#!/usr/bin/env python
# coding: utf-8

# <img style="float: right;" src="./img/es2_logo_tiny.jpg"></img>

# # 03-WCS and QGIS

# <a href="./02-WCS_in_python.ipynb"><< 02-WCS and Python </a>&nbsp;<space>&nbsp;<space>&nbsp;<space>&nbsp;<space>&nbsp;<space>&nbsp;<space>&nbsp;<space>&nbsp;<space>&nbsp;<space>&nbsp;<space> <a href="./04-WCPS_intro.ipynb">04-Introduction to WCPS >></a>

# [QGIS](http://www.qgis.org/en/site/) is a poplular open-source desktop-based Geographical Information System that bases on the collaboration and development of people within the geospatial data community. Based on individual plugins, QGIS can be enriched with a wide range of additional functionalities.  
# 
# Per default, QGIS can be used as a WCS 1.1.1.1 compliant data server. ECMWF's WCS server is compliant to WCS 2.0 and gladly, there is a QGIS plugin that can be installed to be also compliant to WCS 2.0.
# Thapaliya & Misev (2014) built the [QgsWcpsClient1](https://plugins.qgis.org/plugins/QgsWcpsClient1/) plugin, which allows to connect to a OGC WC(P)S server and to execute a WCPS query for direct import to QGIS. Figure below shows an example of a WCPS query executed in QGIS to retrieve sea surface temperature data from ECMWF for 31 December 2001.

# <img src="img/qgis_workflow.png" width="800">
# <center><i>The QGIS desktop application and a simple three step approach to request data via a WCPS query: (1) install and load the [QgsWcpsClient1](https://plugins.qgis.org/plugins/QgsWcpsClient1/) plugin, (2) connect to a WCS server endpoint and (3) request data with a WCPS query.</i></center>

# A connection can be made either to ECMWF's service endpoint or to any other WCS 2.0 server. Further service endpoints are:  
# * Planetserver: http://access.planetserver.eu:8080/rasdaman/ows
# * EO Data Service: http://eodataservice.org/rasdaman/ows
# * Marine Data Service: http://earthserver.pml.ac.uk/rasdaman/ows
# 
# Once the connection is established, data on the server can be accessed via a WCPS query. Figure below shows (1) data from the Plymouth Marine Laboratory, the the marine science data provider of EarthServer-2 and (2) ERA-interim sea surface temperature from ECMWF.

# <img src="img/qgis_data.png" width="800">
# <center><i>Two examples of a coverage requested and retrieved via a WCPS query and visualized on-the-fly with QGIS: (1) from Plymouth Marine Laboratory's web service and (2) from ECMWF's webservice. (1) shows the ocean colour from ESA's Climate Change Initiative for 31 December 2001. (2) shows the ERA-interim sea surface temperature for 31 December 2010.</i></center>

#   

# WCPS queries can do complex calculations on-the-fly. Figure below shows two examples, how a false-colour composite of the planet MARS and a calculated NDVI from the Landsat8 satellite can be loaded on-the-fly into QGIS for further processing.

# <img src="img/qgis_data2.jpg" width="800">
# <center><i>Two examples of a coverage requested and retrieved via a WCPS query and visualized on-the-fly with QGIS: top: False color composition for a CRISM L observation image from Planetserver and bottom: an on-the-fly calculated NDVI from a Landsat 8 satellite image from the EO Data Service.

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