Hi, I have two boundary sets.
1. Census Enumeration Districts (EDs)
2. Polygons filling the space between the EDs and the official coastal boundary.
What I need to do is to extent the EDs to that coastline.
The job's 99% done, but some of the coastal slivers extend for several miles and as it stands, would be allocated to a single 'tadpole' ED. I need to break these slivers at ED boundaries.
What I am looking for is to:
Is this possible, please?
Many thanks
How many ED's and coastline polygons do you have that need fixing? Simplest manual way would be to append the coastline polygons into your ED layer, then use the split editing tool with snapping on to go along and split the coastline. Then select each pair and use the merge tool (making sure to select your ED polygon as the target the keep the attributes). Any automated solution will most likely introduce topology issues which you will have to go back and fix anyway. The question is then - how long will it take you do manually split\merge vs how long to find and fix the topology errors?
I don't think buffering will work, because it will have to find the exact buffer distance by trial and error to intersect the coastline at a single point (or 2 points with very small distance between them). As shown in your 4th slide, the computer can't tell that the buffer of the leftmost point is not correct.
Here's an alternative way, getting just the interior ED lines and using the Extend Lines tool to extend them to the coastline. Extra steps to export centroids to help turn them back into polygons at the end. Input are ED polygons (ED) and the original Coastline polygon (Coastline). Below are all the geoprocessing tool steps. I have attached some screenshots as well.
Now, this may not work if the last segments of your ED lines are at large angles to the coastline, if they are generally perpendicular to, or pointing at, the coastline then it should be ok. The most likely issue is that the extended lines cross each other, which you would have to go back and fix.