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DOCUMENTATION OF META DATA MANAGEMENT IN CASE OF NATIONAL GEODETIC NETWORK
MAP OF ETHIOPIA
Acknowledgement
We would like to thank you GOD for giving the desired efficiency to complete this project.
There is also a long list of people from various fields and different backgrounds who
contributed with their knowledge and experience all being of inestimable significance in
accomplishing this project.
Firstly, we would like to thank DR Aramde Fetene and MR Kibrom Hailu, Programme lecturers
for the course of GIS for landscape architects, who inspired and encouraged us to take the
chance to do GIS beyond click- click and being practical. Their advices and ideas on how to
start such a project were of high importance.
We are very grateful to urban planning students (Solomon Abebe and Oliyad), for technical
assistance and sharing data that gave hint during our work. Finally, we would like to express
our gratitude to everybody who had even the smallest contribution to our project.

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Contents
Acknowledgement...................................................................................................................................1
List of figures..................................................................................................................................................4
List of tables...................................................................................................................................................4
Abstract..................................................................................................................................................5
1.1 Back ground of the study.................................................................................................................6
1.2 objective of the study .......................................................................................................................6
1.3 scope of the study ............................................................................................................................6
1.4 Limitation of the study......................................................................................................................6
2. Literature Review....................................................................................................................................7
2.1. Geodetic network.............................................................................................................................7
2.2 Benefit of geodetic network.............................................................................................................9
2.3 Network Formation .........................................................................................................................10
2.2.1 Triangulation...............................................................................................................................10
2.2.2 Trilateration ................................................................................................................................11
2.2.3 GPS..............................................................................................................................................12
2.3 Study Area.......................................................................................................................................13
2.4 Geodetic network in Ethiopia........................................................................................................14
3. Methodology ..........................................................................................................................................15
3.1 Secondary data...............................................................................................................................15
Process .................................................................................................................................................18
4. Discussion and Result..........................................................................................................................23
4.1 Surface analysis..............................................................................................................................27
4.1.1 Contour .......................................................................................................................................28
4.1.2 View shed....................................................................................................................................29
4.1.3 Slope............................................................................................................................................32
4.1.4 Aspect..........................................................................................................................................33
4.2 Hydrology.........................................................................................................................................34
4.2.1 Flow Direction.............................................................................................................................35
4.2.2 Flow Accumulation......................................................................................................................36
4.2.3 Stream to Feature .......................................................................................................................37
4.2.4 Stream Link .................................................................................................................................38
4.2.5. Stream Order .............................................................................................................................39
4.2.6 Pour Point ...................................................................................................................................40

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4.2.7 Water shed..................................................................................................................................41
4.2.8 Water Basin.................................................................................................................................42
5. Map revision ..........................................................................................................................................43
6. Democratization ...................................................................................................................................43
7. Conclusion .............................................................................................................................................44
8. Recommendation..................................................................................................................................45
Reference...................................................................................................................................................46

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List of figures
Figure 1 sketch illustrating the concept of earthquake early warning...............................................10
Figure 2 triangulation coordinate measurement source internet ......................................................10
Figure 3 Trilateration coordinate measurement source internet........................................................11
Figure 4 Satellite constellation GPS satellites orbiting with an inclination of 55˚ to the equator ..12
Figure 5-GPS monitoring stations around the equator and the main control station in Colorado 12
Figure 6- Simple map of Ethiopia and neighboring countries. ...........................................................13
Figure 7– National geodetic network map taken from National Atlas map of Ethiopia ..................15
Figure 8 digitizing reference points ........................................................................................................17
Figure 9– Hiran station fixed by Ground surve.....................................................................................23
Figure 10– Trig/Hiran station...................................................................................................................24
Figure 11– Hiran Trilateration line ..........................................................................................................25
Figure 12– overall network map..............................................................................................................26
Figure 13– Contour Line Map..................................................................................................................28
Figure 14- view shade map 1..................................................................................................................30
Figure 15– view shade map 2 .................................................................................................................31
Figure 16 – slope map (in %) ..................................................................................................................32
Figure 17– Aspect map ............................................................................................................................33
Figure 18– Flow Direction........................................................................................................................35
Figure 19– Flow Accumulation................................................................................................................36
Figure 20– Stream Feature Map.............................................................................................................37
Figure 21 - Stream Link............................................................................................................................38
Figure 22 – Stream Order Map..............................................................................................................39
Figure 23– Pour Point Location Map......................................................................................................40
Figure 24– Water Shed Map ...................................................................................................................41
Figure 25– Water Basin Ma.....................................................................................................................42
List of tables
Table 2 - 1 - x, y coordinate for Geo referencing .................................................................................16

