For the time being most of the countries around the world trying to update their Urban Cadastral Map with the unified well known system this is the WGS84 UTM system. The coordinates systems in Iraq are divided into two systems: the first system was known as the "Third system" and the reference point located in AL-NAHRWAN south-east of Baghdad city and CLARK1880 was used, the second system was established terrestical topocentric coordinate system by "Pole Service Company "during 1979-1974,the reference point located in KARBALA ,and CLARK1880 UTM was used.
In our case study the Amana Baghdad Base Map having several coordinates systems which are not known specifically. In this research has been used an approach for the updating of the maps with WGS84 system regardless their original coordinates system to produce a photomap ; which would be considered as a base map and consisted of all characteristic of base map then use this base map as a reference map to update the Amana Baghdad base maps and produce an Urban Cadastral Map.
The study area was chosen in Baghdad city, Hay Al-Wahda, Mahala 906 including University of Technology Area. Database design will be done through using ArcGIS programme. A precision assessment of the updating approach for Urban Large Scale Cadastral Maps used in this research were done and founded the root mean square error is equal to ∓ 0.115 m ; which is complied within ASPRS standards.