The IF relies on the World of Science data and the Scimago relies on Scopus data. The IF is the number of citations in 2017 (for instance) divided by the number of publications in the former two years (2015 and 2016 in our case). The Scimago does the same but with three former years (2014, 2015, and 2016). The difference between the two measures is actually the data they use, that is, the World of Science is a more selective database, and the Scopus is more inclusive.
SJR (SCImago Journal Rank) indicator expresses the average number of weighted citations received in the selected year by the documents published in the selected journal in the three previous years, --i.e. weighted citations received in year X to documents published in the journal in years X-1, X-2 and X-3. The IF does the same measure but with a two years' window.
The IF relies on the World of Science data and the Scimago relies on Scopus data. The IF is the number of citations in 2017 (for instance) divided by the number of publications in the former two years (2015 and 2016 in our case). The Scimago does the same but with three former years (2014, 2015, and 2016). The difference between the two measures is actually the data they use, that is, the World of Science is a more selective database, and the Scopus is more inclusive.
The area of architecture does not have a category of its own in the World of Science, and there one could send an article to a related journal, such as Landscape and Urban planning. There are other architecture journals but they are not fully included in this database, such as Architect. You could try the Scopus database for more available journals.
In my opinion, IF and SJR are not the real descriptors to evaluate the quality of a journal. One should look for the domain of the journal. Publishing anywhere doesn't make any sense, irrespective of the high IF and SJR of the journal.
In my opinion one has to just look for real and fake journals for your research submission. Take care of your work by pre-workout for fake journals (many now a days) as theses journals show fake Impact factors SJR rankings on their websites, it will not only save your time and money but will also save your effort that you did in research.
IF belongs to the WOS and is calculated on the bases of: number of citations in a year/the total number of articles published during the 2 years before. The SJR belongs to Scopus and is calculated the same manner but divide on the 3 years before. IF is more tight that SJR. they might differ for the same journal.
More than 50 years ago, the ISI impact factor (IF) became the most important indicator of the quality of journals. Since 2007, the new SCImago Journal Rank Indicator (SJR) offers an alternative to the IF. SJR applies the Google algorithm (PageRank) to the journals of the SCOPUS bibliographic database that indexes more journals than ISI Web of Science.
SCImago Journal Rank (SJR) is a measure of the number of times an average paper in a particular journal is cited, and as such is conceptually similar to the Impact Factor. A major difference is that instead of each citation being counted as one, as with the Impact Factor, the SCImago Journal Rank assigns each citation a value greater or less than 1.00 based on the rank of the citing journal. The weighting is calculated using a three-year window of measurement and uses the Scopus database. Authors can use these metrics when deciding where to publish.
SCImago Journal Rank (SJR) is a measure of the number of times an average paper in a particular journal is cited, and as such is conceptually similar to the Impact Factor.
The SJR indicator provides an alternative to the impact factor (IF) or average citations per document in a 2-year period, abbreviated as "Cites per Doc. SJR is a measure of scientific influence of scholarly journals that accounts for both the number of citations received by a journal and the importance or prestige of the journals where such citations come from. To obtain the SJRQ indicator we divide the SJR by the number of articles published in the citation window.