International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
2.1 Conceptual View of VMAP Database for Visualization
of JOG
Aircrew needs to know all kind of information about every
phase of a mission, before they fly. Those information are
weight and balance, weather conditions, performance figures,
flight characteristics and navigation data. Aeronautical charts
are one way of providing the navigational information to the
pilot. Each different type of flying can require a different type
of chart: high-altitude or low, visual (VFR) or instrumental
(IFR) navigation, departure, cross-country or approaching for
landing. Instrument Flight Rules (IFR) products are FLIP
Enroute Charts. Visual Flight Rules (VFR) products used for
visual flight are JNC at scale 1:2000000, ONC at scale
1:1000000, TPC at scale 1:500000, JOG Air at scale 1:250000,
SAC at scale 1:500000 and at 1:250000 (DMS 2002). Visual
flight refers to flight operations in fair weather, under VFR,
where the pilot is able to see the ground well enough to
navigate and to see and to avoid other aircraft.
Visual aeronautical charts, such as JOG Air, portray
aeronautical data on a basemap of the charted area. This
basemap includes the relief (mountains and valleys), drainage
(streams and shorelines, and cultural (man made) features of the
area, drawn and symbolized so that the pilot can easily spot the
mapped landmarks and compare them to the features seen from
the cockpit.
In JOG series, in addition to reference system and projection
information, information about hydrography, populated places,
transportation, physiography, relief, administrative boundaries,
industry and utilities are presented. Relief is shown by means of
contour, spot heights, elevation tints and shaded relief.
Contours are generalized in JOGS. Elevation tints and relief
shading help the pilot locate the main ridges and valleys in JOG
air. Streams and roads are portrayed for their landmark value.
Drainage is extremely detailed. Vegetation is symbolized in all
areas.
There are some differences between ground and air series due to
their functionality. In air charts, other than ground maps,
information about Maximum Elevation Figures (MEF) in every
15'x15' graticules, magnetic isogons, aerodromes, heliports,
radio navigation aids, vertical obstructions, power lines and air-
defence identification zones (ADIZ) are portrayed in the first
order of visual hierarchy with respect to other feature types.
Height information is expressed in meters in ground version and
in air version they are marked in feet for pilots.
Accuracy of JOGs are in category 2 standards of NATO.
Horizontal and vertical accuracies of JOGs are 125 meters and
50 (half the contour interval) meters respectively (NGA 19951,
NGA 1995-2).
2.2 Data sources of JOG maps (Extended VMAP L-1
database)
Geographic extent of VMAP L-1 database is global. Data is
continuous and seamless. VMAP database is a vector-based
product implemented in VPF. Each layer contains thematically
consistent data. The VMAP thematic layers are organized into
ESRI ArcInfo coverages contained in VPF (Vector Product
Format) libraries. VPF is a subset of DIGEST (Digital
Geographic Information Exchange Standard) FACC (feature
attribute Coding Catalogue) (NGA, 1995-1, Ohlhof, et.al.
2000).
VMAP family of databases is used to extract digital geographic
information, to produce analogue and digital maps for military
purposes. In Table 1, types of VMAP products, their scale and
date of availability are given (Ohlhof et.al., 2000). Data source
of VMAP L-1 is JOG series which has a density of detail of
medium scale maps in NATO Standardization Agreements
(STANAG). This product is designed to support GIS
applications with geographic data at medium resolution. Based
on this collection density, the scale of hard-copy product is
1:250 000. According to this compatibility, VMAP L-1 is a
model of small world containing the phenomenon such as
boundaries, data quality, elevation, hydrography, industry,
physiography, population, transportation, utilities, and
vegetation as separate ten feature classes in medium scale maps
(NGA 1995-2). Feature class is a group of features sharing a
homogenous set of attributes. There are five feature class types
in VMAP L-1 namely point, node, line, area and text. Rules and
minimum size of features collected from source materials are
defined in NGA 1995-1.
Table 1. VMAP databases and maps produced from
these databases
Product Name Paper Product | Availability
Scale
VMAP LO 1:1000000 Digital Chart of the
World (DCW-2001)
VMAPLI 1:250000 2004
VMAPI2 1:50000 On demand
Urban VMAP City Map On demand
Being produced by several NATO countries as a co-production,
the VMAP LI database is going to be finalized in 2004. VMAP
L-1 database is generated by collecting data from scanned JOG
sheets, rasterized topographic maps, thematic maps, remotely
sensed images, contour lines in digital format and sources from
other databases. Graphic data —geometric models of features- is
mainly extracted from panchromatic mono SPOT images with
10 meters pixel size. However stereo images are used in case of
uncertainty in image interpretation as a control of data
collection. Thematic information is collected from JOGs and
large scale topo-maps. And, aeronautical information is taken
from AAFIF, DVOF and documents for aero-navigation of
State Airport Authority (SAA) and Turkish Air Force (TAF).
AAFIF (Automated Air Facility Information File) contains
information about physical characteristics of airfields and
DVOF (Digital Vertical Obstruction File) comprises a list of
man-made vertical obstructions such as towers, buildings, radio
masts and power lines. Toponomy are collected from topo-
maps, former JOG editions, PPDB T (Populated Places
Database of Turkey) which stores information about populated
places, their population and location.
2.3 Production of JOG Series by Using VMAP L-l
Database
Former editions of JOG series (firs edition 1971-1973 and
second edition 1983-1987) are produced by means of
cartographic generalization of topographic maps at scale
1:100000 which are extracted from base topographic maps at
scale 1:25000 and addition of aero-information. Vector Smart
Map Level ! (VMAP L-1) database is presently used
production of air and ground series of third edition. The source
of VMAP L-1 is the basic data of JOG series, density of which
is appropriate for density defined for middle-scale. This
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