Mapping the City

I live presently in the Dallas-Fort Worth metroplex of Texas, in the United States. There are some here who are interested in reaching out to diaspora peoples living in the city (a very large population).
We know there is a very large mix of nations here – Vietnamese, Arab, African, Latino, Chinese, Korean, more – but I have not yet encountered any kind of specific “map” of the area that would help guide strategic engagement by churches.
I’ve been thinking about how to do such a map in an easily reproduced way, that doesn’t involve either (a) huge numbers of grassroots workers, (b) complicated technology, websites or apps, or (c) expensive purchases of data. In short, what can a small team do, in any city?
One of the best simplest, best, easy-to-read, easy-to-implement chapters on mapping I’ve ever seen can be found in Tradecraft (and this is a great book for every church, really). It discusses the idea of paths (streets, trails, bus routes, subways, etc), nodes (centers of activity, strategic spots, squares, metro stations, etc), districts (areas of sameness, like neighborhoods, etc), edges (boundaries of districts), and landmarks. All of these can help us identify the subsets of cities.
My present idea is pretty simple. I’m going to take a map of DFW from Google Maps:
Then I’m going to zoom it a bit:
Now we have a grid. Is it possible to quickly move through this grid, looking at the “squares” outlined by the streets, and the nodes of the intersections, and the commercial areas, and ask – can we detect, simply by driveway, the larger groups in the area? Can we write a simple code (eg “vnm” for Vietnamese, etc) on a printed map? Identify mosques, temples, etc?
This would be a low-resolution map as a starting point, but might be enough to help us begin the process of engaging the diasporas here.
How would you improve on this process? Have you done something similar? Something better?