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Abstract
A geodetic control network is the wire-frame or the skeleton on which continuous and
consistent mapping, Geographic Information Systems (GIS), and surveys are based.
Traditionally, geodetic control points are established as permanent physical monuments
placed in the ground and precisely marked, located, and documented. With the development
of satellite surveying methods and their availability and high degree of accuracy, a geodetic
control network could be established by using GNSS and referred to an international terrestrial
reference frame used as a three- dimensional geocentric reference system for a country.

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1. I NTRODUCTION
1.1 Back ground of the study
Being the ground for all types of location determination, a reference network is the most basic
infrastructure in a country and has a crucial role in a country’s development and growth. One
of the fundamental tasks of geodesy is the building and maintenance of geodetic reference
networks. Geodetic networks are comprised of a set of well-defined and monument geodetic
markers distributed on Earth’s surface. They form the basis for investigations of the shape,
dimension and gravity field on the Earth.
1.2 objective of the study
The aim of this project is to generate spatial data, Meta data and geo data base and create a
reliable, accurate reference network connected with the existing local frame of Ethiopian
national geodetic and level network.
Democratizing the output spatial data in cartographic aspect in order to make it accessible to the
public for those in need of the information without any charges.
1.3 scope of the study
Updating the Ethiopian network using the reference of the old national geodetic network from
the book National Atlas of Ethiopia, January, 1988, 1st edition and make it accessible for the
public without any charge required.
1.4 Limitation of the study
• Unable to access through downloading Ethio DEM.
• Shortage of time for proper fulfillment of the assignment and acquire the desired output.
• The fixed contour interval limited as to label the contour.

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2. Literature Review
2.1. Geodetic network
A geodetic control network is the wire-frame or the skeleton on which continuous and
consistent mapping, Geographic Information Systems (GIS), and surveys are based. To
understand the function of geodetic control, we have to realize that a map or a plane survey is
a flat representation of the curved world. If we want the maps to become an authentic
representation of the real world, we have to be able to "paste" small pieces of (flat) map
contents onto a curved world. The Geodetic Control is the mechanism that enables us to
perform this "pasting" seamlessly, accurately and consistently.
Traditionally, geodetic control points are established as permanent physical monuments
placed in the ground and precisely marked, located, and documented. Locating spatial
features with respect to geodetic control enables the accuracy assessment of these features.
Interest and activity regarding geodetic control has dramatically increased at all government
levels because of the need for accurate maps and surveys u
The proper design and optimization of geodetic networks is an integral part of most surveying
engineering projects. A geodetic network provides a framework for setting out the main
elements of a man-made structure (dams, bridges, power plants, tunnels, ports, etc.) and for
monitoring the position and deformation of these elements after the construction. They can
also be used to monitor crustal deformation. Networks, which are generally designed for a
limited and specific purpose, are called the local networks. On the other hand, there exist multi-
purpose networks—national control networks for instance—which play an important role when
preparing the coverage maps of the country. They are also called the reference networks, and
can also be used for geophysical, geological, and geodynamics studies in the national scale.
Typically, the design problem includes decisions on the number and position of the stations
and also on the selection of the observations and their precision.
The quality of a control geodetic network is characterized by its precision, reliability, and cost.
In other words, a network should be designed in such a way that:
− The prescribed precision of the network elements (e.g. coordinates or displacement of points)
can be realized,
− It becomes sensitive against statistical testing carried out for the detection of outliers in
measurements, and it resists against undetected gross errors,
− The construction of the points and the performance of the measurements satisfy some cost
criteria.
α c(cost)-1 +α r(reliability)+ αp (precision) ---------max
Where p α, r α, and c α are the weight coefficients for precision, reliability, and cost, respectively
Different optimization problems are usually classified into different orders as

