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Thursday, 17 September 2015

200 million years of the dinosaurs life (sauropods) in a few seconds on the map

Free online geographic information system (GIS) called OpenWebGIS provides an opportunity to sample data from the Paleobiology Database (Paleontological database). This was described in detail in the article "The information tools(data base and GIS) to help paleontologists in their scientific researches". You can make your selections and apply them automatically on the map using the menu item of OpenWebGIS "GeoDataBase-> Paleobiology database".
OpenWebGIS has various functions to analyze these and other data. For example, users can create animated maps based on attribute with the date/time values. This is described in detail in this article: "Embedding animated maps of OpenWebGIS in your sites". Until the last moment, all the articles on OpenWebGIS stated that: "Dates/times in the field with date must be in format ISO8601: yyyy-mm-ddThh:mm:ss (for example:'2015-09-17T18:00:00'). It is necessary for animation in OpenWebGIS. "

It is well understandable. But how to animate your data if you do not have detailed information about the months, days, minutes, and, for example, there is only a list of years (1996, 1997, 1998 ... 2015)? Let`s assume it can be solved by adding to the data field with the years the following string ('-01-01T00: 00: 00'). But thus how to animate processes that lasted millions of years?

And in OpenWebGIS an enhanced version of "Time Line" function has appeared. Now, as a field containing the date the user can select any field containing "Numeric" data type.  Let's show how it works on the example of information about occurrence  Sauropods fossils selected from the Paleobiology database. Sauropods are an infraorder of saurischian ("lizard-hipped") dinosaurs.
Selection parameters  and the result on the map of selecting is shown in Figure 1. The points are colored according to the value of the "early_age" field (attribute). Early_age is the early bound of the geologic time range associated with this occurrence (in Ma (millions).
Figure 1

Further, we choose the name of the resulting layer "Sauropoda" in the list of "Editable Layer" and click on the menu item "View->Time Line", specify the parameters in the window as it is shown in Figure 2, then activate the option "heatmap". Learn how to create an animated heatmap, read here: Heatmap and Interpolation in OpenWebGIS (very easy and interestingly)
Figure 2

After setting all the desired parameters, click "Play" button and you will see what is shown in Figure 3, 4 and the video below. You will see how the distribution and the number of finds fossils of Sauropoda depending on early bound of the geologic time range associated with this occurrence. Millions of years will change in the window "Time Line" in red rectangles in Figure 3. We set the parameters of "Time Line" so that every 2 seconds time interval "early_age" is changed to 30 million years. Changing of the time comes from the later to the earlier fossils age (new), so we set the negative range (-30).
Figure 3
Figure 4


Ready interactive animated map with already established all necessary parameters, you can see at this link: Interactive MAP

We supplement the analysis of the animated map with the chart of the number of fossil discoveries according to their age. The chart is shown in Figure 5. The chart is created in OpenWebGIS using the menu item "Edit->Open attribute table"
Figure 5

From the map and chart it becomes clear that Sauropods first appeared in the late Triassic Period (about 228 million years ago, it is marked on the chart by an arrow with the number 1). The greatest diversity of sauropods reached in the Middle Jurassic period (174-157 million years ago) and Late Jurassic (Oxfordian), allowing many different types (marked by an arrow on the chart with the number 2). By the end of the Jurassic species diversity begins to decline slightly (indicated by the arrow on the chart with the number 3). At the beginning of the Cretaceous period (about 145-140 million years ago) Sauropods have inhabited the territory of almost all continents - Africa (Brachiosaurus), North America (Apatosaurus, Diplodocus), Europe (Xenoposeidon) and Asia (Qiaowanlong). In the Late Cretaceous period (93-66 million years ago, marked by an arrow on the chart with the number 4) there is a real surge (especially on the southern continent, where competition between ornithopods was minimal). The main variety in this period represents a group of titanosaurs. Conclusions about the species composition Sauropods can be drawn from the analysis of attribute table shown in Figure 6.

Figure 6

It is worth mentioning that in the results of selection from Paleobiology database turned out to be some records (in number of 47 from 2338) which "early_age" attribute was less than 21 million years. Although "late_age" (The late bound of the geologic time range associated with this occurrence) is in the range of 93-126 million years. It is known that according to the modern scientific opinion Sauropods became extinct about 66 million years ago. Therefore, these strange values "early_age" of 47 records may be explained by specialists paleontologists, or it is inaccurate and may simply be excluded from consideration. This article doesn't pretend on any scientific conclusion about dinosaurs. It only shows technical and analytical capabilities of OpenWebGIS
Paleobiology database has a powerful API and allows you to configure very subtly search the database, if you want to use OpenWebGIS for specify additional parameters of the selection from Paleobiology database, please contact us and we will do it, and add new opportunities to the interface.
Best regards, developers of OpenWebGIS.

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