Παράρτημα 7Β
Τεχνική Τεκμηρίωση προτύπου
Urban Vector Map (UVMap)
Introduction
•
VPF data model
•
Basic concepts
•
Structure and Implementation
•
The vector product format (VPF) is a standard format,
structure, and organization for large geographic
databases.
•
VPF is based on a Georelational Data Model.
•
In this model, geographic information is represented
by using a combination of vector geometry, planar
topology, and relational database tables.
•
Features
•
Attributes
•
Primitives
•
Feature Classes
•
Metadata
•
Topology
•
A feature is a model of a real world geographic entity.
•
Features can be zero-, one-, or two-dimensional.
•
Features are logically composed of attributes and
primitives
•
Features are represented within the VPF data model
by feature classes
VPF Data Model
Basic VPF Concepts
Features
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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Attributes
•
Attributes provide information about the property of
an entity (feature).
•
Attributes are contained within VPF feature tables.
•
Primitives provide information about the location of
an entity (feature).
•
All features must be composed of at least one
primitive.
•
There are two basic types of primitives:
Primitives
••
••
•
Geometric primitives
Cartographic primitive
Geometric primitives are further broken down into
four categories:
••
••
••
••
Entity nodes
Connected nodes
Edges
Faces
Feature Classes
•
“Feature classes” are the fundamental concept by
which all features are modeled within VPF.
•
A feature class is logically composed of attribute data
and primitive data.
•
A feature class is physically composed of a feature
table and a primitive table.
•
Feature table
•
Primitive table
•
Primitive-to-feature relationships
•
Feature class relationships
Feature class components
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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Feature tables
COLUMNS
ID F_CODE ATR1
ATR2
ATRn TILE_ID* <PRIM>_ID*
1
ROWS
2
3
4
*Mandatory if tiled
Related Attribute Tables
•
Attribute data may also be stored in tables separate
from the feature table
•
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
These tables are called “Related Attribute Tables” or
RATs
27
Related attribute tables
TEXT FEATURE TABLE CONTAINING SYMBOLOGY
INFORMATION
ID
FCODE TILE_ID TXT_ID
STYLE
COLOR
1ZD040
Kern
Black
2
ZD040
Kern
Blue
3
ZD050
Kern
Black
4
ZD050
Kern
Blue
5
ZD050
Proportional
Magenta
FEATURE TABLE WITHOUT
SYMBOLOGY INFORMATION
RELATED ATTRIBUTE TABLE
CONTAINING SYBOLOGY
INFORMATIO
ID
STYLE
COLOR
ID
FCODE SYMBOL_ID TILE_ID TXT_ID
1
ZDO40
1
1
1
1
2
ZD040
2
2
1
2
3
ZD050
1
3
2
3
4
ZD050
2
Primitive tables
ID
<COORDINAT ES>
<T OPOLOGY>
1
2
3
4
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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Primitive types
•
There are four basic types of geometric primitives in
VPF:
—
—
—
—
•
END
CND
EDG
FAC
There is one cartographic primitive:
—
•
Entity node
Connected node
Edge
Face
Text
TXT
There are several types of supporting primitive tables:
—
—
—
Edge bounding rectangle
Face bounding rectangle
Ring table
EBR
FBR
RNG
Primitive type comparison
VPF
ARC/INFO
Entity node
Connected node
Edge
Face
Text
Point
Node
Arc
Polygon
Annotation
Table relations in VMAP model
FEAT URE T ABLE
ID
F_CODE
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
AT R1
PRIMIT IVE T ABLE
AT Rn
ID
COORDINAT ES
29
Feature Class types
•
There are two basic types of feature classes in VPF:
••
Simple
—
Point
—
Line
—
Area
—
Text
••
Complex
—
Multiple simple feature classes
Feature class types (cont’d)
Entity Node
Primitive Table
+
Point Feature Table
=
Entity Node
Point Feature Class
Connected Node
Primitive Table
+
Node Feature Table
=
Entity Node
Point Feature Class
Edge
Primitive Table
+
Line Feature Table
=
Line Feature Class
Face
Primitive Table
+
Area Feature Table
=
Area Feature Class
Text
Primitive Table
+
Text Feature Table
=
Text Feature Class
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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Feature Class relationships
Single
Coincide nt
One-to-one
One-to-many
Compound
Many-to-one
Compound-coincide nt
Many-to-many
Defining Feature Class relationships
•
VPF uses a several pre-defined tables in order to
specify the relationships and characteristics of
feature classes
••
Feature class schema (fcs) table
••
Feature class attribute (fca) table
Metadata
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
•
The VPF data model contains descriptive information
called “metadata”.