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1. Zero-order-design (ZOD): design of a reference system (datum) for the network,
2. First-order-design (FOD): design of an optimal configuration for the network,
3. Second-order-design (SOD): optimal selection of the observables weights, and
4. Third-order-design (THOD): addition of observations to improve an existing network.
The first-order-design problem is to be understood as the configuration problem. For
example, one can select an optimal configuration to reach a network with high geometrical
strength (and hence of maximum reliability). The goal of this contribution is to optimize the
configuration of the network.
The second-order-design problem is the optimal selection of the weights of the
observations. For example, one can determine the precision of the observables to reach the
requested precision of the parameters of interest. Measures and criteria used for the precision
of a geodetic network are in general as 1) global precision criteria, 2) local precision criteria,
and 3) criterion matrices. Therefore, in the second-order-design problem one can choose the
covariance matrix of the observables such that the covariance matrix of the parameters is as
close as possible to an ideal covariance matrix (e.g. criterion matrix). Since the criterion used
in the second-order design problem is usually the ‘precision’ and not the ‘reliability’, further
discussion on this subject is beyond the scope of the present contribution.
The third order design problem is defined as the improvement of an existing network (or an
existing design) by insertion of additional points or observations. There are two methods that
can be used to solve the above design problems, namely the ‘trial and error’ method and the
‘analytical’ method. A primitive method suitable for FOD and SOD is the computer simulation
(or trial and error) method. The process is summarized in the following steps:
a. Specify precision and reliability criteria (e.g. error ellipses and redundancy numbers),
b. Select an observation scheme (stations, observations and their precision),
c. Compute the values of the quantities specified as precision and reliability criteria,
d. If the computed criteria are not close to those specified in (a), alter the observation scheme by
adding/removing the observations or by increasing /decreasing the weights of observations;
return to (c),
e. Compute the cost of the network and restart from (b) with a completely different scheme (e.g.
trilateration instead of triangulation). Stop when it is believed that the optimum (minimum cost)
network has been found.
Geodetic survey
To provide basic control data, the national geodetic network, consisting of first, second and
third order points, has been extended to cover an area of approximately 500 OOO.km. in
regions which have a relatively high potential in natural resources.
Extension and densification of the national control network is done on a continuous basis, at
an average rate of 30 000 km2 per year, using classical and GPS survey methods. However,

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some isolated areas are mapped using local control, depending on the application of the end
products. Geodetic control nets are also extended as required to regions where large-scale
mapping and engineering survey data are required. The control for these types of work are of
second and third order which is adequate for isolated surveys for irrigation, hydroelectric dam
construction, town planning and other related development schemes.
2.2 Benefit of geodetic network
Accurate Topography Maps
Topography (land surface elevation, also called terrain) provides an important,
basic component for many applications. Scientists use topographic maps to study
plants and animals, geology, hazards, and erosion.
Improved Floodplain and Inundation Maps
Floodplain maps are used to predict how water will flow on the Earth’s surface and
are crucial to assessing the risk of floods.
Uses of Real-Time Geodetic Positions
Accurate real-time locations are used in a wide range of commercial applications
and services. Accurate positions of Global Navigation Satellite System
(GNSS)/GPS satellites in their orbits and a terrestrial reference frame are used to
determine the location of an object on the surface of the Earth accurately.
Global Positioning System Monitoring and Improvement
The global geodetic infrastructure also contributes to improvements in the Global
Positioning System (GPS). For example, geodetic research has led directly to the
addition of a third GPS frequency and to the laser retroreflectors that may be added
to future GPS satellites.
Early Warning for Natural Hazards
For many centuries, humans have strived to provide warning of nature’s most
violent and hazardous events. Some of these events—earthquakes, volcanic
eruptions, and tsunamis—are caused by deformation of the Earth’s crust. Although
these events cannot be predicted beforehand, rapid detection of them can lead to
early warning and response. Even a few seconds of warning can allow people to
take action that can save lives and reduce the cost of an event.

