Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I´m designing a geoprocessing service on ArcGIS Server using several nationwide datasets.

Currently I´m preparing some of the datasets and I´m wondering if I should dissolve my polygon layers (buffers) to have only one huge polygon with many, many vertices or if I would get better performance if I leave them with many small polygons (approx. 500.000).

The geoprocessing service will always be applied only on very small areas at a time.

share|improve this question
Your question is not clear? If you dissolve your polygon into one single polygon, you will lose data. For example, if you have a layer with state boundaries and you dissolve the state boundaries into one, then your state boundaries are lost. You will probably get a country boundary eventually. Right! So, there is no question of dissolving your polygon. Anyways, What map service you are using? If it is WMS, then considering map caching will improve your performance considerably. – thelastray Mar 19 '12 at 9:26
I´m buffering rivers to create datasets that show 5m, 10m distance zones. Using the buffer tool the resulting layer will consist of many polygons (one for each river element). I´m thinking about dissolving all the polygons in a single one. For me it doesn´t really matter if the distance zones are one or many polygons, so I want to choose the one with the better performance in a geoprocessing service. I´m not thinking about a map service like WMS in this case. My only interest is the geoprocessing. – Martin Mar 19 '12 at 10:39
up vote 5 down vote accepted

In most cases many small polygons + spatial index will be much better for performance than one huge polygon.

In case of one huge polygon actually you have no benefits from spatial indexing.

I have recently studied this question for my needs and from my opinion using many small polygons is highly prefered.

share|improve this answer
Thanks for your answer! My first thought would have been that one huge polygon is faster, since the file size is smaller. I´ll give it a try! – Martin Mar 19 '12 at 13:02

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.