Exploring Local
Mike Dobson of TeleMapics on Local Search and All Things Geospatial

Google Maps and Search – Just what is that red line showing?

April 24th, 2014 by admin

In an earlier blog in this series I contemplated a future sea-level change in online mapping that would develop as an adjunct to the popular mapping systems that are provided by Google, HERE, Bing, Apple and others. These database mapping systems currently are mainly oriented towards providing detailed street-level coverage, since this information meets the fundamental needs of users for geo-search and navigation.

Most mapping products are designed to meet the needs of map providers for generating income. For instance, HERE generates income by providing mapping databases and software that cater to the in-car navigation markets, as well as to ADAS, and other systems designed to make car travel safer and more efficient. Google, on the other hand, generates significant income by integrating its mapping activities into various aspects of its complex system of advertising. In addition, Google is obviously interested in other markets for spatial data, such as those focused on GIS and intelligent/autonomous cars.

All of the companies mentioned above, also, have users/customers interested in viewing maps that tell stories by showing aspects of geography or geographical aspects of a company’s services. For example, the American Airlines map that was shown in the original article in this series was an example of American Airlines attempting to show its global reach using online maps as the story telling device.

Recently, the online mapping providers mentioned above have begun attempting to increase the functionality of their mapping systems by providing data that allows the generation of “quasi-reference maps” whose objectives appear to be similar in approach to those formerly popular as printed world atlas products. It is my opinion that attempts to create a dual or multipurpose purpose production mapping system provisioned with the capability to publish both detailed street maps and world reference maps have been less than impressive. In part, this is due to these providers’ lack of familiarity with the intricacies of supporting the objectives, methods and presentational formats required to publish a wide range of mapping products from an integrated spatial database (e.g. street, reference and thematic maps).

In my opinion Google has made the most progress on dual-use maps and evidences a lot of promise for continued innovation. Even so, what they have created for us often does not make sense. Let’s look at one simple, fundamental object –geopolitical borders.

See the figures below for common examples of the complexity of harmonizing and generalizing multiple-purpose, multiple-source data bases. In these examples we can see that there are multiple representations of a feature in a database that has been designed to allow a variety of zoom levels. Each of the images was generated by typing a state or country name into the search bar that is a part of the Google Maps interface.

The targets of the searches are returned as a red outline and this appears to be true whether you are searching for countries, state, counties, cities or other categories of political or, where available, postal geography. These representations of boundaries symbolized in red first appear in a small scale representation encompassing the geography of the unit that was searched. Initially it appeared to me that each of these border representations disappeared at a preset zoom level that showed more map detail than the initial view, but the levels at which the boundaries symbolized in red disappeared (or at least segments of these borders disappeared) seemed to change both within and between classes of boundaries (e.g., international, state, county, city, etc.). Next. the levels at which the red lines on Google Maps disappear may be influenced by factors such as browser type and screen resolution, although I did not experiment specifically with these elements.

Let’s search for “Canada” as an example of using the place name search functionality in Google Maps.

Result of Canada Search on Google Maps

For a larger version of this image, click here

Yes, we are presented with a representation of Canada on which a red line demarcates a boundary.

Let’s search for the United States.

Results for a search for the US when using Google Maps

Hmm, no red border. Maybe this omission is a geolocation feature? If so, Google should note that a recent piece of research suggested that among Americans living in the US, some thought that the Ukraine was located within the US border. Perhaps showing the red border when someone searched for the U.S., similar to what is shown for other countries, might be useful. On the other hand, as we shall see, there is some question as to the nature of the “geography” that is actually being represented by the red outlines returned by Google and symbolized on their maps.

Look at the screenshots below and evaluate if any of these examples would inform someone who knew little geography and wanted to use Google maps as a reference source to help them understand the location of geographical borders.

Let’s replicate someone searching for the entity “California.”

California Search Result

To see a wider view, click here

What’s that dent in the northern border of California at Goose Lake? I didn’t know that Goose Lake was not part of California.

What specific border quality is that red line showing? If you look closely at the Goose Lake you can see a gray dash symbolized across the Lake that seems to follow the border between the two states as represented on official highway maps.

Let’s zoom in.


Hmm, guess I zoomed a little too much since the red line disappeared. However, what is shown appears to be one representation of the CA border that is similar to the one shown on the official state highway map. So what was that red line in the previous image?

Let’s zoom back out to bring back the red line.

Search and zoom out

It would appear that the red line, in this case, may demarcate the “land” boundary of California.

Let search for “Oregon” for support.

Oregon Search

Here Goose Lake is shown as excluded from Oregon by the red line.

Okay so it looks like the red line is not a standard political border, but the land-water boundary that follows the land side of the border of the entity named. Yep, searched for “California” again and Lake Tahoe was excluded by the red border. When I searched for “Nevada,” Lake Tahoe was not shown as part of NV.

Gee, that’s great, but where does Google tell the casual user the quality that the red line represents? In a page I found on Google Map legends the only reference to “red boundaries” was a note that “disputed” international borders were shown in red. However, I am not sure that the page I examined was authoritative, although it appeared on one of Google’s URLs. I doubt that the casual user would have any idea where to find out this sort of information. Indeed, I suspect that the casual user may, for example, search for California and conclude that Goose Lake, Lake Tahoe and various other water bodies are simply not part of California.