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Figure 1 sketch illustrating the concept of earthquake early warning.
2.3 Network Formation
When creating a new network, it is important to try to find old points with both local and WGS84
coordinates, preferably surrounding the planned network to be able to relate the new points to
the old network system, if such exist, in the best possible way.
2.2.1 Triangulation
In "classical geodesy" (up to the sixties) control networks were established by triangulation
using measurements of angles and of some spare distances. The precise orientation to the
geographic north is achieved through methods of geodetic astronomy. The principal
instruments used are theodolites and tachometers, which nowadays are equipped with
infrared distance measuring, data bases, communication systems and partly by satellite links.
Figure 2 triangulation coordinate measurement source internet

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2.2.2 Trilateration
Electronic distance measurement (EDM) was introduced around 1960, when the prototype
instruments became small enough to be used in the field. Instead of using only sparse and
much less accurate distance measurements some control networks were established or
updated by using trilateration more accurate distance measurements than was previously
possible and no angle measurements. EDM increased network accuracies up to 1:1 million (1
cm per 10 km; today at least 10 times better) and made surveying less costly.
Figure 3 Trilateration coordinate measurement source internet
Global Navigation Satellite System, GNSS is a generic term for satellite systems for positioning
and navigation that today includes the American GPS and the Russian GLONASS system,
although there are several other systems under progress like the European GALILEO. All three
systems are compatible with each other. The first system accessible for public use was the
GPS system in 1983, five years later in 1988 GLONASS was also made available for civilians.
Today receivers are capable to collect data from both systems. When all three systems are
operable the total number of satellites will increase and that will contribute with significant
improvements in satellite availability, continuity and accuracy.

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2.2.3 GPS
GPS, Global Positioning System, is a satellite-based positioning and navigation system funded
and controlled by the U. S. Department of Defense and managed by United States Air Force
50 the Space Wing (Dana 2000). This initially was designed for military applications but today
is widely applied by civilian users in different fields, like in navigation, land surveying, different
mapping applications, research, and nowadays even as a hobby called
geocaching.(Establishing a Reference Network in Parts of Amhara Region, Ethiopia Using
Geodetic GPS Equipment, by- Anna Miskas and Andrea Molnar )
Figure 4 Satellite constellation GPS satellites orbiting with an inclination of 55˚ to the equator
(Establishing a Reference Network in Parts of Amhara Region, Ethiopia Using Geodetic GPS
Equipment, by- Anna Miskas and Andrea Molnar )
In 1993 the Initial Operational Capability level was reached and a final decision allowing civilian
use of GPS on the whole earth free of charges was made. Two years later when all the 24
satellites were activated Full Operational Capability was announced, this made applications
for military purpose possible.
The system today is based on at least 24 satellites orbiting the world at 20200 km altitude in
12 hours, in 6 different planes. This constellation with a 55 degree orbit inclination as seen in
Figure below provides a good coverage almost everywhere on the globe. For position
determination data must be collected from at least four satellites simultaneously, regardless
of the position on earth.
Figure 5-GPS monitoring stations around the equator and the main control station in Colorado

