Collecting X, Y coordinates for a location allows you to create a map or theme within ArcView GIS. The coordinates for a feature can be collected using several methods such as: a GPS receiver, a paper map, or ArcView itself. ArcView is capable of converting the coordinates of locations in the real world into features in an ArcView theme. The following steps show you how you can use collected coordinates to create a theme in ArcView.
1. Create the data using a spreadsheet or word processor such as Microsoft Excel and Microsoft Word. For this example we will be using Microsoft Word to create the data table that will be imported into ArcView. Enter the information for each record on a single line, using commas to separate the fields (characteristics). Use the Enter button to create a new line for each record.
The coordinate data includes two fields "Latitude" and "Longitude", which are attribute fields required to be created in the data table. Where other fields created, such as location or a landfill code, will be used as identifier fields so the coordinates locations can be unique from one another. The coordinates are most commonly measured as latitude and longitude in decimal degrees, so that is what will be used in this example. The field names for latitude and longitude will be either “Latitude” and “Longitude” or “Lat” and “Long” to keep it simple and it makes things run smoother in ArcView.
2. Next we will collect, and enter, the data into a Microsoft Word text file. For this example the coordinates collected are false locations of landfill sites throughout Nova Scotia. The Nova Scotia data for this exercise is taken from ESRI’s ArcCanada CD #1 in the ns data folder.
Open ArcView. Click on “Create a New Project: with a new View”, then click Yes in the pop up window that says “Would you like to add data to the View now?”.
Next, the following themes are to be selected from the ns folder included with the ArcCanada data: airports.shp, contours.shp, lakes.shp, lrgcity.shp, places.shp, provbnd.shp, rail.shp, rivers.shp, roads.shp, and utility.shp.
After all the themes are loaded into the View they can all be made visible by check marking the box next to the theme name.
* Note: Coordinates to the North and East are positive numbers and coordinates to the South and West are negative numbers.
Using the cursor, this step is repeated for the rest of the landfill sites throughout Nova Scotia. Fourteen landfill site coordinates are to be collected, and below is an example of text file that is to be created. The file was saved as Landfill_sites with a .txt file extension.
The top line is the name of the 4 attribute fields. Lf_Code and Location are fields that are used to better distinguish the sites by giving them unique attributes. Lat and Long are the fields that contain the latitude and logitude coordinates for each landfill site.
Bringing the Collected Coordinate Data into ArcView
3. Since ArcView is already open and a View has been already created with the desired ArcView themes, the next step is to add the data into an attribute table.
In the Project window, click the TABLES icon once, and then click the Add button at the top of the window.
This opens the Add Table window. Next, the Landfill_sites.txt file is selected as the table to add. This creates an new attribute table containing the fields and subsequent data that is contained in the Landfill_sites,txt file.
Creating a Map From the Coordinate Attribute Table
4. To map the data from this new attribute table an Event Theme has to be
created. The View to which the table will be mapped is opened and from the View menu the option Add Event Theme is chosen.
In the Add Event Theme window choose the table Landfill_sites.txt and select the proper fields to be used for the X-field (Long) and the Y-field (Lat). Click OK.
Now a new theme named Landfill_site.txt should appear in the legend of the View, on the left-hand side at the top. Click on the check box to make the theme visible. You should see all the locations of the landfills mapped in the View throughout Nova Scotia.
5. If you want to change the name of the theme to something more meaningful,
single click on the theme and then from the Theme menu select Properties…. In Theme Properties you can manually type in a new theme name such as “Landfill Sites”, or whatever theme name you desire.
6. You can change the symbol for the landfill locations if you wish by double
clicking on the Landfill Site theme in the View. This brings up the Legend Editor, where you can select any symbol by double clicking in the area of the current default symbol.
This pops up a Palette window that allows you to manually select any Fill, Pen, Marker, Font, or Color that you wish your landfill site symbol to appear as.
Your new Landfill Sites theme should resemble the final example below. This method of using X, Y coordinates for point locations can be used for many different applications. This was only one example using this method, but there are many other ways to implement these steps for creating new ArcView themes from coordinate data tables.