Because the weather is very hot in the summer, people want shady spaces to get rid of the sun's overwhelming effect. In order to keep the buildings or the open-air environment in the shade, the buildings or rest areas to be constructed can be designed accordingly in the planning phase. The distance between the buildings, height of buildings, geodetic location of building, the time of day, the solar equalization angle at that time, the solar azimuth angle and the solar zenith angle are effective to the position of the shadow buildings on a reconstruction island at various times of the day. Separate or block arrangement is applied for the buildings to be built in the settlement areas. In practice, although there are special software, software prepared for the shadow effect of a building, but how the shadow of a building is calculated, and this research has been deemed necessary since there is not enough information about the effect of the shadow formed on neighboring buildings. In this study, in various district angle values and sun azimuth angle of a development island facade in Trakya region; the location of the shadow building on the neighboring garden area, backyard area and on a reconstruction island and on the facade of the building in the neighboring parcel were investigated. At the end of the study, suggestions were given about what should be done in order to ensure maximum shadowing on a development island while preparing the development plans.