1 How to Re- project Coordinate Systems in ArcGIS . By: Tyler Gakstatter - Resource Supply, LLC. As a consultant, I frequently receive data from clients in a vari- ety of Coordinate Systems . It is not uncommon to have data in two or more Coordinate Systems for one project . While ArcMap can deal with this by re-projecting (for display only). data on-the-fly, it is imperative to have all data in the same co- ordinate system when using ArcPad. ArcPad, and many other GIS programs are not capable of re-projecting on the fly and will only allow data to be imported into the map if it matches the map's Coordinate system . The goal of this whitepaper is to describe the process of changing the Coordinate system of a data set to a different one. This can be done using ArcMap( ) with the project tool. We will go through the process step-by-step. The sample data that I will use was collected with an Ashtech Mobile Mapper 100 at a local city park.
2 The data was collected in the WGS 1984 geo- graphic Coordinate system . I want my data to be expressed in the UTM Zone 10 North coordi- nate system , and I will show you how to go about the conversion. Begin by opening ESRI ArcGIS and adding data into the map. My sample data is in the shapefile format and consists of points collected in the park with an Ashtech Mobile Mapper 100. I choose to collect the data in the common Coordinate system , Geographic World Geodetic system 1984(Geographic Coordinate system WGS84). Let's begin. 1. Click on the Add Layer icon with the black plus sign. 2. Navigate to the folder where your original data was saved. Select your original data file. In this ex- ample my data is in the ESRI Shapefile format. 3. Click Add. (Continued). Resource Supply, LLC. 11607 SW Winter Lake Drive Tigard, OR 97223. 503-521-0888. Jon's cell: 503-707-6236 Tyler's cell: 503-547-3756.
3 (Copyright 2014 by Resource Supply, LLC) 1. Now that the data is within the ArcGIS environment you can see that the map has been populat- ed with data points. There is also an entry in the Table of contents representing the data as a lay- er. Original data Before starting the process of re-projecting, it is a good idea to verify the Coordinate sys- tem of the original data. Do this by opening the layer properties with a right click on its entry in the Table of Contents and then click on Properties. (Continued). (Copyright 2014 by Resource Supply, LLC) 2. All of the information in the window is related to the original data set layer. For the purpose of this whitepaper we only care about the information under the Source tab. Now that I have verified that the Coordinate system is Geographic Cordinate system WGS84. (GCS_WGS_1984) the window can be closed and we can move on to the next step: Re- projecting.
4 The ArcGIS project Tool First of all lets clear something up, the project tool should really be called the Re- project tool. It can be confusing. The reason is the input data set MUST already have a projection before the project tool can do anything. The tool is designed to take a data set in one pr ojection and convert it to another projection, not define a Coordinate system for a non-referenced dataset. There is another tool for that. (Continued). (Copyright 2014 by Resource Supply, LLC) 3. The project tool is found in ArcToolbox. ArcToolbox is open by default on the right hand side of ArcGIS . If it is not visible, click on the tab for it below. Than navigate to Data Manage- ment Tools -> Projections and Transformations. ArcToolBox Double click on the project tool to launch it. (Continued). (Copyright 2014 by Resource Supply, LLC) 4. This is the project tool.
5 The fields marked by the green symbol are required. The tool requires a single input dataset, a name for the new re-projected dataset, and the desired Coordinate system . Input Dataset or Feature Class: You can use the drop down menu to select the original feature class from the Table of Contents or click the browse button to select a file stored on the file system . This feature class will be re-projected from it's original coordi- nate system to the new Coordinate system . Input Coordinate system : The input Coordinate system is automatically detected by the project tool. In this example the input Coordinate system is GCS_WGS_1984. Output Dataset or Feature Class: Name the new feature class file. The new file (in this case a shapefile) will contain the original feature class represented in the new Coordinate system . The project tool does not overwrite the original file.
6 When you name the file the project tool chooses the location by default. A different location can be specified (Recommended). Output Coordinate system : Choose the Coordinate system to re- project the original dataset into. In this example the original dataset is pro- jected in WGS84, and we want it to be projected in UTM Zone 10N. Therefore in this example the output Coordinate system is UTM Zone 10N. Geographic Transformation (optional). For basic use, ArcGIS will automatically pick the geographic transformation when required. (Continued). (Copyright 2014 by Resource Supply, LLC) 5. Input Dataset or Feature Class Select the dataset within the Table of Contents: Click on the down arrow to the right of the text field. A drop-down menu with a list of all the current datasets will be shown. Simply click on a dataset to choose. Select dataset by browsing your PC: Click on the folder icon to bring up a file explorer.
7 Navigate to the location of the dataset, select it, and click Add . (Continued). (Copyright 2014 by Resource Supply, LLC) 6. Output Dataset or Feature Class: Here we tell the project Tool where the new shapefile should be saved and what name to save the shapefile as. I like to save my re-projected shapefile within the same folder as my original shapefile. As you can see below, the default save location is in the C:\GIS\Shapefiles\ and the file name is OriginalParkPointsWGS84_Proj . Change the name to represent what makes the best sense to you. To specify a different name for shapefile to be created by the project Tool, one option is to change the last part of the default path to the desired name. In this case, my new shapefile is going to use the UTM. Coordinate system . I will name this file ParkPoints(NAD83 UTM 10) to clarify that this dataset is in the UTM Coordinate system .
8 (Continued). (Copyright 2014 by Resource Supply, LLC) 7. Output Coordinate system : This part of the project tool defines which Coordinate system to translate the original data to. In this case the original data is in WGS 1984 but I want the data to be in UTM Zone 10N. This is where the output Coordinate system , UTM ZONE 10N, is defined. Start by clicking on the browse tool to find UTM ZONE 10N in the Coordinate system selection menu. Coordinate system Selection Menu Locate the Coordinate system UTM is a projected co- ordinate system ; click on the plus sign to ex- pand the Projected Coordinate Systems . folder. Scroll down until you find UTM . And scroll down once more until you find NAD 1983 . (Continued). (Copyright 2014 by Resource Supply, LLC) 8. Locate the Coordinate system And scroll down a final time until you find NAD 1983 UTM. Zone 10N.
9 Click OK. Note: North zones are north of the equator. South zones are south of the equator. (Continued). (Copyright 2014 by Resource Supply, LLC) 9. 4. Verify inputs and run the project tool Click OK to run the project tool! The re-projected feature class will be saved in the directory specified un- der the Output Dataset or Feature Class text box in the project tool. Your original dataset is still available and untouched. If you have questions, please call me at (503) 547-3756. Resource Supply, LLC. 11607 SW Winter Lake Drive Tigard, OR 97223. 503-521-0888. Jon's cell: 503-707-6236 Tyler's cell: 503-547-3756. (Copyright 2014 by Resource Supply, LLC) 10.