•
Metadata allows a VPF database to be “self-defining”.
•
Metadata is used to :
31
••
••
Describe the contents of a table
Provide information about other tables or files in
the database
Types of metadata used in VPF
•
Column definitions
•
Value description tables (vdt)
•
Narrative tables (*.doc)
•
Database header tables (dht)
•
Library header tables (lht)
•
Library attribute tables (lat)
•
Coverage attribute tables (cat)
•
Feature class attribute tables (fca)
•
Geographic reference tables (grt)
•
Data quality tables (dqt) and coverages (dq)
•
Reference coverages (tileref, libref)
•
The VPF data model recognizes four levels of
topology:
VPF Topology
••
••
••
••
•
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
Level 0
Level 1
Level 2
Level 3
Boundary representation (“spaghetti”)
Non-planar graph
Planar graph
Full topology
Topology is implemented in VPF through the use of
reference pointers.
••
Faces
••
Edges
••
Nodes
32
Topology implementation – Faces
Topology implementation – Edges
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
•
Winged-edge topology
•
Forward edges
33
Topology implementation – Nodes
•
Additional topological information is contained in the
node primitives.
•
Two types of node primitives are implemented in VPF:
••
••
Connected nodes
Entity nodes
VPF Structure and Implementation
•
Directories
•
Tables
•
Indices
•
A directory is the basic structural component of a VPF
database.
•
VPF directories are hierarchical.
•
Each level of a VPF database (e.g. library, coverage,
tile, etc.) is represented by a directory level.
Directories
Database
Database
Metadata
Libraries
Library
Metadata
Reference
Coverages
T hematic
Coverages
Coverage
Metadata
Feature
T ables
Indices
T ile
Directories
Primitive
T ables
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
34
Tables
•
A table is the basic organizational component of a
VPF database.
•
The inclusion of some tables in a database is
mandated by the VPF Standard.
•
The product spec may optionally require the use of
additional tables not mandated by the VPF Standard.
•
Some tables require specific columns in order to
maintain topology or pointers to other tables.
•
Additional columns may be required by the product
spec in order to describe attributes or enhance
performance.
•
VPF tables consist of two basic components:
Table structure
••
••
Table header
Table contents
Table header
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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Byte count and byte order
•
Table description
•
Narrative file name (optional)
•
Column name
•
Column field type
•
Field width (number of data elements)
•
Column key type
•
Column textual description
•
Column value description file name (optional)
•
Column thematic index file name (optional)
•
Column narrative file name (optional)
35
Table contents
•
The contents component of a VPF table contains the
actual data.
•
Data contents in VPF tables are organized into rows
and columns.
•
All rows in a table share the same column definitions.
•
Each row in a table is defined by a unique row
identifier.
•
VPF allows for indices to be implemented as part of
the data structure.
•
An index is a mechanism used to quickly sort and
identify records based on a “key”.
•
VPF allows for the following types of indices:
Indices
••
Spatial indices
••
Thematic indices
••
Join indices
••
Variable-length table indices
database design
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
•
Product structure
•
Database organization
•
Feature coding scheme
•
Tiling
36
Product structure
•
Product format
– The format of the VMap product is
based on the Vector Product Format
(VPF) data model.
– By definition, therefore, the VMap
product is relationally structured.
•
Product content
– The content of the VMap product is
based on the feature content of the
hard copy Joint Operation Graphic
(JOG) maps produced by NIMA.
– All features in the VMap product are
organized into thematic layers.
Database organization
Database
Database
Metadata
Libraries
Library
Metadata
Reference
Coverages
T hematic
Coverages
Coverage
Metadata
Feature
T ables
Indices
T ile
Directories
Primitive
T ables
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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Database level
•
The VMap product will consist of many VMap
databases, each of which will be contained on
its own CD-ROM (i.e., one database per CDROM)
•
The names for the VMap databases have been
based on the geographic area contained in the
database.
•
Each database directory must contain at least
one VMap library directory.
