Tag: Shapefiles

A great open source tool for any GIS user

Before my time at the University of Richmond, the only mention of open source software was from computer science majors and programmers. Open source naturally seemed intimidating, since it was something new and mysterious, and in my mind sub-par to it’s proprietary counterpart. During my education, both universities I attended had a ESRI site license and rarely touched on open source GIS tools or software. The DSL has always leaned towards using open source software and its philosophy, which has been a great learning experience for me. I have begun to see the benefit in using both open source and proprietary software depending on the task.

While attending the VAMLIS conference last week, I attended a workshop presented by Jonah Adkins, a Sr. GIS Analyst for GISi. It was a great overview of open street map with some very useful open source tools on the web. Working with historical data, we tend to digitize a lot of polygons at the DSL. When serving these polygons up on the web it’s nice to generalize these for enhanced viewing optimization.  I have always had trouble simplifying polygons in Arc effectively and have dreaded this process every time I need to generalize a new data-set. Below is a great time saving tool for any GIS user struggling with simplifying polygons and wondering what tolerance levels to use.

When Jonah showed Mapshaper, “A tool for topologically aware shape simplification. Reads and writes Shapefile, GeoJSON and TopoJSON formats” tool at the conference, I was ecstatic! Not only can you upload a Shapefile, you can see in real time the simplification and the percent change from the original polygons.  It is one of the most simple, yet effective tools I have ever used. It is as simple as this.

1. Click on the link above. 

2. Configure your setting and upload file.

3. Slide simplify bar to simplify.

4. Export to Shapefile, GeoJSON and TopoJSON

5. Receive zipfile and enjoy simplify polygons.

6. Repeat!





So don’t be hesitant of open source options like I was. They can make your life a lot easier and broaden your knowledge while simplifying your workflows. Using a mix of proprietary and open source software/tools can be a powerful combination!




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