This paper presents the stages and the method for implementation of AM/FM system as well as the advantages and disadvantages of utilizing high-resolution satellite images and RTK survey for AM/FM systems with regard to the municipality

The main objectives of the project is to provide Riyadh Municipality with the results of the survey of manholes and gullies for ground and storm water in Riyadh City and the establishment of GIS database. The project was undertaken by Dar Al Taawon Consulting Eng. Spatial Information - GeoTech Group and completed in 6 months in 2002.

Objectives of the Study
The objectives of the municipality are briefly as follows:

• Automated mapping of the underground water and storm water facilities (gullies, manholes and pipes)
• Creating digital network information (data and maps) operated by computers
• Facility management system for these utilities
• Preparing reports, thematic maps, queries for any part of the system and following up the information of maintenance and operation
• Integrating this information with data such as roads etc.

The project area covers Riyadh Municipality boundaries, which consist of 16 Municipalities and 145 districts. The major task of the project is to survey of approximately

• 9638 manholes
• 17310 gullies

Each surveyed point will have a unique ID developed by the project, The surveying was carried out using Total Stations and GPS of static, fast static and kinematic (RTK). The field crews will be able to have cm-level precision by using the above-mentioned techniques.

Progress Of The Work
As mentioned above, the main objective of the project is to provide Riyadh Municipality an AM/FM System for Ground and Storm Water Facilities. The main purpose of this study is to provide the results of the survey of manholes and gullies for ground and storm water in Riyadh City and the establishment of GIS database. On October 28 / 2001 GPS Ground Control Points establishment started by 3 teams and went on at the rate of 40 points daily as an average and we completed approximately 2000 GPS Control Points.

There were 3 survey teams each team consists of 3 persons for surveying the manholes and catchbasin. The observations and data collection started on 14 November 2001. Surveying of all manholes and gullies were completed on 16 February 2002.

FIELD AND OFFICE WORKS CARRIED OUT IN THE PROJECT

RTK GPS Applications
Applications of the RTK surveys in Riyadh for storm water manholes and catchbasin are explained below.

1. At the beginning, some RTK tests were conducted to determine the range level of radios and achieved accuracy. Polygon points, which has been observed by fast static Differential GPS, to determine the difference between two systems coordinates to determine the locations of the points polygon ST28 has been determined as a base station. M412 polygons data, which has been located in 3 km radius from base station, has been taken with no signal loose in 3 second time period. This radius has been determine as maximum distance from the base station and continued to the observations in this range. Results of these polygons with two different systems have been shown in the Table 1, Figure 1.
2. Crew has started to observe the manholes to see the efficient of RTK system. All workday long 115 points have been observed by this system.
3. Crew has started to observe the manholes in Jazerah Region, which has not been any manhole observed before. A base station has been used, which has been determined and observed before. Quantity of manholes and catch basins that observed is 145 all workday long.
4. Fourth day of the test started at 7.00 AM and data for 230 manholes and catch basins has been collected.
5. Fifth day of the test a few loose signal has been detected because of long distance. And new base station has been determined and observed. Location of base station has been moved to its new location. Data for 170 manholes and catch basins has been collected.

The work in this area has continued for more than 4 days and totally 1241 manholes and catch basins and also 54 polygons observation by using RTK system.


Fig.1: View that shows the points which has been observed in two systems.

Fig.2: An example to daily work preparation on IKONOS Image and control points on IKONOS Image
Table 1: The difference of position data of the polygons that has been observed RTK and Fast Static GPS system

Crews had very efficiency product between 7.00 AM and 12.00 PM in the work. After 12.00 PM even some reduce in the quantity of the satellites as detected work has continued till 15.00. After this time period completely loose with the radio or satellite signals has been detected. Radio signal cut off have been detected when crew is 1 km away from the base station using 1Watt radio modem. Effect of the high buildings, trees, radio or TV towers, military areas has been detected.

Office Works and Field Survey
The study areas were determined using IKONOS image of Riyadh and the work areas were marked and plotted daily. The hardcopies of these images were also a guide for survey crews to locate the points. An example is shown is Fig. 2.

The collected data were transferred into a text document daily and saved with the survey date as a file name. The information about the surveyed points was transferred into drawings using a in-house developed application program and MS Access Database automatically using our application according to the text file and MS Access Database were linked to Microstation Geographics. All the as built plans of the utility were scanned and registered according to base map. These images were used only as a guide to locate the directions of the pipelines. Our office team digitized the pipelines using these images as a guide with a house made automatic mapping application tool. Some applications were developed for data linking, data editing and pipeline drawing. In the office team we were working with seven people to organize the system, prepare the working areas and proper information for survey crews, developing application programs and enter the data.

