# I have a table with begining and ending latitudes and longitudes for trawls and would like to calculate the length of each trawl. Is there a way to automate this rather than measure each one?

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04-04-2016 01:22 PM
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New Contributor

I am using ArcGIS 10.6.

5 Replies
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Occasional Contributor

Jose,

There is no ArcGIS 10.6, the latest release is 10.3...If you go to help -> about arcmap it will tell you what version you are running.

I would look into the "Points to line tool":

The key to this is the "Line" field and "Sort" field. So do your trawls have a unique id for each one?

Trawl A, Trawl B..etc...

And then in your sort field you will have to add a 1,2... in the way you want the line to go.

If you have a unique ID this can be done using python, and consecutive numbers. I would honestly do it in Excel because it is easier.

Then you run the tool and it will connect each point based on the Line and Sort field..so it will draw a line from Trawl A 01 to Trawl A 02, and then move onto Trawl B 01, etc...

You can then use field geometry to calculate the length of the resulting lines. just be sure your data is projected to a projected coordinate system because the field geometry will not work on a layer with a geographic coordinate system.

I hope this helps!

Dan

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Regular Contributor III

See this thread Distance Between 2 Points

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Occasional Contributor

I stand corrected the latest release is actually 10.4 in February.

That's for ArcMAP  what ArcGIS software are you using? Is it an ESRI product?

Wes,

Your link is great but if you are using a Lat and long to calculate the distances then you have to convert from Decimal Degrees to feet and this is very difficult to do. But there are tools out there. This is a link to a stack exchange question about converting from decimal degrees to feet.

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MVP Esteemed Contributor

Here is how I would approach this:  use the points to line tool as described, making sure the output feature class is in the the proper GCS  coordinate system  Then project the original output into a projection that fits the area of interest.  Re-calculate the geometry length of lines to the units of choice in the projected feature class.

You might be able to skip the projection step if you set your output environments to the projection of choice, and then re-calc the geometry length.

Un-testedNo warranties, no promises, no remorse...

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MVP Esteemed Contributor

you can project the data

then recalculate your coordinates in projected units

then do the point to line thing.

or

you can skip a step by using

Add Geometry Attributes—Help | ArcGIS for Desktop if you just connect the points, then you can recalculate geometry and other attributes after or use those of a projected data frame.

If your distances are quite large, then you may wish to do this in geographic coordinates, first, perhaps densifying the line before projecting.

If all this is too much,... connect the dots as suggested, use the add geometry tool to calculate the lengths and coordinates of the first and last point in the projected coordinate system.