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"Fair Use" And Google Earth Imagery

Published by
Leszek Pawlowicz
 in GIS and Google Earth. 7 Comments

I’ve gotten a few comments on my post about importing georeferenced Google Earth imagery into a GIS, talking about the legality of using the imagery in a business context, and pointing out restrictions contained in the Google Earth user license and the general Google Terms Of Service. While my post mentions that the restrictions of the Google Earth license and “fair use” need to be followed when using this imagery, at least one person equated the use of Google Earth imagery in this manner with theft, dismissing both the concept and legal precedents of “fair use”. So I’ll add some additional thoughts on when it’s appropriate to use Google Earth imagery, based both on a layman’s reading of the user license and the principles of “fair use”. I’d welcome further input from anyone who is an expert on issues of copyright and fair use, and also from anyone from Google who wants to give their take on the issue.

By the terms of the recent revision of the license, the Google Earth software can be use both for “personal, non-commercial uses according to these Terms of Service and the Software documentation“, and for businesses, “the Software may be used by you and your employees for internal use according to these Terms of Service and the Software documentation“. The software comes with the ability to export the satellite imagery on-screen, and the Google Earth API comes with the ability to provide the bounds of the onscreen image, so the actual act of creating an georeferenced Google Earth image is not a violation of either the license or the Digital Millennium Copyright Act. In addition, the license states that, “You agree not to use the Software for any bulk printing or downloading of imagery, data or other content“, indicating that limited printing, downloads of imagery and data are acceptable. The ability to create such imagery directly from the Google Earth application using its built-in print and export functions confirms this interpretation, else Google would not have included this functionality.

Addendum (9/18/07): I should add that any use of the imagery requires you to maintain the Google logo and all the copyright notices embedded in the exported image to maintain proper attribution for the source.

The real question of “fair use” here comes down to how the imagery is used. In the general Google Terms of Service, under the “Content in the Services” section, it says:

“You should be aware that Content presented to you as part of the Services, including but not limited to advertisements in the Services and sponsored Content within the Services may be protected by intellectual property rights which are owned by the sponsors or advertisers who provide that Content to Google (or by other persons or companies on their behalf). You may not modify, rent, lease, loan, sell, distribute or create derivative works based on this Content (either in whole or in part) unless you have been specifically told that you may do so by Google or by the owners of that Content, in a separate agreement.”

The restrictions in any such Terms Of Service don’t preempt the use of any material that falls within the bounds of “fair use”, as numerous court cases have determined. Unfortunately, those bounds can be hard to define. I highly recommend the Wikipedia article on fair use and its references for more information on the topic, especially if you’re not familiar with the concept of “fair use”, since some of its implications may surprise you. Generally speaking, copyrighted material like the Google Earth images may be usable by others without explicit permission of the content creators based on the answers to number of questions:

– What is the purpose or character of the use? Does it enrich the public by adding something new, or is it merely intended to supersede the original content for profit without adding value? The first falls under fair use, the second doesn’t. Works derivative of other copyrighted material have been ruled to fall within the bounds of “fair use” as long as they don’t supersede the original and provide added value, even when the derivative works are sold commercially.

– What is the nature of the copied work? Factual information can’t be copyrighted, but expressions of factual data can be. Even here, it’s not a hard restriction. The Zapruder Kennedy assassination film was copyrighted by Time Magazine, but when they sued the publishers of a book for publishing stills from the film, they lost; publication of this material was held to be in the greater public interest than upholding the copyright.

– Is the amount of copyrighted material used significant and substantial? Reproducing a copyrighted work in its entirety is illegal, as in the case of the of the open source Google Earth clone Gaia that planned to use Google Earth imagery, or MP3 music files. Reproducing limited excerpts of copyrighted material is allowable under fair use if appropriate for the context, e.g. the use of Google Earth screenshots found on many websites and blogs, or excerpts of MP3 files when used in music review.

