The Topographic Database (TBD) is the official
name of the coherent system of data acquisition and distribution at the
national level, which operates basing on appropriate legal regulations.
The objective of the TBD development
is:
·
To
perform functionality of delivery of updated topographic data,
·
To
avoid multiple acquisition and updating of the same data by many users,
·
To
ensure updated topographic data for topographic and thematic map making systems.
Data contained in the
TBD Database may be the starting point for development of spatial information
systems for various governmental and local government institutions and they may
be utilised by systems developed within the private sectors.
Gauss-Krüger projection has been assumed in the „1992” System, in
the meridional zone covering the entire area of
Poland, (more than 10°), with the axial meridian L0 = 19°
E, for which the length scale equals to 0.9993 (length deformation -70 cm per
1km). Similar deformations occur at the Eastern and Western edges of Poland.
Lines of the null deformations are located within the distance of approximately
240 km from the axial meridian.
The
origin of the rectangular co-ordinate system is the point of crossing of projection
of the axial meridian 19°
(X axis) with projection of the Equator (Y axis), providing that coordinates of
this point are: X0 = -5300 km, Y0 = 500 km.
Such assumptions allow
to develop spatially continuous Topographic Databases, without the necessity to
divide them into projection zones.
The vector topographic database is
administered and organised by means of GIS technology which allows for
efficient searching and analysis of data, as well as for individual or common cartographic
presentation of the digital terrain model, digital orthophotomaps
and vector data.
The geometric accuracy of representation of objects in the TOPO
component first of all depends on possibilities of object interpretation on the
orthophotomap and on the topographic map at the scale
of 1:10 000. The total mean error of position of points which are well visible
on the orthophotomap, should not exceed 5 m.
Sources of data
The basic sources of geometric data for the TBD
database are: digital orthophotomaps, field
reconnaissance, data from large-scale databases (the basic map, land register
maps). The additional source of data are existing sheets of the topographic map
at 1:10 000 scale, documents, which contain digital records of the topographic
map of Poland, 1:10 000 scale (the so-called, skeleton version), drawing materials
of names together with lists of names, drawing materials of spot heights etc.
Data collected in the TBD Database may be the basis for development of spatial
information systems.
All objects should be introduced according to
their real field position, with maintenance of all required topological
relations.
Besides, data for the
TBD Database may be acquired from the following sources:
1)
Selected data from the GEOS Database (the Databank of Geodetic control
networks) – CODGiK (the Geodetic and Cartographic
Documentation centre),
2)
Selected data from the PRG Database (The State Register of Borders) – CODGiK,
3)
The Bank of Geographic Names – CODGiK,
4)
The Databank of Administration of Public Roads,
5)
The Databank of Water Management Offices,
6)
The Hydrographic Database of Poland,
7)
The VMap Level 2 Database,
8)
The list of identifiers and names of localities (GUS – The Main
Statistical Office),
9)
The Central Catalogues of Streets (GUS),
10) The 1:50 000 Topographic
Map (civilian version),
11) Forest maps.
4.1.2 The NMT component
The NMT component is the
digital terrain model database recorded according to division into sections
(single map sheets or sets of map sheets). The database is created in two
forms, as measurement data and useful data. The digital terrain model is an important
element of the “TBD resources”, with respect to external users of the TBD
database, as well as for creation of digital orthophotomaps
and development of topographic maps. The NMT database is created following
orders for the development of the Topographic Database (TBD) or received to the
“TBD resources” from other projects, if they meet quality criteria and
technological requirements defined in The Technical Guidelines of the
Topographic Database (TBD).
4.1.3 The ORTO component
The ORTO component is the database of digital orthophotomaps in sectional division (single map sheets).
The basic form is the true-colour orthophotomap,
recorded in RGB (three-layer) mode.
The ORTO component is created following orders
for the development of the topographic Database (TBD) or received to the
resources of the TBD orthophotomaps, made in other
projects, which meet the quality criteria and technological requirements
defined in The Technical Guidelines of the Topographic Database (TBD). The area
module of the orthophotomap is an area described by
means of the smallest rectangle of sides parallel to X,Y axes of the “1992”
System, which contains the standard section of the Topographic Map of Poland at
the scale of 1:10 000 (the so-called, MBR – Minimum Bounding Rectangle),
enlarged by the margin of 250 m width. Within the area module and the entire
block, for which orthophotomap modules are developed,
the digital orthophotomap should be unified with
respect to tones, colours and contrast and it should create the continuous
images without improper visual effects.
5. Metadata
Technical Guidelines of the Topographic
Database assume that – regardless for the spatial coverage and type - for each
newly created set of data, a metadata file should be created, which should be
used for creation of a metainformation module in the
Topographic Database Management System.
Metadata should be understood as data
concerning objects or data sets, which create the resources of the TBD. They
are collected for the needs of correct identification of data files and
appropriate evaluation of data usefulness from the user’s point of view.
