Global Positioning System Reference
In-Depth Information
Order-related query transformations can be considered in its context. No
operational implementation is known, though.
SciQL is an array extension to the SQL: 2003 based query language of the
MonetDB column store DBMS. It integrates the semantics of set, sequence,
and array. With minimal modifi cations to the SQL syntax, it allows for
expressing array operations within the common language framework. The
drawback for scientists is that it is mainly targeted for experienced SQL
programmers. Also, SciQL still lacks an array storage manager—currently,
arrays are emulated by relations, which leads to ineffi ciencies.
The shared-nothing parallel database system SciDB was designed for
dense array processing. It handles multi-dimensional, nested arrays within
array cells. SciDB is novel in that it has no built-in operators, but operators
which are all user-defi ned functions. SciDB is supposed to be more than
an Array DBMS, a complete system for managing and analyzing scientifi c
data. Therefore, it is supposed to include a complex versioning system,
in situ
data processing, array and cell provenance, and support for uncertain
cell values (Rusu and Cheng 2013).
EXTASCID (Cheng and Rusu 2012) is a parallel system for handling
efficient analysis of large-scale scientific data. It manages massive
heterogeneous data by partitioning data, executing at parallel, and having
a relational and array data model. EXTASCID is architecture independent
employing multi-threading and shared-nothing parallelism.
A special case in the table is OPeNDAP—it is not a database system
but offers dedicated array access and processing functionality. Other
non-database solutions for manipulating raster data are offered within
MATLAB,
10
the programming language R,
11
Orfeo toolbox,
12
etc.
The fi rst Array DBMS based on a rigid formalization and comprising a
fully fl edged query language (Baumann 1994; 1999) backed by the highly
effective optimizations (Baumann et al. 2009) is rasdaman, short for “raster
data manager”.
13
It will be detailed further down below, as it is the Reference
Implementation
14
for the OGC WCS 2.0 geoservice standards suite.
Array Models
In this section, array data models, which have undergone a rigid
formalization, are informally presented. Important candidates are
Array
Algebra
,
AML
,
AQL,
and
RAM
. Although recently more relevant models
10
http://www.mathworks.com/products/matlab/, “last seen on 31 March 2013”
11
http://www.r-project.org/, “last seen on 31 March 2013”
12
http://www.orfeo-toolbox.org/otb/, “last seen on 31 March 2013”
13
http://www.rasdaman.org, “last seen on 31 March 2013”
14
http://www.esri.com/software/arcgis/arcsde, “last seen on 31 March 2013”
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