– Does use of the copyrighted material significantly impact the work’s value? If you use the imagery to undercut the value of the original copyrighted material, that’s an issue; if you use it in a fashion that doesn’t, that may fall under the provisions of fair use. The classic case concerning this was the Sony Betamax case, where the Supreme Court ruled that videotaping copyrighted material didn’t have such a negative impact, and thus fell under the protection of “fair use”. And this was even despite the broadcaster’s argument that this technology could be used to break the copyright law. The Supremes ruled that if a technology had legal uses, it couldn’t be outlawed just because it might be used in an illegal fashion; you had to prove that its principal use was to foster illegal use of copyrighted material (that’s why Napster got shut down).

No answer to any one of these question precludes use of the material under fair use; conversely, you might think you have a reasonable “fair use” right under all four questions, but a court might disagree. The way I interpret these “fair use” factors relating to Google Earth imagery (and I’m not a copyright lawyer, so this is a layman’s opinion):

– Use of limited amounts of Google Earth imagery for personal or non-commercial GIS usage when not distributed publicly very likely falls within the bounds of “fair use”.

– Use of Google Earth imagery for personal or non-commercial use for public distribution would seem to fall under the rubric of “fair use” when it is of a limited nature, some transformative value is added (e.g. plotting additional data on top of it, or using it as a basis for further explanatory information), and when it doesn’t impact the value of the original imagery. So, for example, plotting shapefile data on top of a Google Earth image in a GIS, and then distributing the resulting image publicly, may fall within the bounds of fair use when it’s not done for profit. Creating a large-area, high-resolution georeferenced mosaic of just the imagery alone, and then posting it for download on your website, even if you don’t charge for it, will in all likelihood earn you a cease-and-desist letter from Google, and for good cause.

– The legality of internal use of Google Earth imagery in a GIS for commercial purposes conceivably could depend on the usage, but this is a gray area shading towards black. Talk to your legal department, and be prepared for them to legitimately say “no” to any such use.

– Public use of Google Earth imagery in commercial settings likely falls under “fair use” in some cases, e.g. screenshots of Google Earth imagery for illustrative or informative purposes on a website or blog that earns revenue from displaying ads. Google has acknowledged and featured the work of several blogs that exhibit such screenshots along with ads. Beyond that, though, the legality of public use of Google Earth imagery in a commercial setting will depend on the answers to the “fair use” question above, which lies within the domain of copyright law. My guess would be that more often than not it doesn’t qualify as “fair use”, and even if you think it does, it probably doesn’t. Talk to your lawyers. I might add that if you really want to use satellite imagery for public commercial purposes, you’d be better off looking at using Google Maps instead, since the license and TOS allow for some commercial use of essentially the same satellite imagery you’ll find in Google Earth.




Importing Google Earth Imagery Into A GIS

Published by
Leszek Pawlowicz
 in GIS, Google Earth and MapWindow. 18 Comments

This post has gotten a very strong reaction from many people, mostly negative. They say use of Google Earth imagery in the manner outlined here is inappropriate, an illegal violation of the Google Earth EULA/TOS. More specifically, words like “theft”, “stealing” and “dirty” have been used to describe this. I feel that this use of Google Earth imagery for personal and non-commercial uses falls under the guidelines of “fair use”, and I explain why here. “Fair use” is not theft. But I acknowledge that I could very well be wrong about this falling under the umbrella of “fair use” protection, in which case it would be illegal. I’d welcome opinions from those knowledgeable about the rights and limitations of “fair use”, and will pull the post if an expert on these issues says that using Google Earth imagery as described below doesn’t constitute “fair use”.

You can save the displayed view in Google Earth by using the File=> Save => Save Image command (Ctrl-Alt-S is the shortcut), which saves the contents of the view window as a JPG file. But in order to use this image in a GIS program, it has to be georeferenced, i.e. coordinates assigned to the pixels. There are free image georeferencing options out there, and I’ll cover some of those soon, but that’s not necessary in this case – there’s a simpler way to get the georeferencing data for an image exported from Google Earth.

You will need to have installed Google Earth (of course), the free GIS program MapWindow, and the Shape2Earth plugin for MapWindow. Shape2Earth’s main function is converting shapefiles to Google Earth KML files, and while the full version costs $29.95, it will work in unregistered demo mode for up to 500 shapefile vertices, and here for georeferencing Google Earth imagery.

