GIS technology to the masses

Greetings to all!

2 my articles were not very popular among readers, so I was silent and thought for a long time. So, probably the whole point is that the previous articles were rather narrowly specialized and aimed at understanding rather than the main audience. Therefore, this time I will try again to talk about GIS in fairly general terms, but using specific examples, thus showing the real possibilities of modern packages used in everyday tasks.


So, today we will talk about the most "mass" program, which, nevertheless, can demonstrate modern advances in satellite (including radar) photography, as well as the applied part of these "achievements".

This program - GlobalMapper - is distinguished by its small size and great functionality. Together with this program I will use, for example, the border taken from open sources of one of the reserves in Russia.
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When you start the program, we are greeted by an intuitive program interface, which is not frightening by the large number of menu sections or a bunch of obscure buttons:


I consider it right to immediately show the possibilities with an example, so I will open the prepared file of the boundaries of the Altai Reserve. It is important to note that in this example, the boundaries of the reserve are referenced by coordinates, which can be immediately observed by the coordinates of the mouse cursor appearing in the lower right corner:


Here, in general, and all that I will use in this example. It would seem that you can pull out of this boundary? It turns out a lot. Let's start with the fact that we download the picture on this territory. The GlobalMapper program uses open data sources, many of which I described in a previous article. In order to upload a snapshot to a given territory, we use the File -> Download Online Imagenery / Topo / Terrain Maps ... function available in the registered version of the program:


Depending on the connection speed, after a few seconds / minutes / hours, the selected image will be loaded onto your border (in the example, I chose Landsat 7 - Natural Color). The convenience of the initially attached file is that you don’t have to look for where the territory is, and you don’t have to upload any extra information - the snapshot will appear only within the visible area:


Now we no longer have just a border, but the border on the ground is what it looks like from the satellite. Immediately upload the relief here. We will do this through the same section of the menu by selecting SRTM Worldwide Elevation Data. SRTM - Shuttle Radar Topography Mission - satellite radar imagery with a resolution of 90 meters, limited to 60 latitude in the northern hemisphere and 54 - in the southern. Everything that is located beyond these latitudes is not represented in the SRTM database (in this case, you can use analogues, for example, GTopo). These radar surveys are loaded in the same way as simple images, in the end, after a certain time, we get the following picture:


We now have at our disposal both a snapshot of the territory and its orography. So, let's move on to the very interesting things that, I hope, will be appreciated by the audience that has no relation to GIS technologies. To begin with, we will review our territory in 3D - a snapshot will be strung to the data on the altitude of the terrain - we will get almost real perception of the terrain. To make the image “stretched” onto the orography, we change the order of the layers by clicking on the Open Control Center button and swap the 2 loaded layers by arrows:


All that is required of us now is to click the Show 3D View button in the toolbar:


After clicking, a new window will open in which we will see a three-dimensional image of the terrain:


In addition to the ability to fly over the terrain, there is also an option to see everything “through the eyes of a traveler” by clicking on binoculars. The buttons with up / down arrows and the image of the mountains allow you to increase or, respectively, reduce the vertical scale, making the relief more visual. The button with the image of water allows you to turn on the display of water at the zero mark, and the buttons with arrows next to it - raise or lower the water level . In this action is another practical application - it is a model of flooding the territory with certain natural phenomena (high floods and floods of rivers, tsunamis, prolonged rainfall, etc.)

And, finally, having seen enough of the relief in 3D mode, we will get the usual way of displaying heights from the school - horizontal . To do this, run the command File -> Generate Contours ... Having set the desired height of the cross-section of the relief and making the necessary settings, safely click OK:


Hiding all the extra layers, we got a set of contour lines for this territory:


Another, no less useful feature of this program is the ability to build profiles with the necessary data. We have this data (SRTM), so getting a ready profile on the right line is a matter of a few seconds. Using the 3D Path Profile / Line of Sight Tool - draw a profile with the left mouse button, finish with the right one. Immediately we get the elevation profile along the designated line:


Well, the last function considered in this article will be Overview from this point - a very important characteristic in recreational studies (overview / visibility of the area from this point) or, for example, to assess coverage of a cellular tower with a signal . To do this, select the Shed Tool and click in a specific place. After some thought, the program will produce a result by painting in red the areas viewed from this point:


I would like to remind you that all this was done with the presence of a single file with borders and an Internet connection for additional program functions.

This concludes this cognitive article. Thank you all for your attention!