•
Each database directory must also contain two
required VPF tables:
– Database Header Table (dht)
– Library Attribute Table (lat)
Database: vmap
lat
dht
Library: waco
Library level
•
A VMap database can be composed of multiple
libraries, which are determined by the location of the
source JOGs
•
In addition, all VMap product discs will contain a
special-purpose library:
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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– reference
•
Each library directory must contain three required
VPF tables:
– Library Header Table (lht)
– Coverage Attribute Table (cat)
– Geographic Reference Table (grt)
•
In addition, the VMap product spec requires an
additional table for each library:
– Data Quality Table (dqt)
VPF structure – Library level
ELLAS
cat
dqt
grt
lht
Metadata
lineage.doc
libref
bnd
dq
elev
hydro
ind
Reference
coverages
tileref
phys
pop
trans
util
veg
Data
coverages
VPF structure – Library level
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
bnd
Boundaries coverage
cat
Coverage attribute table
dq
Data quality coverage
dqt
Data quality table
elev
Elevation coverage
39
grt
Geo-reference table
hydro
Hydrography coverage
ind
Industry coverage
lht
Library header table
libref
Library reference coverage
lineage.doc Lineage narrative file
phys
Physiography coverage
pop
Population coverage
tileref
Tiling scheme reference coverage
trans
Transportation coverage
util
Utilities coverage
veg
Vegetation coverage
Coverage level
•
Each VMap library (except rference) may
contain up to twelve coverages.
•
The rference library contains four
coverages.
•
Each coverage name is represented as a
directory.
•
To be VPF-compliant, each coverage
directory must contain a minimum of
three required VPF tables:
– Feature Class Schema (fcs) table
– At least one Feature Table (*ft)
– At least one primitive table
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
40
•
The VMap product specification,
however, requires the inclusion of many
optional VPF tables.
directories σε επίπεδο coverage
•
•
Οι βιβλιοθήκες πρέπει να περιέχουν τα
ακόλουθα 12 επίπεδα
bnd
Boundary
elev
dq
hydro
ind
phys
Elevation
Data Quality
Hydrography
Industry
Physiography
pop
trans
util
veg
tileref
Population
Transportation
Utility
Vegetation
Tile Reference
libref
Library Reference
4 coverages στην βιβλιοθήκη αναφοράς
libref
dbref
polbnd
placenam
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
Library Reference
Database Reference
Political Boundary
Place Names
41
VPF structure – Coverage level
hydro
char.vdt
fca
fcs
int.vdt
dangerp.pft
lakeresa.aft
end2_id.pti
end.fit
end_fit1.fti
end_fit2.fti
fac.fit
fac4_id.ati
fac_fit1.fti
fac_fit2.fti
f_code2.pti
f_code4.ati
tile2_id.pti
tile4_id.ati
fjhb
fjjb
VPF structure – metadata coverages
libref
tileref
cnd
ebr
edg
edx
esi
fcs
libref.lft
libreft.tft
tsi
txt
txx
cnd
ebr
edg
edx
esi
fac
fbr
fcs
fsi
rng
tileref.aft
tilereft.tft
tsi
txt
txx
VPF structure – tile subdirectories
fjhb
cnd
csi
ebr
edg
edx
end
esi
fac
fbr
fsi
nsi
rng
tsi
txt
txx
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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VPF structure – tile subdirectories
cnd
Connected node primitive table
csi
Connected node spatial index
ebr
Edge bounding rectangle table
edg
Edge primitive table
edx
Edge primitive variable-length index
end
Entity node primitive table
esi
Edge primitive spatial index
fac
Face primitive table
fbr
Face bounding rectangle table
fsi
Face primitive spatial index
nsi
Entity node spatial index
rng
Ring table
tsi
Text primitive spatial index
txt
Text primitive table
txx
Text variable-length index
Feature class level
•
Each VMap coverage will contain one or more feature
classes
•
Each feature class is logically composed of at least
two tables:
– A feature table
– A primitive table
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
43
•
Physically, each feature class is represented by its
own feature table, but shares a common primitive
table with other feature tables.
Feature class naming conventions
• Naming conventions are defined by the product
specification
• Names are limited to a single word of eight characters
or less
• All feature class names within a VMap coverage are
unique
• In combination with a VPF-defined four-character
suffix,
feature class names are used to form feature table
names:
–Entity node feature class name: +.pft
–Connected node feature class name:+.pft
–Line feature class name:
+ .lft
–Area feature class name
+ .aft
–Text feature class name:
+ .tft
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
=
=
=
=
=
table name
table name
table name
table name
table name
44
Feature class schema (FCS) tables
•
Feature class
name
•
Tables
•
Table keys
Feature class schema (fcs) tables
A feature class schema table stores the composition rules of
each feature class. It describes the definition for each feature
class and the way in which each table in a feature class relates
(or joins) to other tables. A feature class schema table
contains the following elements:
•
•
•
•
•
FEATURE_CLASS
TABLE1
TABLE1_KEY
TABLE2
TABLE2_KEY
the feature class name
the name of the first (outer) table of a join
the join attribute in outer table
the name of second (inner) table of a join
the join attribute in inner table
A Sample fcs table for a simple feature class
•
Simple feature classes are used in (for example) the libref coverage
id
feature_class
table1
table1_key
table2
table2_key
1
2
libref
libref
libref.lft
edg
edg_id
libref.lft_id
edg
libref.lft
id
id
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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An fcs table for a simple feature class with an rat
•
An fcs table with an rat is used in the VMap coverages with a text feature
table
id
feature_class
table1
table1_key
table2
table2_key
1
2
3
4
5
markersp
markersp
bndtxt
bndtxt
bndtxt
markersp.pft
end
bndtxt.tft
txt
bndtxt.tft
end_id
markersp.pft_id
txt_id
bndtxt.tft_id
symbol_id
end
markerp.pft
txt
bndtxt.tft
symbol.rat
id
id
id
id
symbol_id
Feature coding scheme
•
No specific feature coding scheme is defined by the
VPF standard.
