Lab 9

Projection Conversion and Editing

Part 1

Begin by adding a few files that are in different projections - add the following data from Lab 9 Data

counties.shp (notice the units in the box at the bottom left) and

citybndstateplane.shp

Now click on the world icon to bring the screen to full extent. You should see both shapefiles at quite a distance from each other, not superimposed as you would want them to be. These shapefiles represent the cities within Salt Lake County. What you see on your screen happens often, though not as often now that we have the projection on the fly tool built in, that allows shapefiles in two different projections to be superimposed without any problem. Just remember, that the first shapefile you add to ArcMap, will set the units for the dataframe.

Now, again start a new window and add citybnd2.shp which is in State Plane and we will re-project from State Plane to UTM, NAD 1983.

To re-project a shapefile you:

Go into Toolbox

Data Management Tools

Projections and Transformations

Feature

Project

It will ask you to input the file you want to change the projection for. It will give you a default output name in the same directory, so you can change the name here. Next, specify the output coordinate system (UTM - NAD 1983 - Zone 12N). "Geographic Transformation" is the mathematical algorithm that transforms the projection. Select the transformation NAD_1927_To_NAD_1983_NADCON and click on OK. The way to check if the transformation was successful, is to open a new window and add the new shapefile, which will by default have project added to the name. (Remember to save it to your directory so you know where it resides). The correct units (meters) should appear in the lower right window.

Set up a map in Layout and add a title, your name and a scale bar. The units on the scale bar will say meters once you add it to the map. Print this up and hand it in. Label it as Lab 9 – Part 1.

Part 2

Add the following data to ArcMap:

murray.img

roads.shp

Make sure the image is on the bottom.

<>You are creating an updated road file for the City of Murray for this section of the city. Working with the data in the lower half of the image around the freeway loops, you need to update all new roads that appear on the image and are not part of the road file, and adjust the existing roads so that they correspond with what you see in the image. This will create a more accurate road file. For the freeway and on and off ramps, you need only have one line centered on the road. I will let you figure this one our on your own based on the tools and methods you learned early on in the semester. If you see any lines where there is not a road, delete it. You can clip all of the roads that overlap the image by creating a shapefile the size of the image and use that as your clip file. It will be easier to view the roads superimposed on the image, if you change the color to a yellow and make the width 2.

Set the map up in Layout with a north arrow, scale bar, title and your name. Label this map Lab 9 – Part 2.