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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
compatibility enables to use VMAP L-1 for JOG production.
JOGs are used as a basic data source for other air and
topographic maps at smaller scales.
The third edition of JOG series are produced by means of
database — driven cartographic visualization = methods.
Visualization based on database driven cartography allows not
only produce to different types of cartographic products, but
also maintains consistency of data within database.
Visualization is done in a semi-automated manner such that;
e some of the processes are done by computer,
e some are firstly done by computer than edited by
cartographer,
e some are done interactively by cartographers.
Because of diversity of information on JOGs, the cartographers
in JOG production are trained on aeronautical cartography. The
training is provided by Mobile Training Team of Defence
Mapping School of NGA. Computer skills of cartographers on
the software for map production work flow are enhanced several
times before and during the period of process.
2.4 Digital Terrain Model and Digital Cartographic Model
for JOG
Digital Landscape Model (DLM) consists of data model, data
dictionary, rules, condition, constraints and relationships (Kraak
and Ormeling 1996). DLM is a subset of conceptual schema of
VMAP L-1 database. However, this schema is extended with
necessary dimensions (attributes) for the need of cartographic
visualization. In addition to extended VMAP L-1 database,
aeronautical information, magnetic and normal magnetic
models, digital depth model of the seas surrounding Turkey and
Populated Places Database of Turkey (PPDB_T) are the data
content supporting JOG.
Data dictionary and rules for data collection are strictly defined
in MIL-J-80100 (DMA) of NGA (NGA 1995-2). The feature
classes and features are coded by means of DIGEST FACC of
NATO.
The content, accuracy, density and symbolization rules of
spatial/non-spatial data are defined in Digital Cartographic
Model (DCM) (Kraak and Ormeling 1996). DCM is
implemented in the conceptual model of extended VMAP LI
database for visualizing JOG. The rules and knowledge are
stored in a logical model of extended VMAP LI database. The
DCM is constructed by combination of former editions of JOGs
by GCM, JOG specifications by GCM and NGA, STANAGs,
symbolization rules and rules defined in ESRI PLTS/MPS.
Previous editions of JOGs, JOG specifications and STANAGs
are used for generating and compiling surrounding information
and graphics (NGA 1995-2, NGA 1995-3, STANAG-3675
2000).
There are two main approaches to construct spatial databases
for cartographic visualization. First one is preparing a database
for cartographic use only. The database is transferred into a
visual model by means of batch or manual editing processes and
adding cartographic features prepared for certain type of maps.
The second approach enables the user to generate multiple
views of the database based on a DCM. This method is more
generic and flexible providing definition of map composition,
colours, symbols, representation rules, sequence of processes
301
etc (Frye, C. et.al, 2003). Integrity and visualization rules of
DCM are introduced in rule-bases. And, constraints are
modelled as processes in the software. Definitions expressed in
knowledge base are utilized as a process during implementation.
All the map elements except data frame (basemap) are
encapsulated in data and map processing functions. Map
elements are located due to product type (air/ground) and size
of graphic elements created based on information for each map.
Therefore, the user doesn't need to re-arrange them. The tools
and models customized and extended MPS software are
employed producing cartographic visualization of VMAP LI
database.
However, the DCM of the software used is based on FACS of
NGA. The database schema is extended for cartographic
visualization with necessary attributes. These attribute values
are calculated and populated as a function of other attribute
values in the same feature class for visualization model.
3. APPLICATION
Visualization of VMAP database is done by enriching the
visualization model of ESRI PLTS/MPS in two ways: first
customizing the open source tools for the needs and national
mapping requirements in the frame of NATO STANAGs;
second, generating new tools and methods. The visualization
system, analogue map production workflow, data content,
visualization model and brief explanation of implementation are
expressed in this chapter.
3.1 Workflow of JOG Production
Digital JOG production workflow from VMAP L-1 database is
given in Figure 1. Firstly, data with extent of a sheet are cut and
extracted from VMAP L-1 data library. Errors due to cut are
corrected and data is transformed into UTM projection from
geographic coordinates. Then, descriptive information of the
sheet such as name of the sheet, country, vertical unit,
producing company, copyright etc. are defined for a project
Sheet Definition
Symbolization
Generalization- Surrounding
| Editing- elements
Annotation
]
Visual integration
of shaded relief et
; : Editing
elevation tints and
; (OK)
vegetation
Map compilation
Figure 1. Workflow for Analogue
JOG production