Drawing new layer (add map notes) on arcGIS online, getting the total area

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09-16-2020 06:05 AM
Sarah-CodyKnight
New Contributor II

I am trying to put together an activity for school groups to introduce them to ArcGIS online in an interactive and meaningful way without the need for people to go outside to take points/lines/polygons. Our activity is being built around arcmaps online, and we are getting them to draw polygons over specific habitat types (woodland, savanna, prairie etc.). For each of those new polygons we need to know the area, and I cannot figure out a simple way to get the area of a newly drawn polygon (created using "add map notes"). I know that there is the measurement tool, but that means they have to draw essentially two polygons for each new polygons. I feel like there has to be an easier and more straightforward way to get the area out of these new shapes. Any ideas?

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5 Replies
WillBraganza
Esri Contributor

Hey Sarah!  Another user might have more insight into this but I just did some quick testing and if you're using the map notes to create the polygons then I'm not familiar with a way to easily calculate the area from that.  '

However, if these were features created in ArcGIS Pro or ArcMap and then published to ArcGIS Online you're students could calculate the area with the attribute table (this is of course is reliant on how much of our software outside of ArcGIS Online that the students are familiar with).

Just my two cents!  I hope your activity goes well!  

EDIT:  I wanted to include this article in case it is helpful to you -  FAQ: Is it possible to calculate area in ArcGIS Online?   

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ManishPatel
Esri Contributor

Sarah-Cody Knight‌, this can be achieved with some pre-configuration done to a feature layer that can be used for creating polygons. 

What I have done to achieve this is as below:

  • Create a feature layer that can create polygons.
  •  Add the feature layer to the web map with full editing control.
  • Once the layer is added click on the 3 dots for more options

more options

  • Select 'Create labels'
  • Under the Label Features, options select Text dropdown and scroll down to 'New Expression'

new expression

  • Select Functions on the right and select the 'Area' function

area function

  • Click 'Test' to verify if the results look fine, you can change the format or units if you would like.
  • Save this web map and the students can use the web map to draw the polygons. The attributes can be used to store the descriptions

attributes

  • Once the polygon is drawn it will automatically create the area label. TADAA!

area label

Hope this helps.

Cheers,

Manish

Cheers,
Manish
ManishPatel
Esri Contributor

Sarah-Cody Knight‌ wondering if you got a chance to view the above mentioned solution.

Cheers,
Manish
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Sarah-CodyKnight
New Contributor II

Hi Manish,

I will try the above suggestion, as it does seem to circumvent the issue and I very much so appreciate that. We had to change the activity a little bit and ended up just providing our own polygons for the activity, including creating a buffer layer to represent forest succession in a prairie habitat.

Thank you for your help,

Sarah-Cody

ManishPatel
Esri Contributor

Sarah-Cody Knight‌, you are most welcome. I wish I would have provided the workaround a little earlier :)

Feel free to reach out to us anytime you need any further help.

Please don't forget to mark the question as answered, this will help other users, easy to find solutions.

Good luck and cheers,

Manish

Cheers,
Manish