•
The coding scheme to be used for the VMap product
is identified by the VMap product specification.
•
The coding scheme used allows features with similar
attributes to be grouped together.
•
All features in the VMap are coded using
the Feature and Attribute Coding Catalog
(FACC)
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
•
FACC consists of feature codes
(F_CODEs), attribute codes (A_CODEs),
and attribute code values
•
F_CODEs, A_CODEs, and attribute values
will vary between libraries and coverages
46
FACC coding scheme
•
The basic structure of FACC is a unique five-character
alphanumeric code.
•
The first character identifies the major feature
category:
A
Culture
B
C
D
E
Hydrography
Hypsography
Physiography
Vegetation
F
G
S
Z
Demarcation
Aeronautical
Terrain
General
•
The second character identifies a feature
subcategory.
•
The remaining three numeric characters assign a
unique code to each feature within the subcategory.
•
Associated with each feature is a selection of
attributes and values that provide descriptive
Attribute codes
information about the feature.
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
•
Each attribute is identified by a three-character
abbreviation or acronym (e.g., EXS – Existence
Category).
•
Attribute values provide descriptive information about
the specific type, form, pattern, activity, and so on for
each feature.
47
•
Attribute values can be either extracted or derived.
Extracted attributes can be determined directly from
the source. Derived attribute values must be
determined from other sources.
Attribute codes
FACC coding heirarchy
•
The FACC coding scheme is hierarchical in nature
AL015
BFC
010
FACC coding heirarchy
The FACC coding scheme is hierarchical in nature. The characteristics of each feature determine
the feature's attributes and (at the next lower level) attribute values. Each level of coding is
determined by (specific to) the level above it.
For example, the feature Building requires a set of attributes. One of those is the Building Function
Code BFC. The attribute BFC requires a set of values specific to the feature.
The Building in this example has a BFC attribute value of 010, but an attribute value of 010 may
not be valid for other features that require the BFC attribute.
Modeling FACC in a relational table
Coverage
F_CODE NM3 NM4 USE
Feature Class
Feature
BND
POLBNDL
Armistice Line
FA020 Name Name Null
BND
POLBNDL
Cease-Fire Line
FA030 Name Null
BND
POLBNDL
Defacto Boundary
FA060 Name Name 23
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
Null
48
Modeling FACC in a relational table
Table normalization
First
normal form
Not normal
•
Second
normal form
Etc.
All VMap feature tables have definitions that form a
normalized table when populated.
