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2Challenge the future
Overview
• Land Use in INSPIRE• Introduction to coverages• Land use modeling• Land use coverages
3Challenge the future
INSPIRE: Land Use
My task:Make an information model for Land Use according to INSPIRE rules
Definition of Land Use:Territory characterised according to its current and future planned functional dimension or socio–economic purpose (e.g. residential, industrial, commercial, agricultural, forestry, recreational).
Ground rule of land use experts:Each piece of land has exactly one land use category! No gaps (category UNUSED) no overlap (category MULTIPLE LAND USE) Land Use is a Coverage!
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Coverages
• feature that acts as a function to return values from its range for any direct position within its spatial, temporal or spatiotemporal domain
In modeling a coverage is defined by defining a type for its domain and range
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Main characteristic of Coverage
Continuous
(useful interpolation in range values)
Discrete
(interpolation on range is useless)
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Coverage implementation
Different implementations•Raster/Grid •Topological Structure•TIN•Collection:
• Points• Lines + interpolation method• Polygons
Choice depends on:•The way the data is acquired•The way the data is used•Storage considerations
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Raster Coverage
• Continuous
• Discrete
Efficient encoding in files:-Implicit domain geometry-Range values can be compressed
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Categorizing land use Coverages
• Coverages are always discrete (no interpolation)• Land use is a discrete coverage in all member states
implemented as:• Raster coverage• Polygon coverage• Point coverage (LUCAS)
copyright Eurostat 2011
LUCAS: Land cover dataset for Europe
1 100 000 points
LAND COVER classes1 ARABLE LAND2 PERMANENT CROPS 3 GRASSLAND4 WOODED AREAS AND SHRUBLAND5 BARE LAND, RARE VEGET.6 ARTIFICIAL LAND7 WATER
First phase sample for stratification: orthophoto interpretation
2km squared grid
Ground survey
Parameters•Land cover•Land use•pictures•etc.
Sample of around 260,000 pts
Second phase sample: in-situ data collection
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Land Use Range
• The classification value is a complex object Land Use is always a discrete coverage
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What does INSPIRE offer
• In the Proposed Changes to the Generic Conceptual Model and Encoding Guidelines one chapter about coverages
• Based on ISO 19123 Coverages and ISO 19136• Two coverage hierarchies:
1. Coverage-As-Polygon-Value-Pair2. Coverage-By-Domain-And-Range
«featureType»Coverages (Base)::Coverage
«featureType»Coverages (Domain and Range)::
CoverageByDomainAndRange
«featureType»Coverages (Geometry-Value Pairs)::
DiscreteCoverageGeometryValuePairs
«type»Coverage Core::CV_Coverage
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Discrete Coverage Geometry Value Pairs Model
Discrete point coverage
Discrete polygon coverage
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Coverage by Domain and Range
Discrete point
coverage
Discrete surface
coverage
Discrete grid
coverage
This shared superclass I chose as base class for Land Use
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Now the encoding part.
• The UML diagram model is automatically translated to a GML application schema.
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Implementation of Coverage by Domain and Range
Four options for Range:•ValueArray
homogeneous arrays of primitive and aggregate values.
•AbstractScalarValueListList of scalar values
•DataBlockTuples of values are stored as a long list of Comma Separate Values.
•FileActual data is stored in a file outside GML
Not what I want
Not what I want
What I want but not the way I want it.
Might be right for gridded data.
So I went for a Coverage by Geometry Value Pairs
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Implementation of Coverage by Geometry-Value-Pairs
It works but….
Hi Wilko,
I had a quick look and there are quite a number of issues in the XML so I would suggest not to present it as a sample template.
I am also convinced that the coverage representation is not the right way, but that is a separate issue.
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Conclusions / Limitations
• INSPIRE coverage model is unclear: Why do we have two types of coverages in the top of the hierarchy?
• INSPIRE coverage implementation wrong: Why do I have to provode a domain and range if I want to encode a Coverage-by-geometry-value-pair?
• Now I have GML but how to serve it Efficiently (WCS???)
Time for a major revision of coverages in: INSPIRE, OGC and ISO/TC 211