Metadata have limited relations with individual
objects of the vector topographic database (TBD). Metadata cover the data of
acquisition of an object, the up-to-datedness status, the last updating date,
the identifier of an operator who introduced or updated the object, the source
of geometric and descriptive data, the accuracy of geometric description (the
accuracy class) and the way of the object representation.
6. Development of topographic maps using the
TBD data
6.1
Differences between rules of editing topographic maps in the TBD standard and
topographic maps corresponding to the obligatory technical instruction
Editing rules concerning
topographic maps according to the TBD standard are slightly different than
rules concerning topographic map making, resulting from the obligatory
technical instruction.
Those differences results mainly from:
·
intention
to maintain many objects in their real positions on the TBD standard map,
·
intention
to limit various methods of geometric representation of the same classes of
objects (e.g. buildings represented by means of area symbols only),
·
intention
to introduce regular patterns and line styles (e.g. introduction of regular
patterns – a symbol of forests),
·
renouncement from the existing, detailed
presentation of some terrain elements (e.g. pavements),
·
necessity
to present data on the new quality (e.g.
in case of two-roadway roads the necessity to present two axes instead of one
axis of a roadway),
·
intention
to construct symbols which allow to simplify generation from the database
(renouncement from all “tentacles” in symbols, e.g. a symbol of a bridge or a
shed).
Therefore
topographic maps in the TBD standard are characterised by simplified graphics
comparing to maps made according to the obligatory instruction. First of all,
cartographic symbols have simplified forms, and repeatable patterns are
applied. Less attention is paid to application of editing rules which concern
symbol displacement, deletion of a part of a symbol or replacement of a part of
a given symbol by another symbol.
Table. 6.1 Differences between
selected symbols of topographic maps following the TBD standard and maps made
according to the obligatory technical instruction
|
Symbol description |
Topographic
map in the TBD standard |
Topographic map corresponding to the
instruction |
|
Administrative
borders |
|
|
|
Highway |
|
|
|
Railway
bridge |
|
|
|
Deciduous
forest |
|
|
|
Coniferous
forest |
|
|
6.2
Stages of topographic maps development basing on the TBD vector data
The process of generation of
topographic maps, following the TBD standard, may be divided into the following
stages:
- selection
of vector data from the TBD,
- generation
of additional cartographic objects (as land use outlines),
- division
into map sheets,
- generation
of contours from the NMT,
- development
of a map frame and marginal information,
- generation
and editing of labels,
- development
of graphics following the guidelines (library of symbols).
Fig. 6.1 Topographic map 1:10 000
following the TBD standard
In order to make the topographic map
in accordance with the technical instruction, the following actions should be
performed:
- additional
generalisation (e.g. modification of representation of small buildings,
from surface to point presentation),
- displacements,
breaking of objects, e.g. sections of borders, buildings located close to
roads, power supply lines in built-up areas,
- acquisition
of additional data, e.g. edges of pavements,
- exchange
of libraries of symbols, utilisation of irregular patterns (Gotlib 2003).
Fig. 6.2 Topographic map 1:10 000
made according to the obligatory technical instruction
Final remarks
The Topographic Database
is a source of new generation of data comparing to the existing topographic
maps. It is not only the basis for development of civilian topographic maps,
but it is also the reference database for many thematic works. Together with
the VmapL2 and BDO databases it is the basis for development of the
infrastructure for spatial information in Poland. At present, works aiming at
unification of conceptual models of those databases, in order to allow the
direct data flow between them, are continued. Works concerning the simplified
version of the Topographic Database for areas of lower economic importance,
have been also commenced.
The Topographic Database
is the foundation for modern systems of topographic map making, where the
development of cartographic projection is highly automated. The TBD highly
simplifies the process of topographic map making for the needs of multi-sheet
printing. It also allows for generation of maps of simplified graphics,
commissioned for selected areas. Together with the Topographic Database
development, new possibilities of topographic data visualisation appeared, for
example presentation in perspective projection, with orthophoto
or digital terrain model background.
References
1. The General Surveyor of
Poland, 2003, Technical
Guidelines, Topographic Database – version 1, the Head Office of Geodesy
and Cartography. Główny
Geodeta Kraju, 2003, Wytyczne techniczne, Baza danych Topograficznych
– wersja1, GUGiK,
2. The General Surveyor of
Poland,1998, Rules of editing 1:10000 topographic maps,
Patterns of symbols, Technical Instruction, the Head Office of Geodesy and Cartography. Główny
Geodeta Kraju, 1998, Zasady redakcji mapy topograficznej w skali 1:10 000. Wzory znaków, Instrukcja techniczna, GUGiK,
3. Gotlib D., 2003, Topographic Database versus topographic map making, Archives of Photogrammetry, Cartography and Remote Sensing, Baza Danych Topograficznych a produkcja map topograficznych, Archiwum
Fotogrametrii, Kartografii i Teledetekcji, vol. 13a, pp.
69-75,
4. Lexicon of the Polish Association for Spatial Information, Leksykon Polskiego Towarzystwa Informacji Przestrzennej,
http://www.ptip.org.pl.