HEADS UP DIGITIZATION- ON THE FLY- GIS

1. HEADS UP DIGITIZATION
“It is defined as the manual digitization by tracing a mouse over features displayed on a
computer screen, used as a method of vectorizing raster data (ESRI, heads-up digitizing)”.
INTRODUCTION
Digitization of the geographic maps is confusing and time consuming process. If the same
person is digitizing the data and converting it into the GIS, the way is not so important, but the
result is. However, for parallel digitization, which means digitization of two or more geographic
maps by different users at the same time, user intervention brings confusion problems while
converting digitized data into the GIS. For this reason, before initiating the project, the
standards of geographical map digitization should be well performed. A geographical map can
contain limited number of common features such point, line, polygons etc. measurements
(Kansu, 2006). To digitize these features, a task bar is prepared for use in any digitization
software that standardizes the attributes of digitized data. This task bar provides the attributes
of common geographical features. While digitizing, user finds the icon of the feature on the task
bar and pushes that button. The attribute is copied into the PC’s ram and user pastes it into the
necessary field.
TYPES OF DIGITIZATION
1. Heads Down Digitizing or Manual Digitizing
Digitizing on the table or tablet and working with a heads down posture. This type of digitizing
is often tedious and tiring to the operators.
2. Heads up Digitizing (old and new method)
 This digitization works as mouse on a screen to digitize the paper maps, aerial photos, or
other images on computer screen.
 In the old method, the operator traced map features on a transparency and attached this
map to the computer screen (UNSD, 2010)
 In the new method of heads-up digitizing, a scanned map image is used digitally to trace the
outlines into a GIS layer
HEADS UP DIGITIZATION (DIGITIZING NEW FEATURES)
Operator uses a Raster-scanned image on the computer screen i.e., a scanned map, air photo or
satellite image as a backdrop (ESRI, HowTo: Digitize or create lines and polygons without

2. clicking at every vertex). Operator also follows lines on-screen for working in vector mode. An
arrangement to digitize features on screen is listed below:
a) Create new point, line or polygon shapefile in ArcCatalog
b) Add Spatial Reference Information (optional)
c) Add new shapefile in ArcMap
d) Start editing (Editor toolbar)
e) Digitize feature shapefile to add features and attributes
f) Stop editing
g) Save edits (UNSD, 2010)
ADVANTAGES OF DIGITIZATION
 One advantage of heads up digitization is to simplify the digitization process.
 It is much faster than non standardized and unorganized digitization (Kansu, 2006).
 The digitizing with the help of different softwares may be done by people having no
geographical background.
BIBLIOGRAPHY
 ESRI. (n.d.). heads-up digitizing. Retrieved 2015, from ESRI Support:
http://support.esri.com/en/knowledgebase/GISDictionary/term/heads-up%20digitizing
 ESRI. (n.d.). HowTo: Digitize or create lines and polygons without clicking at every vertex.
Retrieved 2015, from ESRI SUPPORT: Knowledge Base - Technical Articles:
http://support.esri.com/em/knowledgebase/techarticles/detail/29694
 Kansu, E. V. (2006). HEADS-UP DIGITIZATION OF GEOLOGIC MAPS USING AN INDEPENDENT
USER INTERFACE AND CONVERTING INTO THE GIS. PS WG IV , 1-3.
 UNSD. (2010). Constructing an EA-level Database for the Census. USA: UNSD-CELADE
Regional Workshop on Census Cartography for the 2010 Latin America’s census round.

3. ON THE FLY
“In ArcMap software, data is displayed on a map using a specified coordinate system. When
additional data is added to the map does that not use the same coordinate system, ArcMap can
project this data "on the fly." That is, ArcMap can automatically transform the data's projection
system to be the same as that used for the map (Shekhar et al, 2008).”
INTRODUCTION
There are many public and private mapping organizations that have holding of digitized maps at
different scales and thus are interested in linking these together so that updates can be
propagated automatically from more details to less detailed representations, allowing
increasemental updates (Lagrange, 1995).
PROPERTIES
Some of the important on-the-fly generalization properties are listed below:
 A temporary, reduced scale map is generated for visualization purpose from spatial data
base.
 Use for the maps which do not meet the user preferences and the technical display
specifications.
 The scale of the resulting map may vary and is not predefined.
 The resulting map displayed with a few processing seconds (Kurland and Gorr, 2007).
APPLICATION (ON THE FLY)
On the fly map generalizations is a developing research area as the development of appropriate
techniques targets a variety of applications which have in common that they are highly
interactive for real time visualization with adaptable scale and content. A few examples of such
applications are tabulated below:

4. APPLICATION REMARKS
WEB MAPPING The evaluation of web mapping has provided the initial setting
that prompted the need for on the fly generalization capabilities.
Web mapping greatly requires on the fly generalization for
displaying different area’s digitized maps.
ADAPTIVE ZOOMING Adaptive zooming requires on the fly generalization for the
adjustments of maps, its contents and symbolization to target
scale in consequence of a zooming operation.
MOBILE CARTOGRAPHY Mobile devices are bound to impose more stringent technical
limitations than commonly encountered in cartography which
includes low resolution problems, small display screen size, low
bandwidth, unreliable network connectivity etc. that is why,
mobile devices requires on the fly generalization to display
appropriately generated cartographic maps.
REAL TIME DECISION
SUPPORT SYSTEM
GIS used a great deal as tools for decision support. While most
uses of spatial decision support system (SDSS) don’t have real
time requirements. So, new applications have recently started to
appear that do involve SDSS in real time data feeds.
Examples includes, emergency services dispatching, evacuation
route planning, disaster management etc.
(Shekhar et al, 2008)
BIBLIOGRAPHY
 Lagrange, J. P., Weibel, R. and Muller, J. C. (1995). GIS And Generalisation: Methodology
And Practice. CRC Press.
 Kurland, K.S. and Gorr, W. L. (2007). GIS Tutorial for Health. ESRI, Inc.
 Shekhar, S. and Xiong, H. (2008). Encyclopedia of GIS. Springer Science & Business
Media.