How to Get High Resolution Images from Google Earth
Update: Google Earth Pro is now available for free. You can export images up to 4800 x 2360 pixels, which is more than enough for most people. If you need higher than that, use the techniques below
This tutorial will show you high to create high resolution images from the free version of Google Earth. While Google Earth allows you to save a snapshot of the current view, the resolution of the resulting image is often not of a high enough quality to be used for detailed graphics or printed documents. The pro version does allow you to save images as large as 4800 x 3645 pixels, but by using this process, much larger resolution images can be created, some extra effort. The basic process involves taking many images in a gridded pattern, and then merging them together. For this tutorial, I’m going to be using downtown Boston as my location, and Photoshop as my image editing software of choice.
1. Open up Google Earth, and navigate to the area of interest.
2. Determine how big of an image you want (resolution), and over what area if should cover. It all depends on what the image is going to be used for.
In this example, I am going to use the image for a 24 inch wide printed document (18″ x 24″ sheet). Assuming that we follow the rule of 300 pixels an inch for print, our image would have to be at least 7200 pixels wide (24” x 300 pixels = 7200 pixels).
I’ve drawn a white rectangle outlining the general area I want to capture, which is shown below. This will serve as a guide in lining up our view. It’s not absolutely necessary, but it helps.
3. This next step involves saving the view from Earth. Figure out the resolution of your screen, and divide that by the total resolution of the desired image, to determine how many separate shots you need to take, and then merge them together. Having a higher resolution screen, and using multiple monitors if you have them, can reduce the overall number of shots needed to make up the final image (The Google Earth window can be pulled across multiple screens).
Example: My screen resolution is 1920 x 1080, minus a few pixels off the top for the menu bar. (maximize the window size by enabling full screen – in the view menu, turn off the navigation controls, and hide the sidebar)
7200 pixels / 1920 pixels = 3.75. This means we have to divide the area to be capture by at least 3.75 so that the final merged image will be of high enough quality. For simplicity sake, we’ll divide it by 4. In the image below, I drew 3 vertical lines to divide up the area by quarters.
4. Now zoom in until the top of the left column fills the screen, as you can see below. If you don’t have a mouse scroll wheel to zoom in and out, you may have to re-enable the navigation to get to the zoom controls.
5. Before we start saving the images, go into the tools menu, then options. Go to the terrain section under 3D view, and change the elevation exaggeration to .01. This is important because when moving the view around, the image edges will change perspective because of the 3D terrain, and they won’t line up easily with each other. After closing the option box, open the side panel back up, turn of the guidelines, close the panel, and then save an image of the current view (file > save > save image).
You now need to move the view over to the right to capture the next column. Make sure there is some overlap when you move the view around or else there will be no reference to line up the images. In the image below, you can see I’ve moved the view over to the next column, while still keeping the left guideline in view, so that there is some overlap between the two areas.
If you look to the right side of the image, you’ll notice that the next guideline is not in view (remember that I eye-balled them). When moving the view to the capture the next area, just make sure you remember where the last captured image ended, so that you can include some overlap between the two. You can also do this process without making any guidelines, but pay attention to how you move from one area to the next, so you don’t end up with any gaps. An easy trick to follow is by placing your mouse cursor in the top-right hand corner of the view, then clicking and dragging until the mouse is in the top-left hand corner of the view. This will minimize vertical movement, while allowing a small amount of overlap between each area.
6. After that row has been exported as images (it actually took me 5 shots to get the whole width), move down to the next row, and repeat. Keep in mind that the bottom of each image will have to be cropped to get rid of the Google Earth logo, so leave some extra overlap space between rows. The below image shows all of the Google Earth image saves in windows explorer. Notice that by naming them in a numerical fashion, and sizing the window correctly, you can see how all the images line up with each other.
7. Before we merge the images, the Google Earth logo has to be cropped off each one. If you have Photoshop, the easiest way to do this is by using an action (Tutorial Video from Youtube). If not, any image editor can be used to crop the images to get rid of the logo. Don’t forget to crop a few pixels off the top of each image, since there’s a small drop shadow at the top that is unwanted.
8. This step is where we merge the photos together, manually. I’ve tried different programs to do this automatically, but they never get it quite right, often skewing or warping some images, so the final merged image is distorted. Create a new document with a resolution of all of the images added together. 5 images wide x 1920 pixels = 9600 pixels, 5 images high x 950 pixels = 4750 pixels. I’m going to make the canvas 10,000 by 5,500 pixels to give some extra room. Now drag in the images one by one and line them up with their neighbors. Small adjustments of a few pixels up/down or left/right are necessary to match the edges of the photos exactly. The image below shows all 25 images positioned correctly, with the red lines showing the borders of each image. You can see from the edges of the photo that small shifts in each one were necessary to line them up correctly.
9. After some cropping, the image below will fit nicely on an 18 by 24 inch piece of paper. Of course it’s not any particular scale. Click to view at full resolution.
This technique can also be used for other image programs or web sites such as Google Maps or Bing Maps. Remember, that while you are able to zoom in as close to the ground as you like in Google Earth, there will be a point at which the satellite imagery starts to become blurry, and continuing to zoom in will not yield any image of a higher quality. Higher resolution images can sometimes be found at on local or state GIS sites, and can be downloaded by area.