Data Loading and Geocoding Part III: Using Coordinates

In our past two posts on geocoding in the data loader, we talked about how to correct incorrect addresses after loading points. But what do you do if you can’t get an address, or you can’t get the geocoder to find the address?


Let’s look at Saint Mary’s Hospital in Leonardtown, Maryland (with the big red circle below). In order to find where this is, we’ll have to use another online mapping system.

I know what you’re thinking – “There are other online mapping systems besides PolicyMap?” We were surprised, too. But it turns out websites like Google and Bing offer pretty good solutions to finding specific places in the world. PolicyMap is good at telling you about a place, with data. But since we don’t have an army of servers trawling the internet for everything that’s ever existed, we’re not always the best option for finding a specific establishment. So we’re going to use Google Maps to find Saint Mary’s Hospital.

In order to upload new latitude and longitude coordinates, you first need to download your partially geocoded dataset. You’ll then enter the new coordinates into the spreadsheet that already contains the old ones, and then re-upload the whole thing. Here are the steps:

1. Download the partially geocoded spreadsheet. Click on “Download Points” on the bottom of the page:


2. Open the downloaded spreadsheet. You’ll see the left two columns are called “X” and “Y”. These are your coordinates.

3. Go to the rows that don’t have numbers in the X and Y columns. Time to geocode.
One note about Google Maps: They recently changed their interface, and you may be using the old one or the new one. Both will work. I actually prefer the old interface, but the new works just as well.

According to Google, Saint Mary’s Hospital in Leonardtown, Maryland, is riiiiight here:


It doesn’t give an address, but it knows where it is. In order to show it on PolicyMap, you need to get the latitude and longitude coordinates. It might sound daunting, but it’s actually really easy.

Simply right-click on the point on the map, and click on “What’s here?” in the dropdown menu.


Once you click on it, the coordinates will appear near the search bar:


Note that they appear with the latitude first, followed by the longitude. Now, just copy each one into the spreadsheet, in the X and Y columns. Remember: in the continental United States, Y is always positive (because we’re above the equator) and X is always negative.

4. When you’re done entering your new coordinates, scroll to the bottom of the spreadsheet and delete the row that says “This dataset was created by [your name]. TRF’s PolicyMap does not endorse the use of or verify the accuracy of the data contained within this dataset.”

5. Save your spreadsheet. Make sure you save it as a .csv file, and not as a .xls file.

6. Go back to PolicyMap, and go to the data loader. It’s as if you’re loading a new dataset. Go to “Create a New Dataset” and “Upload Spreadsheet of Points”. Name the dataset, choose who you want to share it with, then load the csv.

7. Unlike last time, you’ll see that on the top right, it recognizes columns Y and X as “Latitude” and “Longitude”. Click on “Next” and you’re on your way.

It’s a lot of steps, but it’s not very difficult, and once you’re done, you have all your points on the map. Have any geocoding tips to share? Let us know, either by leaving a comment or sending us an e-mail.