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2.3 Study Area
Geography
Ethiopia is located in northeast Africa, on the “Horn of Africa” and is occupying a significant
area, 1 230 000 square kilometers. The country is sharing frontiers with Eritrea and Djibouti in
the north and northeast, Kenya in the south and Sudan in the west.
Figure 6- Simple map of Ethiopia and neighboring countries.
Source: http://www.freewebs.com/vellache/Ethiopia.gif
Population
Ethiopia is the second most populated country in Africa with a population of 79 million, after
Nigeria, and the population growth is high. Four out of ten Ethiopians are under the age of 15.
Number of different ethnic groups and languages are unclear however the official number of
ethnic groups is 64. The two biggest groups are Oromo and Amhara followed by Tigray and
Somali. Historically the Amhara’s and Tigrays have been in power and Amharic is the official
language in Ethiopia. English is used in official contexts together with Amharic.
Climate
Ethiopia has a very dramatic topography with peaks reaching from over 4000 m down to
steppes and semi-deserts surrounding the Great Rift Valley all the way down to one of the
lowest areas in the whole of Africa, the Danakil depression. This great variation gives Ethiopia
extremely varied climate conditions, vegetation’s and settlement patterns.
Most of Ethiopia would have been in the tropical zone because its proximity to the equator but
since the majority of the country’s landmass is 1500 m above sea level the country is divided
into three climate zones.
• Cool Zone
Areas above 2400 m. Here average temperature ranges from near freezing to 16 degrees
Celsius.

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• Temperate Zone
Areas between 1500‐2400 m above sea level. Here the average temperature ranges
from 16‐30 degrees Celsius. This is where most of the population lives.
• Hot Zone
Areas below 1500 m, these areas have both tropical and arid conditions where average
temperature ranges from 27 degrees up to 41 degrees Celsius.
2.4 Geodetic network in Ethiopia
Ethiopian Mapping Authority, EMA, established 1954 is the official organization holding
surveying, mapping and remote sensing activities in Ethiopia. The existing national geodetic
network is composed of 1st , 2nd and 3rd order benchmark points covering an area of about
560 000 km 2 , including the majority of the areas of high potential in natural resources. The
greater part of the network was created using conventional triangulation traversing Points
made with this method dates more than 50 years back in time and have a poor accuracy,
compared to the accuracy that can be achieved with modern technology. Some parts
measured in more recent times were done using GPS methods. (EMA 2009).
(Establishing a Reference Network in Parts of Amhara Region, Ethiopia Using Geodetic
GPS Equipment, by- Anna Miskas and Andrea Molnar )

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3. Methodology
National geodetic network information from the national atlas of Ethiopia this paper will
show the process of generating spatial data, Meta data, and geodatabase and prepare
documentation regarding the overall procedure through which this document is prepared
by generating image and converting it to spatial data and adding the documents found
from the national atlas of Ethiopia to regarding national geodetic network to Arc Catalog
and digitizing all the information configuration of the Democratization of spatial data in
view of Cartographic.
3.1 Secondary data
Procedure for map production
• In the data entry we used the picture of National Geodetic Map taken by our camera
vertically from top, from the book, National Atlas of Ethiopia, Jan 1988, 1st edition.(p
64)
Figure 7– National geodetic network map taken from National Atlas map of Ethiopia
• Adindan As geodetic datum - for use in Eritrea; Ethiopia; South Sudan; Sudan.
Adindan references the Clarke 1880 (RGS) ellipsoid and the Greenwich prime
meridian. Adindan origin is Fundamental point: Station 15; Adindan. Latitude:
F
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22°10'07.110"N, longitude: 31°29'21.608"E (of Greenwich). Adindan is a geodetic
datum for Topographic mapping
• In the Geo-referencing process we used the picture taken and referenced it with a
map of Ethiopia, which is already referenced.
- To make accurate referencing, we have taken seventeen reference points.
After referencing, we rectify it.
Table – X - Y coordinates for Geo-referencing
Table 1. 1 - X, y coordinate for Geo referencing

