Points to Line

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10-17-2023 02:28 AM
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HansÖiås
New Contributor

Hi,

What type of lines gets created using "Points to Line" ?

I need to create some geodesic lines from points I originaly have in an Excel table but they are imported to ArcGIS PRO 3.1.

Hansis_0-1697534202782.png

The coordinate points has an identifying field to determine what coordinate points should be used for what line and I can easily create the lines using points to line, BUT there is no option to select what type of line that should be created as in "XY to Line" that has the options:

Specifies the type of line that will be constructed.
Geodesic— A type of geodetic line that most accurately represents the shortest distance between any two points on the surface of the earth will be constructed. This is the default.
Great circle—A type of geodetic line that represents the path between any two points along the intersection of the surface of the earth and a plane that passes through the center of the earth will be constructed. 
Rhumb line—A type of geodetic line, also known as a loxodrome line, that represents a path between any two points on the surface of a spheroid defined by a constant azimuth from a pole will be constructed.
Normal section—A type of geodetic line that represents a path between any two points on the surface of a spheroid defined by the intersection of the spheroid surface and a plane that passes through the two points and is normal (perpendicular) to the spheroid surface at the starting point of the two points will be constructed. The normal section line from point A to point B is different from the line from point B to point A.
Planar line—A straight line in the projected plane will be used. A planar line usually does not accurately represent the shortest distance on the surface of the earth as a geodesic line does.

To use the "XY to line" doesn't work for me as I have several node points that should be connected along the line, and those tools needs a start and end point per line derived from different input fields.

Is it safe to assume that the line created by "Points to Line" will by default be a Geodesic line as that is noted as the default linetype for the "XY to Line" tool?

I can't find any information of what the linetype will be in the helptexts for both ArcMap and ArcGis Pro.

Thanks,

Hans

 

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4 Replies
DanPatterson
MVP Esteemed Contributor

Your data aren't currently in the form to use

XY To Line (Data Management)—ArcGIS Pro | Documentation

Your data will need to be rearranged.

In any event,  The line created needs to be given a defined geographic coordinate system which matches the long/lat coordinates.

If you want intermediate points or it to be densified by a geodesic segment then process the result from above with

Geodetic Densify (Data Management)—ArcGIS Pro | Documentation


... sort of retired...
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HansÖiås
New Contributor

I am aware that the coordinate list isn't fit for use with the XY to Line tool, but was hoping that there where another way to do it using a tool similar to  "point to line". But it appears as the Point to line simply draws a straight line regardless of what reference is given to the map presentation.
The dataset has been assigned the correct geodetic reference.

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DuncanHornby
MVP Notable Contributor

If you look at the tool in toolbox you will observe that it has a script icon which means its a python script and these you can look at the source to fully understand what the tool is doing.

DuncanHornby_0-1697542443248.png

Simply right click on tools and select > properties > Execution.

If you search the source code for the lines that have arcpy.Polyline() this is where they construct the polyline geometry from an array object and if you search for the array you simply observe them adding points to it. So no fancy conversion is happening.

From this you can conclude that the lines built are in the coordinate system you have provided the points in, in your case looks like WGS84.  You need to go back to the person who supplied them to you to see if they were constructed in a specific manner.

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HansÖiås
New Contributor

Hi,

It seems as only the endpoints are stored when the "point to line" tool is used as the line becomes straight regardless of what projection the map is shown in.

I will have to rearrange the dataset and use the "XY to Line" tool instead, even that it will take some time to do it.

Thanks,

Hans

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