topic Re: GENERALIZATION: I have a dataset on road polylines at a scale of 1:2500. What parameters can I use for a generalization to a smaller scale of 1:50000? in Mapping Questions

GENERALIZATION: I have a dataset on road polylines at a scale of 1:2500. What parameters can I use for a generalization to a smaller scale of 1:50000?

Paa_KwesiAkuffo_Ensaw — Mon, 18 Apr 2016 14:10:04 GMT

I am working on an assignment to automate generalization with the ArcGIS model builder.

I currently have a layer of road lines at a scale of 1:2500 with the intent to generalize to a smaller scale of 1:20000 and 1:50000

How can I justify the parameters for thin road network from a scale of 1:2500 to a small scale of 1:50000?

Secondly, what tools should i include in my workflow to automate my road polyline generalization?

Re: GENERALIZATION: I have a dataset on road polylines at a scale of 1:2500. What parameters can I use for a generalization to a smaller scale of 1:50000?

NeilAyres — Mon, 18 Apr 2016 14:18:39 GMT

Firstly, what version are you on?

These links from 10.3x help.

There is a whole bunch of tools in the cartography toolbox.

I don't think there are any hard and fast answers to your query. As usual, it will all depend on your data.

You will probably have to experiment, until you get some rules of thumb for your situation.

An overview of the Generalization toolset—Help | ArcGIS for Desktop

Understanding conflict resolution and generalization—Help | ArcGIS for Desktop

Automating conflict resolution and generalization workflows with geoprocessing—Help | ArcGIS for Desktop

Re: GENERALIZATION: I have a dataset on road polylines at a scale of 1:2500. What parameters can I use for a generalization to a smaller scale of 1:50000?

Paa_KwesiAkuffo_Ensaw — Mon, 18 Apr 2016 20:55:09 GMT

Thanks a lot Neil Ayres.

I am currently working in ArcGIS 10.3.

The data source was aerial imagery, digitized and georeferenced at 1:2500.

The generalization toolset has some truly very useful tools.I appreciate the samples of workflows using the model builder. But I'm still not confident about the various parameters used, for instance, the minimum length of roads to be thinned out using thin road network, the simplification tolerance value for simplifying polylines etc. At a different scale, how do I calculate these parameters?

Re: GENERALIZATION: I have a dataset on road polylines at a scale of 1:2500. What parameters can I use for a generalization to a smaller scale of 1:50000?

DanPatterson_Retired — Mon, 18 Apr 2016 21:25:02 GMT

I don't suppose you have an advanced license ...

Thin Road Network—Help | ArcGIS for Desktop

Collapse Road Detail—Help | ArcGIS for Desktop

or a standard or above license Simplify Line—Help | ArcGIS for Desktop

barring that everything would have to be a decision by you... for instance, you may choose to remove any roads that are less than 0.5 km in length... add a length field if you don't have one, query for those segments and (in edit mode), delete the features (in a copy of course). Or you could choose to delete crescents or roads that are not major highways. The automagic tools do require a higher licence.