Mapping And GIS Implementation
The collected data was transferred in a text file daily. This file contain x, y, z coordinates for each point. Text files also contained code of each item.


Fig.3: Coding system for collected data
All text files were prepared daily using the collected data for each day by using x, y, z coordinates. We developed an application for creating these text files. The macro transfers x, y, z and ID from field survey equipment, finds the district for each point and wrote that in text file. The text file names were the date of the day, such as 10NOV01.txt for the collected data on 10 November 2001. Mapping was performed with a macro under MicroStation. Macro reads x, y coordinates for each item from text file and drew all points automatically on the locations which are read from text file. An example for automated mapping and menu items of the macro given in Figure 4. The GIS contains two different type of graphic feature. These are:

• Lines for pipelines
• Points for catch base, groundwater, manholes and storm water manholes.

Lines, which represent pipes, are drawn by snapping the points by a house made automatic mapping application tool. We developed a tool for digitizing the pipes. Operator combines two manholes according to registered as built maps using this tool. By clicking the manholes all the information such as x,y,z coordinates, municipality name, district code, street code, manhole number extracted and are transferred to the proper fields in the database representing beginning and end points of pipeline. After clicking the end point, the length of the pipeline measured automatically and is written in length field of the database.
The slope of the pipeline is calculated using the length of the segment and `z coordinates of beginning and end points - depth of manhole` information of the segment.

The database contains for point feature below mentioned items

• ID - was taken from field survey code
• X - was taken from field survey
• Y - was taken from field survey
• Z - was taken from field survey
• Street names - was taken from field survey code
• District names - was taken from field survey code
• Municipality names - was taken from field survey code
• Type of item - was taken from field survey code
• Type (normal or exit)
• Maintenance date
• Maintenance type
• Maintenance period
• Depth of manholes
• Diameter of manholes and line code
• Net name
• Contract numbers
• Contractor name

The database contains for line features below mentioned items.

• ID
• Code
• Maintenance period
• Maintenance type
• Maintenance date
• Type of pipe
• Length of pipe
• Slope of pipe
• Invert elevation
• Diameter of pipe
• Line code
• Net name
• Contract numbers
• Material
• Contractor name

These features are collected in Ms Access database. In house developed macro reads the code from text file and creates the fields in the database and put the information in the database automatically. These fields are

• Municipality names
• District names
• Street names
• Types of items
• ID for each item

An operator using another macro in micro station simply links the other features for the points. By using this macro, after clicking an item, a data entry dialog appears and operator can enter the data for each item.

These data will be linked in Ms Access automatically. The data may also be modified using this macro. The features that are entered by the operator are listed below:

• Maintenance date (date)
• Maintenance type (character)
• Maintenance period (character)
• Depth of manhole
• Type of manhole
• Diameter of the cover

All the ground and storm water maps compiled by Municipality were scanned. The Riyadh map and as built maps of municipality were registered and transformed by using the topographic maps that are compiled as part of project 116 of MOMRA and MOC roads, for digitizing of the pipelines. Pipelines were being digitized from these maps in MicroStation for the pipelines layer. These lines were guide for drawing line features of GIS. After creation of the line feature, user could link the data to the pipelines by using another macro. All the data that were linked by the operator were stored in Ms Access. The features, which were entered by operator, are listed below.

• Maintenance period
• Maintenance type
• Maintenance date
• Length of pipe
• Slope of pipe
• Type of pipe
• Diameter of pipe
• Type of facility
• Code of pipeline

The registered municipality maps were used as a guide for connecting the manholes with pipeline lines.

After creating all the graphic features and the data, the delivery was made in the Intergraph Geomedia 4 format. The Geomedia file was created with geocoding of the database.


Fig.4: In house developed application for creating data and data entering-updating
CONCLUSION
The establishment of graphical and non-graphical database constitutes the most significant part of any GIS application, as much as 90-95% of the total investment. It is wise to utilize space technology to establish geo-referenced digital graphical (mainly orthophoto maps) database with the consideration of the short time and low cost. Since applications like facility management go down to the level of individual structure/parcel corresponding a map scale of 1/1,000 to 1/5,000, the minimum requirement expected from urban imagery is:

• 1m. or a better resolution
• ortho-rectification to have map precision (e.g.: 1/1000 to 1/5,000), i.e to produce orthophoto maps (Eren et al 2002)

IKONOS will play a very significant role as many countries have an intense need for detailed, accurate satellite imagery for a multitude of important applications, such as mapping, agricultural monitoring, facility management and urban planning studies.