1. Open Google Earth, and zoom in to the area of interest.

2. Double-click on the “N” in the compass at the upper right to orient north to the top of the screen. Also double-click on the “0 tilt” icon (the box with the “X” in it on the left in the tilt adjustor) to set the tilt angle to zero.

3. Open MapWindow; if you haven’t already activated the Shape2Earth plugin, do so from the plugins menu.

4. From the Shape2Earth menu in MapWindow, select “Get Image from GE”, and click on the “Capture Image” button. If you haven’t already oriented the image with north at the top and zero tilt, you will be prompted to do so.

5. Save the image with the desired name as a JPG file. This will save a black-and-white jpg image of the current view in the Google Earth window, along with a worldfile (*.jpgw) containing the georeferencing information.

6. Go back to Google Earth, and without moving or changing the view in any way, save the current view (File => Save => Save Image) with the same name and location as the image in step 5,. This overwrites the previous black-and-white image with a color one of exactly the same area.

You now have the Google Earth image with the georeferencing data contained in the worldfile (geographic coordinates, WGS84 datum), which most GIS programs can open and read successfully. If there’s a problem, try changing the extension of the worldfile from *.jpgw to *.jgw.

Limitations of this approach:

  • The view in Google Earth is orthographic, i.e. you’re looking at a sphere from above. For views that are zoomed to view a relatively small area, the area is essentially a flat plane, and the georeferenced image shouldn’t have a large deviation from the true coordinates. The larger the area covered, the greater the deviation between the true and georeferenced coordinates.
  • Coordinates in Google Earth can be off from the true coordinates even for small areas; see this post for more info. This process doesn’t correct for any such deviation.
  • Imagery in Google Earth is copyrighted, and using it for any other purpose than viewing in Google Earth falls under the restrictions of copyright law and fair use. In particular, you have to leave the Google logo and copyright notices unaltered to maintain proper attribution.



Embedding And Extracting Worldfiles With MicroDEM

Published by
Leszek Pawlowicz
 in GIS and MicroDEM. Closed

As described in a previous post, the TatukGIS Viewer has the ability to open image files along with their associated worldfiles, and then convert the image to a GeoTiff with the worldfile georeferencing data embedded it. It can also open a georeferenced image file like a GeoTiff or MRSid, and then save it in JPG, PNG, BMP or TIF formats while creating an associated worldfile. The two biggest drawbacks are that it stamps every exported image at the bottom with the message “Exported with the TatukGIS Viewer www.TatukGIS.com” in yellow-accented letters, and it can’t embed coordinate system and datum data in the GeoTiff (e.g. UTM, WGS84). MicroDEM can’t do everything that the TatukGIS viewer can, and isn’t as easy to use. But it has the ability to convert image files with worldfiles into GeoTiffs, and export image files with worldfiles, but without the stamped message at the bottom. It also has a limited ability to embed coordinate/datum data into the GeoTiffs along with the georeferencing data.

To convert an image file with a worldfile:

1. From the File=>Open menu, choose either “Open image” or “Open scanned map”

2. From the “Files of type” dropdown, choose “Imagery with world files”

3. Select the worldfile for the image you want to open (e.g. *.tfw, *.jgw, etc.)

4. The “Pick Projection Parameters” window will open. Here you can select the datum for the data, and the UTM zone for UTM coordinates. If the worldfile is in geographic coordinates (lat/long), the UTM Zone setting is irrelevant.

Capture8-14-2007-1.31.17 PM8-14-2007-10.47.04 PM9-11-2007-7.24.32 PM

5. Click OK, and the image will open onscreen, fully georeferenced. If you only want to export part of the image, you can select it with the subset and zoom button on the toolbar:

subsetandzoom

6. MicroDEM saves images in the screen resolution; to save in the full native resolution, you’ll have to zoom to 1:1; to do that, click on the “No zoom (1:1)” toolbar button:

zoom1to1

7. Choose File => Save map as image => GEOTIFF, screen scale. This will save the image as a GeoTiff, with the georeferencing data embedded, and with the coordinate system and WGS84 datum information also embedded. And no watermark stamp.

