Advanced Geospatial Analysis Skills: Review and Self-Assessment

Projections, Datums, and Spatial Reference Systems

The following Skill Drills use the knowledge you have learned in previous courses, including Geospatial Concepts (GSP 101) and Geographic Information Science (GSP 270). Therefore, the instructions do not contain many step-by-step details. You should refer to previous coursework if needed. Registered students may also post questions on the weekly Q&A Discussion Forum on the Canvas LMS.

Skill Drill: Acquire data from the Los Angeles GIS Data Portal

The Los Angeles County GIS Data Portal, maintained by the County of Los Angeles, is a website where you can download many different types of GIS datasets. The website includes instructional material on how to use the site, including text and videos. You should already be somewhat familiar with this website based on previous coursework. If you need a refresher, I recommend watching the instructional videos before you begin. Navigate to the Los Angeles County GIS Data Portal and use the keyword city boundaries to search for city polygons on the website. Locate a shapefile containing the city polygons and download the file. Decompress the file in your original folder.

An image of the Los Angeles County GIS Data Portal

In ArcMap, open a new blank map document add the layer to your Table of Contents. This layer will define the spatial reference for the dataframe window if it is the first layer loaded into the table of contents.

An image of the city polygon added to arcmapRepeat the steps for locating and downloading data from the Lost Angeles GIS Data Portal. This time use the keyword roads to find the 2010 TIGER roads layer. Download the data and add it to your map document Table of Contents.

An image of the Los Angeles GIS Data Portal.

In a separate document write down the answer to the following questions:

Question 01: What is the projection of the dataframe in the current map document (.mxd)?

Question 02: What is the datum of the dataframe in the current map document (.mxd)?

Question 03: What is the spatial reference system of the dataframe in the current map document (.mxd)?

Question 04: What is the projection of the Tiger Roads layer?

Question 05: What is the datum of the Tiger Roads layer?

Question 06: What is the spatial reference system of the Tiger Roads layer?

Question 07: If you wanted to create a Tiger Roads layer that used different spatial reference system, datum, and projection, which tool in ArcMap would you need to use?