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We convert it to KML and check the validation of the Geo-referenced map on Google
Earth.
• Digitizing
Creating personal Geo-database on catalog with class feature
Points – to locate the HIRAN Station fixed by ground survey.
Line – to show the network lines (HIRAN Trilateration line)
Polygon – to show the boundary of Ethiopia and its Regional Division
Figure 8 digitizing reference points

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• Populating the Meta data
In the Meta Data we entered the data we get from the National Atlas Map of
Ethiopia and fill in the catalog environment for the purpose of conveying non-
spatial data.
• Surface Data
We took the Slop, Contour, Aspect, View shed, Watershed and Stream features from
the Ethio-DEM
Process
The general procedures used for producing the maps are as follows: -
SURFACE ARC TOOLBOX SPATIAL ANALIST
TOOL
HYDROLOGY
The procedures are divided in to two groups in order to make it easy to understand.
1. Analysis From Surface
We have extracted the following, from the surface in spatial analyst tool.
- Aspect
Input - Ethio-DEM -
Contour
Input - Ethio-DEM -
Slope
Input – Ethio-DEM
- View shed
Input – Ethio-DEM
2. Analysis From Hydrology
We have extracted the following Stream features
- Fill
Input – Ethio-DEM
- Flow direction
Input - Fill
- Flow accumulation
Input – Flow direction
Arc toolbox – Spatial analyst tool -- Map Algebra -- Raster Calculator --- >500-
(A)
Arc toolbox – conversion tool --- from Raster ---- Raster to Polyline --- (B)
- Stream to feature
Input – Raster Calculated (A)
– Flow direction
- Stream link
Input – Raster to Polyline (B)

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– Flow direction
- Stream order
Input – Stream feature
– Flow Direction
- Basin
Personal Geo-Database --- Feature class --- Point --- (C)
Locating the junctions of big streams from our stream order map
- Snap Pour point
Input – Point (C)
– Flow accumulation
- Water shed
– Pour point

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4. Discussion and Result
After taking image and digitizing the map national geodetic network of Ethiopia, and all other
maps are generated by using Ethio DEM.
Figure 9– Hiran station fixed by Ground surve

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Figure 10– Trig/Hiran station

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Figure 11– Hiran Trilateration line

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Figure 12– overall network map

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4.1 Surface analysis
Surface analysis will depict surface conditions plotted from reported data or generated by
computer models. Surface analyst in GIS generated the contour, slope, aspect, and hill shade
maps. These topographic surfaces give us the effectively relate our data to real world elevation
and analyze how these varied surfaces will affect the data in question. By combining the terrain
maps with data in question a more realistic depiction of the area is presented which leads the
accurate analysis for issues such as the location of Ethiopia.

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4.1.1 Contour
Contour Lines are curves that connect points of equal elevation. Each contour line on a map
has a number that represents the elevation of the line, The Contour Interval is the change in
elevation between two contour lines. The slope map of Ethiopia is using 60 interval, and the
map shows the highest.
Figure 13– Contour Line Map

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4.1.2 View shed
A view shed is an area that is visible from a specific location. View shed analyses are a
common function of most geographic information system (GIS) software. The analysis uses
the elevation value of each cell of the digital elevation model (DEM) to determine visibility to
or from a particular cell. View shed identifies which cells in the DEM are visible from the
observer point, with a value of 1 indicating the cell is visible and 0 indicating it is not visible.
For the view shed we took our trilateration points as a view points to extract our view shed
from the Ethio-DEM.
We have taken two types of point
A. TRIG/HIRAN Station – View shed Map 1
B. HIRAN Station fixed by ground survey – View Shed Map 2

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Figure 14- view shade map 1

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Figure 15– view shade map 2

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4.1.3 Slope
Slope can be measured in degrees from horizontal (090), or percent slope (which is the rise
divided by the run, the slope of a TIN face is the steepest downhill slope of a plane defined by
the face.
Figure 16 – slope map (in %)