Limitations:

– JPG, BMP, GIF and PNG supported natively; MRSid is supported with add-ons, but isn’t easy to work with. Search the help file for “MRSid” for more info on how to set this up in MicroDEM.

– The only coordinate systems supported are geographic and UTM; no Lambert, SPCS, etc..

– The only datum data is exported in is WGS84, regardless of what datum the original data was in, and which datum you specified in step 4 above.

– GeoTiffs are exported in 24-bit color; 8-bit or indexed color is not supported.

If you want to go the other direction, converting a GeoTiff or MRSid file with embedded geodata into an image format with worldfile:

1. Open the GeoTiff/MRSid in MicroDEM

2. Select File => Save map as image => With worldfile

3. Select the desired image format (BMP, PNG or JPG), and save the file. The worldfile will be created automatically in the same directory.




Embedding And Extracting Worldfile Data With The TatukGIS Viewer

Published by
Leszek Pawlowicz
 in GIS. 2 Comments

Some image formats, like JPG and BMP, don’t support embedding of georeferencing data, so they require a worldfile to georeference them in GIS software. It can be inconvenient to move and keep track of two files instead of one, so it’s often useful to convert the original image into a format that supports embedded geodata, and then use the worldfile data to embed the appropriate georeferencing data into it. The TatukGIS Viewer is able to do that; it can open a raster image file in several different formats (JPG, BMP, PNG, TIF, ECW, SID, JP2), use the worldfile to georeference it, and then export it to the GeoTiff format with the georeferencing data embedded in it.

1. Open the image with the worldfile in the TatukGIS Viewer program (the Add Layer command)

2. Choose File => Export Image from the menu

3. Select Tag Image File Format (*.tif) as the desired export format, and enter the filename to save under

4. In the Export to TIF window that comes up, you can modify the bit depth of the image to reduce the colors/filesize of the image; you can also change the image size as well, and choose whether to export the whole image or just what’s visible on screen. TatukGIS will stamp a label on the bottom of the image, something to keep in mind when exporting part of the image.

Capture8-14-2007-1.31.17 PM8-14-2007-10.47.04 PM9-10-2007-9.13.07 PM

When you click the “Save” button, the image will be saved as a GeoTiff, with the coordinate georeferencing data embedded in it. Worldfiles don’t contain coordinate system or datum information, so that isn’t included in the georeferencing data embedded in the GeoTiff file. Also written is a *.tfw worldfile for the newly-created TIFF image, useful if the GIS program you’re using doesn’t read embedded GeoTiff coordinate data.

You can also go in the opposite direction: open an image file with embedded georeferencing data (e.g.GeoTiff, MRSid or ECW file), then convert it into a image format that doesn’t support embedded data (JPG, BMP and PNG), along with a worldfile that can used by other programs to georeference the image.

The TatukGIS Viewer is easy to use, flexible in export options like resolution and bit depth, and accepts a wide variety of raster images for export in georeferenced format. The biggest drawbacks are the label it stamps on the bottom of every exported image (which can be cropped off), and its inability to add coordinate system/datum information to the file. The next post in this series will talk about a program that’s less flexible and not quite as easy to use, but which doesn’t have a watermark, and has a limited ability to embed coordinate and datum information into the GeoTiff header.




Worldfile Basics

Published by
Leszek Pawlowicz
 in GIS. Closed

I’ll be doing a bunch of upcoming posts on free software for working with image worldfiles, so I thought I’d spend one post reviewing their basics. A worldfile is a simple text file that contains the information necessary to assign geographic coordinates to a raster image, to georeference it for use in a GIS program. For example, suppose I have a image like the one below (downsized by a factor of two from its original pixel dimensions of 1448 x 942 pixels):

Google Earth image with worldfile

The worldfile for the original image is:

0.000067897543
0.0000000
0.0000000
-0.0000554613012
-111.743323868834
35.1254392635083

The bottom two numbers are the longitude and latitude of the pixel in the upper-left-hand corner. The top number is the horizontal size of a pixel in coordinate units (longitude degrees in this case); the third number from the bottom is the comparable vertical pixel size in latitude degrees, negative because latitude decreases as you go from top to bottom in the image. The two other lines are rotation/compression factors for left/right and top/bottom, and are rarely used. Using the worldfile data, and the pixel dimensions of the image, a GIS can calculate the corresponding geographic position for every pixel in the image.

