Creating Intersections for your source GIS

The recent posting on Intersection Creation from street segment data brought up another question from a user. Can you take the generated intersection features back to the source GIS? This is a very interesting question since GTIntersect and GTInterGtg were designed to generate the intersections for GTViewer’s use. Originally, the answer was no. While you could export the intersections to a DGN or Shapefiles or use FME to export the data to any other format, only the graphics would have been exported since the data was stored in a GTViewer tabular database. In the next version of GTData, GTIntersect and GTInterGtg have the ability to embed the tabular data on the intersection symbols, thus the export to Shapefiles or a .GTG conversion with FME will be able to export the tabular information as well as the graphics. GTData provides a variety of geoprocessing tools like the intersection generation utilities and more processes like this one will be discussed in future blog entries to help further enrich you source GIS data as well as the data used with GTViewer and its family of products.

Below, a few approaches to getting you intersection information back to your source GIS will be discuss.

If you want to take your generated intersections back to an ESRI system, the process will be like this:

1. Generate your intersections as before with GTIntersect or GTInterGtg, only add the EmbedData=1 option to the parameter file.
2. Import the Intersection .GTG file you create as Session Graphics in GTViewer (Draw/Import/Import GTViewer Graphics).
3. Export the Session Category data as a Shapefile (Draw/Export/Export As Shapefile)
4. You will get 3 files created in the specified Export Path: Inter_point.dbf, Inter_point.shp, Inter_point.shx
5. Use the generated files to update your ESRI system.

And alternative approach here would be to just use the GT2Shape utility (part of GTData) to directly convert the intersection .gtg file to shapefiles. This method would avoid using GTViewer and importing and exporting.

The process is a little different if you are using FME:

1. Generate your intersections as before with GTIntersect or GTInterGtg, only add the EmbedData=1 option to the parameter file.
2. In FME, select GTI_GTViewer as the source data type, then pick any format you want as the destination data type.
3. Then run the translation in FME.

The FME process is very straightforward and very flexible as to the type of output you want. It could convert to Geodatabase, Shapefiles, MapInfo, Smallworld, etc.; however, you must have FME and any required components to use this approach.