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4.1.4 Aspect
Aspect identifies the down slope direction of the maximum rate of change in value from each
cell to its neighbors. It can be thought of as the slope direction. The values of each cell in the
output raster indicate the compass direction that the surface faces at that location.
Figure 17– Aspect map

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4.2 Hydrology
The purpose of this exercise is to illustrate watershed and stream network delineation based
on digital elevation models using the Hydrology tools in the ArcGIS Geoprocessing toolbox.
The Hydrology tools are used to derive several data sets that collectively describe the drainage
patterns of the basin. Geoprocessing analysis is performed to recondition the digital elevation
model and generate data on flow direction, flow accumulation, streams link, stream network,
and watersheds. These data are then be used to develop a vector representation of
catchments and drainage lines from selected points that can then be used in network analysis.

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4.2.1 Flow Direction
One of the keys to deriving hydrologic characteristics of a surface is the ability to determine
the direction of flow from every cell in the raster. This is done with the Flow Direction tool.
Flow direction determines which direction water will flow in a given cell. Based on the
direction of the steepest descent in each cell, we measure flow direction.
Figure 18– Flow Direction

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4.2.2 Flow Accumulation
The Flow Accumulation shows the accumulated flow as the accumulated weight of all cells
flowing into each downslope cell. Cells with a high flow accumulation are areas of concentrated
flow and may be used to identify stream channels. Cells with a flow accumulation of 0 are local
topographic highs and may be used to identify ridges.
Figure 19– Flow Accumulation

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4.2.3 Stream to Feature
Stream to Feature Converts a raster representing a linear network to features representing the
linear network.
Figure 20– Stream Feature Map

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4.2.4 Stream Link
Stream Link function assigns unique values to sections of a raster linear network between
intersections. Links are the sections of a stream channel connecting two successive
junctions, a junction and the outlet, or a junction and the drainage divide. In hydrology, these
stream segments are called reaches. Links are the sections of a stream channel connecting
two successive junctions, a junction and the outlet, or a junction and the drainage divide.
Figure 21 - Stream Link

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4.2.5. Stream Order
Stream ordering is a method of assigning a numeric order to links in a stream network. This
order is a method for identifying and classifying types of streams based on their numbers of
tributaries.
Figure 22 – Stream Order Map

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4.2.6 Pour Point
Pour Point tool is used to ensure the selection of points of high accumulated flow when
delineating drainage basins using the Watershed tool. If the input pour point data is a point
feature class, it will be converted to a raster internally for processing.
Figure 23– Pour Point Location Map

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4.2.7 Water shed
Watershed is the upslope area that contributes flow—generally water—to a common outlet as
concentrated drainage. It can be part of a larger watershed and can also contain smaller
watersheds, called sub basins. The boundaries between watersheds are termed drainage
divides. The outlet, or pour point, is the point on the surface at which water flows out of an
area. It is the lowest point along the boundary of a watershed.
Figure 24– Water Shed Map

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4.2.8 Water Basin
The drainage basins are delineated within the analysis window by identifying ridge lines
between basins. The input flow direction raster is analyzed to find all sets of connected cells
that belong to the same drainage basin. The drainage basins are created by locating the pour
points at the edges of the analysis window (where water would pour out of the raster), as well
as sinks, then identifying the contributing area above each pour point.
Figure 25– Water Basin Ma

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5. Map revision
The old map taken as reference was published January 1988. it lacks some geographic
data of the existing Ethiopia. The old atlas map includes Eritrea as Ethiopian territory but
now Eritrea is no long Ethiopian land.
Ones again the 1988 atlas map divide Ethiopia with 14 regions. eriteriea Tigray, welo,
Gondar, Gojam, Welega, Shewa, Illubabor,Kefa,Gamo Gofa, Sidamo, Bale Harerge, Arsi
but now a days the regions are Amhara, Oromiya, Tigraye , SNN, Gambela, Afar,Somali,
Benshangule Gumz,Harare, and state Addis Abeba and Diredewa. Some regions
integrated as one region on the existing condition of Ethiopia.
6. Democratization
The project report and the result are democratized in order to address information about
geodetic network and their advantages for social, environmental value and economic
development of the country. We have used social medias to publicize the project like face
book, Instagram and link den with the title” DOCUMENTATION OF META DATA
MANAGEMENT IN CASE OF NATIONAL GEODETIC NETWORK MAP OF ETHIOPIA”.
.

