International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
space for the sheet. Since DLM required by MPS is not
equivalent to data model of VMAP L-1, the database schema of
VMAP L-1 is adapted to make it an input to the software. Data
is symbolized regarding DCM. Model errors, cases contrary to
DCM and incompleteness in database schema are determined
and removed to finalize editing on database.
As graphic detail and density of data in VMAP L-1 is more than
the geometric and thematic content of JOG series, cartographic
generalization is necessary to visualize the data as JOG. In order
to improve graphic readability and produce a map according to
JOG specifications, VMAP L-1 data is generalized by using
conceptual and particularly ^ cartographic (graphic)
generalization operations such as simplification, exaggeration,
replacement, classification, and aggregation.
[Initially both ED50 and WGS84 datum information has been
shown on the sheets by means of depicting ED50 grid as a
secondary grid with tick marks along the border of sheet. In
order to prevent the confusion of reference information, it has
been provided a coordinate conversion note between datum
ED50 and WGS84 in the marginalia (surrounding elements).
Datum transformation information for each JOG sheet among
ED50 and WGS84 are provided by Geodesy Department
(GCM). And magnetic declination at epoch 2000 which are
calculated from magnetic observations done on field by
Geodesy Department of GCM.
Contour intervals are determined due to the steepness of the
region and availability of contour. Selected standard contour
intervals for index contours are [100-500-1000-1500-2000 ...],
contours not in standard interval are [40-200-400-600-800-
1000 ...]. Visual air charts have a variety of terrain elevation
cues, both for navigation and for alerting the pilot to danger.
Contours and spot elevations give accurate values; elevation
tints point out the highs and lows; shaded relief emphasizes
every ridge and valley, helping the chart mimics the view out of
the cockpit.
MEFs are calculated based on relief, and information about
vertical obstacles from SAA, NGA, AirForce. MEFs give the
disoriented or smoke-blinded pilot an instant target to climb out
of trouble (NGA 1995-2, DMS 2002). MEFs are shown in each
quadrangle bounded by the projection's lines of latitude and
longitude (on JOGs 15-minute quadrangle). MEFs are based on
the highest known feature in the quadrangle, including terrain
(ridges, mountains, hilltops) and obstructions (trees, towers,
buildings, antennas etc.). After transforming labels coded in
ASCII into Turkish, the base map is formed. This process is
done due to the graphic representation of Populated Places DB
of Turkey (PPDB T) (Torun, 2002). Names and other
descriptive information are labelled due to typography model
which is developed based on FACS feature code (Figure 2).
Control of data editing process is done by taking print-outputs
of layer which are closely related to each other. Consistency of
all thematic layers is maintained by checking cross-layer
compatibility such as relief-hydrography, population-
hydrography-vegetation ^ and transportation-hydrography-
physiography.
302
The map face (basemap) is created by using the tools regarding
rules, constraints, definitions and models. The map face
contains all the graphic and text information with reference,
Different parameters and procedures are used for ground and air
versions. Tools for visualizing VMAP LI as a ground map are
all implemented by our team by obeying the structure of MPS
JOG Project
Data Frame (Layers) Rules, Definitions and Models
-Extended VMAP LI
-Graticules and grids
-Magnetic and isolines
-Depth data
-Aeronautical information
-PPDB_T
-Digital Landscape Model (DLM)
-Digital Cartographic Model (DCM)
-Typography Model
-Symbolization Model
-Symbols and Colors
-Product definitions
-Page Layout definitions
-Map element placement rules
-Marginalia definition
v -Graphic elements
Tools
-ESRI PLTS/MPS
-Data Management Tools to
generate DLM
«4— —| -Symbolization
-Graphic Processing
v -Generating map elements
for Turkish version of JOGs
Marginalia
(Map Frame)
Final Map a
Figure 2. Process Model of Cartographic Visualization
Map face
(Basemap)
software. The sequence of visualization is area, line, point and
labels. If the lines are visualized with case, those are visualized
with respect to defined rules which yields cartographic
aesthetic. These tools are running with the core software in a
friendly manner.
After graphic operations, surrounding information (marginalia)
are created. These are descriptive information about sheet,
symbol legend, aeronautical symbol legend, location diagram,
conversion table for units, referencing information about
military grid, bar scale, diagram for horizontal and vertical
reliability, colours of elevation tints, glossary, caution and
disclaimer notes, georef index, copyright and producer notes.
Location Diagram is a graphic element depicting location of a
sheet on a reference map and neighbouring sheets and the charts
containing this particular JOG at lower scales. In Figure 3,
Location Diagram created by using a customized tool with
descriptive text. Graphic and surrounding graphics are compiled
to generate Postscript graphic file for reproduction. The
compilation is employed according to rule base for compilation
for different cartographic visualizations; such as air or ground
chart, Turkish or English as primary language etc. Almost all of
the rules, models and definitions in DCM of MPS for map
layout and marginalia arc customized due to specifications of
GCM. The tools creating graphic elements in marginalia are all
re-designed, implemented and embedded in MPS software.
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