[color=#999999]This activity belongs to the [i]GeoGebra book[/i] [url=https://www.geogebra.org/m/sw2cat9w]GeoGebra Principia[/url].[/color][br][br][br][center][b][color=#CC3300][size=200]VERSATILITY: List of Polylines[/size][/color][/b][/center]Lists allow a large amount of information to be grouped into [b]a single object[/b]. In this example, humble polygonal lines, lacking the elegance found in many curves, make up for it with the versatility that their grouping in a single list provides.[br][br]We can import large amounts of data into a [b]spreadsheet[/b]. In this case, 6122 geographical coordinates from publicly available North American Cartographic Information Society data [url=https://www.naturalearthdata.com/][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url], once cleaned up in a word processor and properly grouped, become lists.

Each point list is called by the [b]Polyline [/b]command, so we finally obtain a list of polygonal chains whose arguments are point lists. [b]Unlike polygons, let's remember that the vertices of the polyline don't necessarily have to lie in the same plane. [/b]Through this process, we achieve a singular design: that of the Earth's coastlines. Thanks to this design, we transform an ordinary sphere into a model of the Earth's surface.[br][list][*]Coast = {Polyline((5; 3.142; 1.204), (5; 3.117; 1.211), (5; 3.067; 1.22), (5; 3.031; 1.219), (5; 2.975; 1.223), (5; 2.967; 1.216), (5; 2.981; 1.204), (5; 2.96; 1.199), (5; 2.93; 1.214), (5; 2.896; 1.212), (5; 2.863; 1.216), (5; 2.832; 1.215), (5; 2.809; 1.212), (5; 2.787; 1.217), (5; 2.79; 1.23), (5; 2.775; 1.237), (5; 2.74; 1.24), (5; 2.67; 1.236), (5; 2.624; 1.25), (5; 2.609; 1.26), (5; 2.452; 1.271), (5; 2.429; 1.264), (5; 2.441; 1.248), (5; 2.413; 1.25), (5; 2.4; 1.245), (5; 2.366; 1.251), (5; 2.336; 1.246), (5; 2.308; 1.254), (5; 2.291; 1.236), (5; 2.264; 1.242), (5; 2.242; 1.256), (5; 2.252; 1.264), (5; 2.244; 1.275), ...[br][/*][/list]With this model [[url=https://www.geogebra.org/m/sw2cat9w#material/er8nf4qt]16[/url]] we can construct a scenario in which we can engage in a multitude of activities. These activities range from observing geographical elements (pole, meridian, parallel, cardinal point, equator, tropic, polar circle, time zone...), to conducting analysis and measurements (octant, latitude, longitude, course, rhumb line, orthodromic distances, spherical triangle...).[br][br][color=#999999]Note: This model can serve as an excellent example of the collaborative spirit that characterizes the resources created by the GeoGebra community since its inception. Using it as a template, Chris Cambré published books on GeoGebra about map projections [url=https://www.geogebra.org/m/dsbbxbwe][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url] in Dutch and English, as well as another one about Mercator [url=https://www.geogebra.org/m/yjxp7xm3][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url]. Afterwards, Carmen Mathias translated both into Portuguese ([url=https://www.geogebra.org/m/btfr5zww][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url], [url=https://www.geogebra.org/m/t2vhjamz][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url]). Closing the circle, I translated them into Spanish ([url=https://www.geogebra.org/m/xp33qgxu][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url], [url=https://www.geogebra.org/m/ezbz88uz][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url]). This collaborative behavior reaches its peak in the GeoGebra forum [url=https://www.reddit.com/r/geogebra/][img]https://www.geogebra.org/resource/scjbyz2p/0tuzuVw455vxurEw/material-scjbyz2p.png[/img][/url].[/color]

[color=#999999]Author of the construction of GeoGebra: [url=https://www.geogebra.org/u/rafael]Rafael Losada[/url].[/color]