Delete just a part of a picture

Hi everyone,

Background....

I am doing a project where I am trying to map out my local town.

So I am using screen shots to get the data, then joining these screenshots together.

Because I am limited to the number of photos I can add together I am having to do the town in sections, and then joining these sections together.

Set up....

I am using a iPad, and have the recent version of adobe express.

My question.

When joining these smaller maps together, because the screen shots are square, the edges don't follow the roads.

Is there a way to delete just a part of a picture?
Is there some sort of eraser tool that can be used to delete a section of the picture along a road and then join it to the next map along the same road?

Because I am manually having to resize each screenshot and join it together, there is a small margin of error and sometimes to sets of maps don't exactly join. But this discrepancy could be put into the road section of the maps rather than trying to do it through a housing estate! 

Can I delete up to the right hand side of a road on one map, and then join it to a photo that has had the left hand side of the same road deleted.

I can't seem to find anywhere on the app to do this. I can only delete entire screenshots, 

hope that all makes sense.

looking forward to a reply.