Ask A Cartographer

Deleting vertices

June 23 2011 | 0 comments
Categories: Map Data

Is there a way to tell Info to delete anomalous vertices?

So say you have GPS data where the user set the data to take one point per second, and they are driving on a dirt road going 10 MPH giving you 10K points plus on a mile long stretch.

You don’t need all those points and they are causing display problems for your roads. Can you give Info a set of instructions that will delete the majority of unnecessary points?

Mapping Center Answer:

I'm guessing there are really two issues here.  First is whether 10mph was just too slow, i.e., too many points in general.  The second is what to do about points on long straight sections, where additional vertices are not needed.

The Integrate tool will handle the first problem.  Warning--it works on the layer without creating a new layer, so make a copy to experiment on (I made several before finding an XY Tolerance that worked well for the data I was testing with.

The second problem is thornier.  Basically, the problem is to find straight subsections within line features, and then retain only the end points of those subsections.  It requires defining how long the shortest subsection to consider can be, and to not alter the curvy sections.  We don't have a tool for that, sorry.

 

If you would like to post a comment, please login.

Contact Us | Legal | Privacy |