I want to increase the inbuilt txt size of a world street basemap layer.
How to increase a txt size of a basemap layer in ArcMap?
Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.Sign up to join this community
Essentially you can't. All of the formatting and display of basemap layers is pre-set by the basemap creator (in this case Esri). They've gone through and designed the layer to look a particular way at a given scale and you can't alter this. You could create your own annotations to sit on top of the map (using either the labeled or unlabeled version) that could be larger or more emphatic of the features you're trying to call attention to. You could also select a different basemap or create your own.
You can customize some properties of Esri Vector Basemaps (not just any basemap), including the labels font size.
These 3 steps are detailed in this blog post: How to Customize Esri Vector Basemaps, under Create a Custom Map.
To change the labels font size in the .json style file, you will nee to modify the
"text-size" property of some of the basemap's layers. This will require some fine-tuning but might be worth the effort if you plan to reuse your custom basemap.
Below you will find screenshots of the World Street Map vector basemap and a customized version with bigger labels: