Custom Query (2765 matches)

The WMS service in rasdaman could allow the publication of 2D slices of coverages as WMS layers. More generally, it could allow any RasQL operation that outputs a 2D array to be applied a priori to a coverage before it is published as WMS layer.

The enhancement request is rooted in ​rasdaman-users::"visualization of sliced 3D coverage using WMS", specifically for enabling the publication of a 2D map inside a 3D cube spatiotemporal collection of maps.

Amongst the ideas that arose in the discussion, one possible way to implement such enhancement could be:

• add a further field in petascopedb::ps_layers to store an optional replacement for the layer label in the RasQL request yielded by Petascope WMS (see Java method petascope.wms.RequestConverter.buildFullImgExp(...)), e.g. rasql_coll:

  petascopedb=# SELECT ps_layers.name, ps_styles.rasqlop, ps_layers.rasql_coll 
  petascopedb-# FROM ps_layers, ps_styles 
  petascopedb-# WHERE ps_styles.layerid=ps_layers.layerid;
      name   |         rasqlop          |    rasql_coll
  -----------+--------------------------+------------------
    standard |  standard * {1c, 1c, 1c} |  img[6,*:*,*:*]
  (1 row)
  

• If ps_layers.rasql_coll <> NULL then Petascope would replace all the labels of the collection in the RasQL query with the rasql_coll string, so that for instance:

  scale(
    extend( img0[0:630,700:1120],[0:630,700:1331] ),
    [0:255,0:255]
  )
  

  would turn to:

  scale(
    extend( (img[6,*:*,*:*])[0:630,700:1120], [0:630,700:1331] ),
    [0:255,0:255]
  )
  

• last and not least, the WMS import utilities [WmsImportTools] in <rasdaman>/applications/rasgeo/wms-import/utilities/ would need to allow the configuration of such new field in the database, as well as to properly select the data in rasdaman for the definition of the WMS metadata (bbox, etc.) and the creation of the pyramid collections.

Only integer/floats are supported by GML, so having a time axis can not be encoded in the coverage output, or it can be encoded by breaking the XML schema validation.

with a wcs2.0 getCoverage request, when something went wrong, petascope return a malformed http response Firefox and chrome are anyway able to open the xml file, python and wget not!

Example: subset out of coverage bounds

• with firefox i obtain the attached xml file.

• with wget i obtain the following error:

—2013-03-20 17:57:40— ​http://earthserverclimate-dar:8080/petascope/wcs2?service=WCS&Request=GetCoverage&version=2.0.0&subsetX=x(40.961914,40.961914)&subsetY=y(55.172852,55.172852)&subsetT=t,CRS:1(149020,150559)&CoverageId=MOD_LST_4326_001 Resolving earthserverclimate-dar (earthserverclimate-dar)… 192.168.0.151 Connecting to earthserverclimate-dar (earthserverclimate-dar)|192.168.0.151|:8080… connected. HTTP request sent, awaiting response… -1 2013-03-20 17:57:40 ERROR -1: Malformed status line. Retrying.

• with python the error is:

Traceback (most recent call last):

File "/opt/mea/LIB-Library/WCS_utility.py", line 492, in execute

r = conn.getresponse()

File "/usr/lib/python2.7/httplib.py", line 1034, in getresponse

response.begin()

File "/usr/lib/python2.7/httplib.py", line 407, in begin

version, status, reason = self._read_status()

File "/usr/lib/python2.7/httplib.py", line 395, in _read_status

raise BadStatusLine(line)

BadStatusLine: HTTP/1.1 0

How to reproduce the issue: request subset out of coverage bounds with wget utility

wget ​http://host:8080/petascope/petascope/wcs2?service=WCS&Request=GetCoverage&version=2.0.0&subsetX……………

The issue has been introduced recently, old petascope works

Tested with rasdaman-petascope-8.4.0-rc.2.2.el6.noarch

Ciao Damiano