Worldfiles have an extension that depends on what kind of image file they’re associated with. Typically, it’s the first and last letters of the image extension, with a “w” at the end, but the full image extension with “w” at the end is also sometimes used. For example:

JPG image: worldfile has .jgw or jpgw extension.

BMP image: worldfile has .bpw or .bmpw

TIFF image: .tfw or .tifw

The extension .wld is supposedly acceptable as a general worldfile extension, but I’ve never seen it in the wild.

Worldfiles are plain text, and don’t contain any embedded information in them about the coordinate system. In the example above, it’s pretty obvious that the worldfile is in geographic coordinates, latitude/longitude. But the GIS program you open the image in won’t necessarily know that, and you’ll have to take care that the image’s coordinate system matches up with that of the other data you’re adding to the view. If your image is in geographic coordinates, and your shapefile data is in UTM, the GIS may not be able to convert the coordinates of them “on-the-fly” to match each other.

And there’s also the datum to keep in mind, since worldfiles don’t contain datum information, either. If the image is in the WGS84 datum, and your other data is in NAD27, there can be a distance discrepancy of hundreds of meters between the depicted position and the true position. Some programs can create another text file with the “.PRJ” extension that will contain information about the coordinate system and datum for a worldfile, but some free GIS programs can’t read that PRJ data.

Many image formats, like BMP and JPG, require a worldfile to georeference the image for use in a GIS. Other formats, like TIFF and MRSid, can use worldfiles, but can also have the georeferencing information embedded in the image file itself, optionally with coordinate system and datum information. For TIFF-format files, these are commonly referred to as GeoTiffs. Many GIS programs can open these files and extract the georeferencing data from them automatically, though a few can’t. And while you can open a GeoTiff file in an image editing program like Photoshop, if you save the image that georeferencing data is lost.

Upcoming posts in the series will deal with software that can do various things related to worldfiles, like:

– Combine a worldfile for an image format that doesn’t allow embedding coordinate data inside of it, and save it in a format that does support embedding;

– Extracting worldfile data from embedded coordinate data in an image, and re-embed it without modifying the image data

– Modifying an image file in Photoshop, and then re-embedding the coordinate data using a worldfile

– Creating worldfiles for map images that don’t have them, so that they can be used in a GIS

– Saving and embedding coordinate system / datum information in image formats that support it




Downloadable Cartograms From Worldmapper

Published by
Leszek Pawlowicz
 in cartography and data. Closed

A cartogram is a map where the area depicted depends on the value of a variable instead of the actual geographic size within the boundaries of the area. Worldmapper has a large collection of cartograms (366, with more added all the time). Here’s a cartogram of number of plant species by country:

271c

In addition to the graphic image, which can be downloaded by right-clicking on it and choosing “Save Image”, you can also download the data used to create the maps in Excel format and OpenDoc format. Some maps include animations of the map morphing from a standard map to a cartogram, and/or can be downloaded in PDF poster format (missing for some of the newer maps).

More info about cartograms is available at Cartogram Central.

Via BlinkGeo.




Geographically-Linked Video With VeoGeo

Published by
Leszek Pawlowicz
 in Google Maps. Closed

Javier writes (and Mapperz posts) about VeoGeo, a new website that lets you post videos, link them to a GPX file, and have the position where the video was taken be plotted in Google Maps. If your position changes during the video, the position plotted on the map will move as well. The process is fairly straightforward:

1. Register (for free) at VeoGeo. You’ll also need to be able to upload video files at any online site that allows embeddable video content (e.g. YouTube, Revver, MetaCafe, etc.)

