Extended Abstract
Introduction
The new cities that have emerged with the aim of increasing the facilities and improving the quality of life and attracting the overflow population of the provinces, have not been able to provide the population they need and the people have not welcomed it because they have been unable to meet the needs of the residents. Therefore, it has become a place of dormitories and its urban spaces are empty of people during the day. Interactions, social trust in new cities are at low levels and its urban spaces are boring and monotonous. In general, it can be said that these spaces have not been able to meet the psychological and physical needs of the citizens. The purpose of this research is to explain the criteria of happy city in urban planning in Salmanshahr city in Mazandaran province. With the proper design of urban spaces, in addition to improving the quality of urban life, we can improve positive emotions in the environment and reduce negative emotions, thereby improving the interaction between the person and the place. For this purpose, in this research, the effectiveness of urban design dimensions (functional, visual, shape, etc.) in improving the positive emotions and satisfaction of citizens is investigated, and solutions are presented to improve people's happiness in Salmanshahr city.
 
Methodology
The current research is descriptive-analytical and based on library studies and field investigations in the form of a questionnaire. According to the subject of the research, the statistical population of this research includes all citizens who live in Salmanshahr city, which according to the census of 2015, the population of Salmanshahr city was 9656 people. Survey method and questionnaire technique are used to collect information related to the case sample. Due to the large size of the statistical population, the Cochran sampling method is used to collect the data. The appropriate size for the statistical sample was estimated to be around 384 people according to the Cochran formula. Finally, for more certainty, 400 questionnaires will be completed and included in the analysis. The sample members will be selected randomly according to the size of the investigated sub-communities (Salmanshahr city) and after collecting the desired questionnaire, the data will be analyzed using LIZREL statistical software and Sperm's correlation coefficient test and Kruskal-Wallis test were analyzed.
 
Results and Discussion
According to the review of the theoretical history of the research as well as the study of the theoretical foundations, the most important environmental variables that can affect the happiness of citizens were identified. These variables are: visual beautification of the city, access and transportation, housing, life and vitality, sense of security, social interactions, territorialism and sense of belonging, green space and nature, environmental health, tourism spaces, play and sports spaces, income and employment. which are divided into five general dimensions, visual, physical, socio-cultural, environmental, urban and economic services and facilities. Before dealing with the relationship between happiness and these variables, we will first analyze the status of these variables in the entire statistical sample and the studied areas to determine which region is in favorable condition and which one is in unfavorable condition. The data shows the average points obtained from the questionnaire for each index in the statistical sample, which shows that the variables of accessibility and transportation, visual beautification of the city, access to play and sports spaces, and income in the entire statistical sample are not in a favorable situation, and the rest of the variables are average. Their score is higher than the theoretical average of the data and they are in a relatively favorable situation. According to the results, among the urban areas, in areas five and one, all dimensions are at an average level and close to the theoretical mean (3). In area four, all dimensions except the visual-physical dimension are at an average level. In area three, Socio-cultural and economic dimensions are at a suitable level and in region two, only the score of the socio-cultural dimension is higher than the theoretical average. In the entire statistical sample, the visual and physical dimension and the dimension of urban services and facilities are not in a favorable situation with a score lower than the theoretical average.
 
 
Conclusion
According to the results of the Sperman correlation coefficient test, all research variables are related to the dependent variable of the research with a significance level of less than 0.05, and according to the value of the correlation coefficients, this relationship is positive. Among the research variables, employment, income, visual beautification of the city, access to green spaces, access to play spaces and tourism have the most relationship as dependent variables. And likewise, according to the results of the Kruskal-Wallis’s test, the investigated indicators have significant differences among the five areas of Salmanshahr city (p < 0.05). According to the results of this section, in terms of the selected indicators of Shad Shahr, the level of research indicators in different areas is not the same, which is similar to the results of the research of Akbari and Eltiam Nia (2021), Atashbar and Ilanlu (2021), Okulicz-Kozaryn (2017) is consistent.