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MAP OF ETHIOPIA
7. Conclusion
Geodetic control surveys are usually performed to establish a basic control network
(framework) from which supplemental surveying and mapping work.
These control networks consist of stable, identifiable points tied together by extremely
accurate observations. From these observations, datum values are computed and published.
These datum values provide the common basis that is so important to surveying and mapping
activities. Accurate network control may also be required for controlling interstate
transportation corridors (highways, pipelines, railroads, etc.); long-span bridge construction
alignment; geophysical studies; structural deformation monitoring of dams, buildings, and
similar facilities. In order to achieve all this task in appropriate location geodetic network play
a great role.
The result of the project, the new updated points, will hopefully be useful for the surveyor, map
makers, landscape architects and planners in their future fieldwork, since it is strained after
satisfying as many criteria as possible to relieve their work with easily accessible points. This
project tries to touch all the necessary criteria and details to generate the updated point by the
use of ARCGIS 10.4 and its features both spatial and hydrological analysis.
According to the aim of the project the points coordinates and all related information should
be available for everyone free of charge. We hope that various interested actors will benefit
from the existence of this network, serving as a useful tool for the future development in many
fields such as land administration, infrastructure projects etc.
geodetic network enables ground- and space-based observations that are critical to a wide
array of scientific disciplines, including seismology, geodynamics, climate science, hydrology,
oceanography, meteorology, and space weather. Geodetic observations, for example, allow
us to measure and monitor gradual changes in tectonic plate movement, sea level rise, glacial
ice melting, and aquifer depletion. Similarly, the geodetic infrastructure provides the foundation
for numerous applications with broad societal and commercial impact, from early warning
systems for hazards to intelligent transportation systems. In order to active, all this location of
the geodetic networking point, special analysis, hydrological and geological analysis are help
full.

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8. Recommendation
The first recommendation is to Ethiopian map authority to add as many as possible networking
datum throughout the country in order to have more accurate reference network for all country
development projects. and also mark and mount a fixed monument to the HIRAN points which
are on the arc map as a softcopy to assure a long lifetime for the network points, regular
maintenance program should be considered. For surveying in the future, the points of this
network can be used as reference points where an instrument is mounted on one of these as
a reference for the new station.
Refer the international geodetic services that are the main source of key parameters needed
to realize a stable global frame of reference, and to observe and study changes in the dynamic
Earth system.
Actively promote, sustain, improve and evolve the global geodetic infrastructure needed to
meet Earth science and societal requirements.
Recognize the benefits that GGOS provides to science and society as a core capability,
providing the fundamental underpinning of global Earth observations for monitoring of global
change, environment, natural hazards, etc.

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Reference
- National atlas of Ethiopia, January, 1988.1st edition
- (Establishing a Reference Network in Parts of Amhara Region, Ethiopia Using
Geodetic GPS Equipment, by- Anna Miskas and Andrea Molnar )
- Surface analysis using GIS Dr. M.V.S.S.Giridhar, Dr. G.K.Viswanadh and S.K.C.
Acharyulu
- ARCGIS 10.4 help manuals
- ANALYTICAL FIRST-ORDER-DESIGN OF GEODETIC NETWORKS A. R. Amiri-
Simkooei
- ON OPTIMISATION AND DESIGN OF GEODETIC NETWORKS Mohammad Amin
Alizadeh Khameneh
- Federal Geodetic Control Committee, 1984, Standards and Specifications for Geodetic
Control Networks: Silver Spring, Maryland, National Geodetic Survey, National Oceanic and
Atmospheric Administration, 29 p.
-

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