der Neut, Raymond Sluiter, Jan Willem Noteboom Contents 1. ADAGUC