Table normalization
Null values
Field type
Null value
S
Bit pattern 10000000 00000000
I
Bit pattern 10000000 00000000
00000000 00000000
F
Bit pattern representing NaN (Not a
Number)
T
“N/A” (fixed length) or
blank (variable length)
D
Blank filled
(20 characters)
Data types used in VPF tables
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
•
T
Fixed/variable-length text
•
I, S
Integer (long and short)
•
R, F
Floating point real number (long and short)
•
B, C
2-coordinate array (long and short)
•
Y, Z
3-coordinate array (long and short)
49
•
D
Date and time
•
K
Triplet ID
•
X
Null field
Field types
INFO Data
Type
D
C (n)
I (1-16)
N (1-16)
B (2)
B (4)
F (4)
F (8)
VPF Data Types
F
*
*
*
_
*
*
_
*
R
*
*
*
*
*
*
*
_
S
*
*
*
_
*
*
*
I
*
*
_
*
*
_
*
*
T
*
_
*
*
*
*
*
*
D
_
*
*
_ = Default
* = Valid
Additional coverage-level metadata
•
Value description tables
Value description tables
Sample character value description table
ID TABLE
ATTRIBUTE VALUE
1
2
3
4
5
6
7
markersp.pft
barrierl.lft
coastl.lft
polbndl.lft
polbndl.lft
polbndl.lft
polbndl.lft
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
f_code
f_code
f_code
f_code
f_code
f_code
f_code
AL025
AL070
BA010
FA000
FA020
FA030
FA050
DESCRIPTION
Cairn
Fence
Coastline/Shoreline
Administrative boundary
Armistice Line
Cease-Fire Line
Convention Line/Mandate Line
50
Sample integer value description table
ID
TABLE
ATTRIBUTE
VALUE
DESCRIPTION
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
markersp.pft
markersp.pft
markersp.pft
markersp.pft
markersp.pft
markersp.pft
markersp.pft
coastl.lft
coastl.lft
coastl.lft
coastl.lft
coastl.lft
coastl.lft
coastl.lft
coastl.lft
coastl.lft
cpa
cpa
cpa
cpa
cpa
cpa
zv2
acc
acc
acc
slt
slt
slt
slt
slt
slt
0
1
2
3
4
5
29999
1
2
3
0
6
8
10
11
13
Unknown
Bench Mark
Horizontal
Horizontal with Bench Mark
Astronomic Position
Vertical
Unknown
Unknown
Accurate
Approximate
Unknown
Mangrove/Nipa
Marsh/Swamp
Rocky
Rubble
Sandy
Tiling Overview
•
Tiling is the process of geographically subdividing a
coverage solely for the purpose of enhancing data
management.
•
The following concepts are used in the VPF data
model in order to implement the tiling process:
••
••
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
A tile reference coverage (tileref)
Cross-tile triplet IDs
51
Untiled
Coverage
Tiled
Coverage
Tile ID=1
Tile ID=2
Tile ID=3
Tiles
Tile ID=4
Tile ID=7
Tile ID=5
Tile ID=8
Tile ID=6
Tile ID=9
VMap tiling requirements
•
The tile sizes used for the VMap Level 1 libraries will
typically be 1_ by 1_.
•
The tiling scheme will change, however, by library in
the northern and southern latitudinal parts of the
world.
•
For example, a 2_ by 2_ tiling scheme will be used in
northern Russia.
Tiling naming conventions
•
All tiles in a VPF tiled database must have
unique names.
•
The tiles in the VMap product are named using
an implementation of the GEOREF naming
convention.
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
52
•
The name of each tile is derived from the
GEOREF coordinates located at the lower left
(southwesternmost) corner of the tile.
GEOREF description
Divides the earth's surface into:
•
Twenty-four longitudinal zones 15 degrees wide each,
lettered from A to Z (omitting I and O).
•
Twelve bands of latitude of 15 degrees each, lettered
from A to M (omitting I).
•
Two hundred eighty-eight 15-degree quadrangles,
each identified by a two-letter code.
– The first letter identifies the longitude zone, the
second letter the latitude band.
GEOREF
One 15x 15grid
K
45N
15W
Q
P
N
M
L
K
J
H
G
F
E
D
C
B
A
3W
59N
1 x 1 GE ORE F = MKN Q
A B C D E F G H J K L M N P Q
15 x 15 GEOREF = M K
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
M
53
VMap Level 1 tiling scheme
•
The primitive tables for each coverage are partitioned
among tile directories.
•
The tile directories are ordered in a four-tier hierarchy
based on the GEOREF naming convention.
•
The first, second, and third tier subdirectores contain
only pointers to the fourth subdirectory, where all
primitives are stored.
•
The VMap data dictionary contains the following
Data dictionary contents
information:
••
Data structure for metadata and feature tables
••
Allowable content range for metadata and
feature tables
••
Brief description of each feature table
••
Examples of the records that may be contained
in the actual tables
coverage structure (example)
•
The VMap features listed below are contained within
three separate feature class tables in one coverage
(util) in VPF:
F_CODE
AT010
AT080
AD010
AQ116
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
Feature
Disk/Dish
Communication Tower
Power Plant
Pumping Station
VPF Feature Class
commp.pft
commp.pft
powerp.pft
pumpingp.pft
54
VPF structure and metadata tables
•
Output database, library, coverage, tile
and any required metadata tables will be
created if they do not already exist.
•
Database-level tables:
– Database Header Table (DHT)
– Library Attribute Table (LAT)
•
Library-level tables:
– Geographic Reference Table (GRT)
– Library Header Table (LHT)
– Coverage Attribute Table (CAT)
•
Coverage-level tables:
– Feature Class Schema Table (FCS)
– Feature Class Attribute Table (FCA)
(with FIT option only)
ΕΠΑΓΕΔ’97 – ΠΑΡΑΡΤΗΜΑ 7Β
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