Oh, one other thing. It appears that the red boundaries are shown when zooming down to the level at which another feature takes precedence and replaces the red line. In essence, the occurrence of the representation of the red line is variable and tied to the local geography represented in the view port. For example, at the 20 mile zoom map the Oregon Boundary is still red.

Oregon boundary zoom

For a larger version, click here

But at the 10 mile zoom level the red is replaced by a gray dash that disappears when a more dominant feature in Google’s display hierarchy, such as a state or county road, is coincident with the border.

10 mile

For a larger version of this image, click here

This would seem to indicate that Google has implemented scale-variable presentation, a neat trick, but one that may make it difficult for the user searching for an entity and examining it at variable scales. However, when I searched fthe borders of a few more states, I ran into additional situations that further clouded the identity of Google’s red line.

Here is a good example. Let’s search for “Maryland.”


For a larger version, click here

Oh, my – Look at those straight segments of red line in Chesapeake Bay. I am not sure what representational logic applies here since the red line no longer appears to be demarcating the same “landed-ness” quality that it appeared to demarcate in the maps of California, Oregon or Nevada.

Let’s take a closer look.


Yowee! How does this red line relate to the others we have viewed?

If I look at Google Earth’s coverage of Maryland, at a similar scale, I see the same border in white. Hmmm, this is getting more confusing.

Maryland in Google Earth

Well, at this juncture I was thoroughly confused about the “identity” of the Google’s red line. I decided that I needed more data and returned to the start – Canada, one of my favorite places. So, I searched Google Maps for Canada, zoomed in, panned around, and found more interesting, but not reference quality data. Take a look at this –


For a larger version, click here

When I zoomed further most of the red border disappeared, but not all of it, a new red line behavior that I had not seen in our previous examples.


For a larger image, click here

How about that! What condition is the red line now representing? Hang on, it’s about to get stranger.

Even Stranger

To see a broader coverage extent, click here

I am not sure I understand anything about the red line now. In addition, I note that it does not appear to be coincident with some of the islands and other coastlines that it is supposed to follow. Who is editing this crap?

My head hurts

For a wider extent, click here

Look, more mismatches. Why the red line looks like it might be…oh DCW (Digital Chart of the World) or something similar. Anyway, maybe it’s just old, generalized data created from a spatial database designed for other circumstances. I guess this means that Google’s multiple representations of the same feature set have not been harmonized.

For a larger version, click here

Maybe the data on which the red line is based is so old that climate change has altered sea level or the extent of the icepack?
See this image

For a wider extent, click here

Well, regardless of the physical reality, it’s pretty sloppy representational work for an aspiring reference publisher.

I am sure that there is some reasonable explanation of the rationale for showing whatever it is that Google is showing with the red line. What the examples shown here point out is that it is difficult to compile a cartographic database and provision it with the diverse types of content needed to provide the range of data types and data elements required for presentation in a system that maps both detailed street data and more generalized regional or world reference information. It is, perhaps, even more difficult to harmonize (in terms of currentness and theme) and generalize these unique types of content when they are to be used in systems that provide output for numerous and wide-ranging map scales.

It is likely that all companies attempting this evolution from street map to reference map will run into numerous and substantive data quality problems. Two critical data quality issues that are clearly a problem for Google as evidenced by the above images are logical consistency (issues related to the correctness of the characteristics of a data set) and thematic accuracy (particularly in respect to non-quantitative attribute correctness and classification correctness). Unfortunately, this is just the tip of the data quality iceberg that Google and others are facing. It is the user and geographic literacy that suffer such attempts at experimentation.

From the perspective of the user, accepting the messages from these maps will depend on whether or not the spatial data is authoritative, coherently presented and understandable. We asked a simple and basic geography question and Google failed. For a company that has as a goal creating a perfect map of the world – well, they seem to have a very long road ahead.

As a final note, the question of revenue generation always is an issue with the production of maps. The red borders that Google shows may be as confusing as they appear to be because people who search for map borders of countries and states may not reflect the company’s financial interests in geolocation and navigation, which bring in lots of advertising revenue. Local borders are clearly more important. Why just look at this coherent border for Charleston, South Carolina.


For a larger version, click here

You may have noted that on some of the illustrations linked to above (the “larger” illustrations hidden unless you click the link) the search tab often contains a sub-tab labelled “terrain.” If you click the “terrain” tab in the live version of a Google Maps search, the system will show you a version of the map with terrain shading and the correct geopolitical border for the entity searched. If only the red lines that Google presents when you search for a geographic entity showed the same borders.

Well, it seems that Google needs help. Send your border info to “wherezit@.” It doesn’t matter where you send your data because Google or the NSA will be able to find it. Of course, this brings us back to authoritative data, trusted data and the whole conundrum we discussed years ago. It makes me feel good knowing that my blogs are “timeless”. Hah!

Duane Marble would prefer my blogs to be “Typo-less”, but I would miss his caustic notes containing edits, so no go.

Until next time,

Dr. Mike

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Posted in Apple, Authority and mapping, Bing maps, Categorization, Geospatial, Google, Google maps, HERE Maps, map compilation, map updating, Mapping, MapQuest, Microsoft, Mike Dobson, Navteq, Nokia, Technology

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