Geographic Coordinate System & Projections

SUMMARY

Links: Introduction to Coordinate Systems

Time: The training took about two hours for me to complete.

Insights: This training gave me the opportunity to explore the ArcGIS application’s geographic coordinate system setup and projection capabilities. It was interesting to me to learn about and see the differences between the geographic coordinate systems and how those are projected in different ways. I didn’t realize there were so many ways to project data into a 2D plane, and I’m excited to become more familiar with when it’s most appropriate to use each different projection model.

Essential Vector Geoprocessing Tools

·        Define Projection vs Project: What is the difference between the ArcGIS Pro tools “Define Projection” and “Project?” Which tool do you use if the data are missing spatial reference? Which would you use if you want to transform data from a geographic to a projected coordinate system? Which tool overwrites a data set? Which creates a copy of the dataset?

 The Define Projection tool allows you to set or change the coordinate system for data if it has the wrong system or is missing a system altogether. It creates a copy of the data with the correct coordinate system.

Project is a tool that allows you to convert your data from one coordinate system to a different one. This tool overwrites the data set for a projected coordinate system.

·        Projecting a map vs Projecting Data: What is the difference between projecting a map and projecting data? Which one requires a tool? Which one changes how the map looks but leaves the data alone?

Projecting a map is the visual translation of map data from 3D to 2D. While this inevitably results in distortion in one form or another, the data of the map itself remains the same. Projecting Data requires a tool that calculates an aspect of the data depending on the information needed.

ESRI INTRODUCTION TO COORDINATE SYSTEMS TRAINING CERTIFICATION