Using GIS in Real Estate Transactions
by Dr. Abdulrahman H. Al-Husaini, CEO, Al Masfaq Company Limited, Riyadh, Kingdom of Saudi Arabia.
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INTRODUCTION:
The use of computerized information is a growing part of everyday life. More and more people are using geographic, social, economic, political and environmental information electronically to answer practical questions in their lives. The answers they find have relevance in their education, affect their business decisions, and influence personal choices expanding their understanding of the place they call home.
To explore their growing part of everyday life, people are using a range of electronic tools designed for acquiring, presenting and interacting with information. One of these is the Geographic Information System (GIS).
GIS is a tool that uses the power of the computer to pose and answer geographic questions by arranging and displaying data about places on the planet in a variety of ways, such as maps, charts, and tables. People have used maps for thousands of years to clearly present information about places, and GIS is a modern expansion of that ancient tradition.
What is Mretis?
- The AI-Masfaq Real Estate Trading Information System (Mretis) is a geographic information system application supporting real estate trading transactions. The application currently supports trading of real estate entities for the city of Riyadh, but has been designed to accommodate other cities in the future. The system uses and stores data in the Arcinfo Geographic Information System (GIS) software from (ESRI), USA. The system also uses the "Aljographi" Arabic language supplement for Arcinfo for its Arabic user interface and for the display/entry of Arabic text data and annotation. It also uses Oracle-7 for the storage and manipulation of real estate transactions data.
- Mretis facilitates a wide range of applications related to AI-Masfaq real estate trading requirements. Firstly, a real estate tradable landmark can be prepared and edited for the use by the system. Furthermore, the user can query the database for tradable landmarks meeting user specified criteria. Finally, reports, maps and logs can be produced, displayed and printed out.
- Mretis requires a graphical Unix-based workstation (Sun Spark 20 as a Server and 2 Sun Spark 5 as clients). It consists of a set of application programs built using Arc Macro Language (AML) that runs under Arcinfo GIS software. The Oracle Relational Database Management System (RDBMS) is used in conjunction to store and manage the real estate data. Transactions on Oracle database are performed through SQL statements embedded within application programs. Mretis, as a fully Arabized application, has implemented an Arabic geographical user interface in the form of menus, buttons, icons, check boxes and other graphical tools through the use of AIjographi Arabic language supplement to Arcinfo. So, Mretis users are able to enter, display, manage and get the appropriate output of geographic information without any need for issuing on-line commands.
- Mretis provides five basic modules:
1. Setting Real Estate Properties:
Manipulating real estate spatial properties and
classification information.
2. Registering Real Estate Entities for Trading; Marking
real estates for trading and setting attribute and
descriptive information, pricing, paying terms.. etc.
3. Searching for and Displaying of Tradable Real Estate
Entities; Querying the database for tradable landmarks that
meet user- defined criteria.
4. Displaying Data;
Going through the different districts for important
landmarks and streets.
5. Producing and Displaying of sketches, reports, log files
and images.
Mretis Source Data:
The source data for Mretis are hard copy plans of
Riyadh's districts from Riyadh Municipality as well as hard
copy maps of Riyadh's districts containing the results of a
citywide survey of landmarks (commercial centers, banks,
shops, pharmacies etc).
The data was entered by manual screen digitizing resulting
in the following:
- One Polygon coverage representing Riyadh general map and
containing district outlines, street closings and
annotations (main street names and square names).
- One Line coverage representing Riyadh general map and
containing central lines of main streets, border lines
between districts and annotations (main street names).
- 123 Polygon coverages of Riyadh district maps containing
block and parcel outlines, street closings and annotation
(major landmarks, district names and main street names).
- 123 Line coverages of Riyadh district maps containing
center lines of internal streets and annotations (internal
street names).
Mretis spatial database is maintained by Arcinfo while the
real estate trading database is maintained by Oracle.
The data stored in Oracle tables contain all the real estate
trading information as well as transactions. The Oracle
database consists of five main tables.
* Broker table:
(contains information about brokers houses registered as
AI-Masfaq clients).
* Customer table;
(contains information about customers registered with
AI-Masfaq).
* Parcel table;
(contains descriptive information about real estate entities
within districts of Riyadh).
* Building table:
(contains detailed information about buildings).
* Trans table:
(contains information related to trading transactions).
Brokers Solution:
The idea of AI-Masfaq was to connect the broker
houses with the real estate trading system through any kind
of networking communication. So the broker can access all
the data he needs through his office terminal.
But due to the insufficient communications and networking
facilities in Saudi Arabia (at this stage where the X-25
protocol is used), it was impossible to transfer such huge
amount of data, especially the graphical data, through the
available networking facilities.
The solution was a stand-alone PC unit and Arcview software
to minimize costs which will be very high if PC Arcinfo is
used. The challenge was to design an Arabized application an
that performs nearly all the tasks performed by Mretis.
The data (500 Megabyte) was transferred from Unix
workstation to the PC through PC NFS (Network Filing
System).
The main problem that we faced was the Arabization of
Arcview. Arabview, which is the Arabic supplement to
Arcview, allows both Arabic and Latin within Arcview. It can
perform the following:
- write Arabic text on maps,
- input Arabic data in any dialogue box,
- auto-label Arabic data,
- Arabic field titles,
- Arabic layout printing.
When it comes to databases, Arabview allows the
following:
- input Arabic data with the Arabic code of any
choice,
- access data from different Arabic databases,
- convert data from one code page to another.
We were the first company to buy Arabview in Saudi
Arabia and the first to design an Arabized application on
Arcview. To develop this application, 'Avenue', which is the
customization and development environment for Arcview Ver.2,
was used. It is an object oriented programming language that
allows to customize almost every aspect of Arcview.
An application in Arcview is referred to as a project. The project name is "AVMretis". It has five main components:
1. Views: which defines the geographic data. It is actually a collection of themes; every theme represents a distinct, set of geographic features in a particular geographic data source. In AVMretis, themes represent the following sources of geographic data:
- spatial data source which is the Arcinfo coverages of Riyadh districts.
- image data source which is photos of tradable real estate entities.
2. Tables: dbf tables transferred from Oracle database. In Arcview, tables refer to the tabular data source it represents; which means that these tables are dynamic because they reflect the current status of the source data they are based on.
3. Charts: It is a graphic representation of tabular data that provides a powerful visual representation of the attributes associates with geographic features. In our application, charts are used to compare between prices of real estates in different districts, display statistical numbers showing market trends of different real estate entities etc.
4. Layouts : It is a map that displays views, charts, tables, imported graphics and graphic primitives, and prepare these graphics for output from Arcview. A layout is dynamic as it allows to make specific graphics live; so if the data in a view changes, the layout automatically reflect the change.
In AVMretis, we have 5 layouts that are used as templates to produce standard maps and reports.
5. Scripts: It contains the avenue code that automate tasks, add new capabilities to Arcview and build the complete application.
In addition to the above components, multimedia functions were associated with the different modules of the application such as searching for and displaying of tradable real estate entities in which a voice describing the real estate entity (for example, a villa) and a scanned photo of it; as well as, a plan are displayed beside its geographic location on the map.
The system was established in the brokers houses in order to facilitate transaction.
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