2. Upload the GPX file to VeoGeo; this will have to be a continuous track file with the timestamps intact.

3. Upload the video file to the site of your choice, and copy the video link into the appropriate box at VeoGeo

4. Use VeoGeo to sync up the GPX track with the video.

You’re ready to go; the page for your “tour” will have the video window at upper-left, an altitude profile at lower left, and the Google Maps display at the right. Click on the video “play” button, and as the video plays, the marker on the map will reflect the position at the time the video was shot.

It’s a fun and clever concept, and has great promise for creating geographically-linked video tours. But there is some room for improvement:

– There’s no ability currently to edit the files to only show sections of a video; you have to upload (and watch) the whole thing. Most of the trips I take would have seconds of interesting footage interspersed with minutes (or hours) of boring footage of getting to that area.

– Initial Google Maps zoom level is too high; there’s no imagery initially visible on some pages. Zoom out a bit, and it should appear.

– There aren’t a large number of videos posted yet, but from the ones currently up, it’s clear that the most successful videos have the video shot with a camera firmly mounted so that there’s minimal shake. Walking and biking videos are less successful; without good image stabilization, they can be unwatchable for more than a short period of time.

– No help section yet (but they are in Beta)

– Small number of videos, so their current method of browsing for videos isn’t a problem (markers on a Google Map). But as the number of videos increases, they’re going to have to come up with a better browsing interface.

This site is a great match for Pict’Earth, and I hope the Pict’Earth people post some of their videos up on the VeoGeo site soon (hint, hint).




Geographic Time Animations

Published by
Leszek Pawlowicz
 in ESRI, GIS, Google Earth, KML and Web apps. Closed

While I was writing the previous post on xls2kml, which has the ability to add time data to point placemarks in a Google Earth KML file, I got an email from someone who was looking for ways to create time-animated geographic displays. Digging through my brain and bookmarks, I came up with the following:

– If you have ArcGIS 9.2, there’s a free extension called TimeSlider from Applied Science Associates that lets you animated multiple data series that have associated dates or times. Haven’t tried it myself (I’m still stuck with 8.2).

– TimeMap, from the University of Sydney’s Archaeological Computing Laboratory, creates time-based web mapping displays. From the “About” page:

“TimeMap TMJava is a novel mapping applet which generates complete interactive maps with a few simple lines of html. It provides a way of easily enriching web pages with historical or contemporary information that goes far beyond static jpg map images. It’s easy for beginners, yet provides completely customizable power and distributed backend database connectivity for the expert. It’s free for personal use.

TimeMap’s unique time-handling provides an engaging and intuitive method of delivering historical, community, government, research and business information. Combining mapping and the time dimension gives new ways of visualizing urban growth, the spread of empires, heritage sites, environmental change, weather patterns, traffic flow, earthquakes, mobile network faults, and much more ? ranging in time scale from millions of years to seconds.

TimeMap time-filters and animates maps on the fly, connects to datasets anywhere on the web and can search for and load thousands of local maps dynamically as you zoom and pan. TimeMap can filter huge datasets server-side and download only the data needed, or work standalone off a CD. It adapts legends dynamically as scale changes and generates hyperlinks on-the-fly between objects on the map and web pages, and is completely customizable with XML. Yet the applet weighs in at only 350K! ”

The TimeMap website has downloads, documentation, and sample applications. An open source version is on the way. Haven’t tried it this one yet either, but may post on it at greater depth in the future.

– Google Earth, of course, has added time-related coding to KML. But you still can’t add time information to data using the Google Earth application itself. Options for adding time coding are:

  • Add the time data manually to the KML file, as I did in my earlier sea level rise animations; this is currently the only option I know of for animating image overlays, and path/polygon KML files.
  • Use xls2kml to timecode point locations
  • Create a Google KML network link using Google Spreadsheets with timecoding added to point placemarks; Google has a tutorial page describing how to do this.
  • Create a KML network link to an EditGrid spreadsheet; OgleEarth has more info.
  • And I’m working on another way to create animated Google Earth KML files; more on this when it’s ready …

9/25/2007: Added info on EditGrid spreadsheets.




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