When building workflows in ArcGIS Pro ModelBuilder, it is common to repeat the same analysis several times. For example, you might want to run the IDW interpolation tool for multiple variables stored in a dataset. A simple approach would be to copy the IDW tool several times in your model and run it separately for… Continue reading
Post Category → Data
Getting Started with Tableau Prep: Preparing Data for Better Visualizations
Before building dashboards or creating visualizations in Tableau—or even preparing data for use in ArcGIS Pro—the data itself needs to be structured, clean, and ready for analysis. While some data preparation can be done directly in Tableau or ArcGIS Pro, Tableau Prep provides a dedicated environment for cleaning, combining, and shaping data before analysis begins…. Continue reading
Understanding Raster Operators in GIS: Local, Focal, Zonal, and Global Analysis
The language behind raster analysis Map algebra is a conceptual language designed specifically for cell-based geographic information systems. It provides the theoretical foundation for cartographic modeling, that is, using maps not just to display data, but to analyze and derive new spatial information. The idea of map algebra comes from work originally presented by Joe… Continue reading
Stack, Clip, Intersect! How GIS Overlay Analysis Turns Maps into Answers
The Power of Overlay: Making Maps Think for You Maps are great at showing us where things are, but GIS goes a step further by helping us understand how things relate to each other spatially. One of the most powerful ways GIS does this is through overlay analysis, a technique that works with both vector… Continue reading
What on Earth Are Thiessen Polygons and Why Should We Care?
If you’ve ever wondered how to split an area fairly without starting a territorial argument, Thiessen polygons (also called Voronoi polygons) are your new best friend. Think of them as the GIS equivalent of drawing invisible “zones of influence” around points, each polygon claiming the area closest to its point compared to any other.
My Message for Middle School Delegates at the Model UN in Boston
Closing the Gender Gap in STEM Careers, Improving Living Conditions in Informal Settlements and Urban Slums, The Situation in the DRC, and The State of Kosovar Independence.
Preparing Excel Tables for ArcGIS Pro
Working with GIS often starts with good data—and for many of us, that means working with Excel tables. Before importing your spreadsheets into ArcGIS Pro, it’s important to clean and format them properly. A little preparation upfront can save you a lot of time (and errors) later on. To make this easier, I’ve created a… Continue reading
Introduction to GIS Data: Choosing, Understanding, and Using It Responsibly
Choosing the Right Layers in GIS When you’re first exploring a data portal, it can be tempting to download and add every layer you see. After all, more data feels like more power, right? But in GIS, adding too much information can quickly lead to cluttered maps, longer processing times, and even misleading results.
Cartographic Principles, Classification and Symbology
Cartography is the art and science of making maps, and in the context of geographic information systems (GIS) it is a critical step in turning data into information people can actually use. Maps are not just pictures of geography—they are carefully designed tools that help us navigate, see patterns, understand relationships, and share knowledge about… Continue reading
Most Requested Geospatial Data
This site provides links to the most commonly requested geospatial datasets from some of the classes I teach. I also use some of this data myself, so in certain cases, I’ve included short videos to help guide you through data management or integrating the data into GIS.
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