Background

Coordinates system contain figure or numbers that help give reference to data and align them with other data and specific location while projection is the translation of a three dimensional object onto a flat surface such as a map or computer screen is referred to as projection. It is paramount to identify and understand coordinate system and projections of data in order to lay them in the right position for proper mapping and spatial analysis.

The aim of this lab is to acquire knowledge in the following areas:

• Learn about the differences between projected and un-projected map.
• Learn about the differences between geographical and projected coordinate system.
• Learn about assumed coordinate systems and how they can be used in site projects.
• Learn about reasons for data transformations from one coordinate system to another.
• Learn how to transform data to a desired coordinate system.

Methods

Task 1 Plotting Unprojected Data

The data on Columbia Habitat Monitoring Project was provided and this included an un-projected total station survey data and data from a handheld GPS unit for Bear Valley Creek Study Site. I downloaded the data, imported it into ArcMap and created a un-projected map. I included a measured grid overlay and provided a basic legend and labels. I emphasizing that the map was not spatially reference by putting a '?' close to the north pole and not including a basemap. click here for more detailed steps.

Task 2 Transforming Data

The aim of this task is to transform un-projected assumed Cartesian coordinate space to real world projected coordinates (NAD 83 UTM Zone 12 N).

I used the CHaMP Transformation Tool ArcGIS add-in to perform an affine transformation of the raw survey data around the benchmark survey points into the UTM coordinate system (Figure 1). Click here for more detailed instruction.

Task 3: Sharing Data with an Interactive Google Map

This is to provide a view for non-ArcGIS user. The projected map above was saved as a KMZ file and presented in alternative applications like Google map.

Results

The map below is the result of Task 1.

The map below is the result of Task 2

Interactive Google Map of Projected Bear Valley Creek is below

Summary

The results of this exercise showed that our data is correctly located and that the transformation into real world coordinates was successful.

Reference

Coordinate systems, projections, and transformations. http://desktop.arcgis.com/en/arcmap/10.3/guide-books/map-projections/about-geographic-coordinate-systems.htm. Retrieved on 24th January, 2017.

Joe Wheaton 2016, Lab 02 - Coordinate Data, Projections & Transformations. http://gis.joewheaton.org/assignments/labs/lab-02---coordinate-data-projections-transformations. Retrieved on 22th January, 2017.

Columbia Habitat Monitoring Program (CHaMP). https://www.champmonitoring.org/. Retrieved on 22th January, 2017

CHaMP Transformation Tool: An ArcGIS Add-In. http://ctt.joewheaton.org/home/download-tool. Retrieved on 22th January, 2017