topic Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates? in ArcGIS Pro Questions

How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

Craig_Eissler_Iceman — Tue, 12 Sep 2023 21:08:17 GMT

How do you create a New Shapefile with 'Shape_geometry fields' (Shape_leng and Shape_area) in geographic coordinates (longitude-latitude in degrees)?

...The only thing I can think of is to create it in a Geodatabase feature class first, then export it to a Shapefile.
Is that true?

Another thing I'm wondering is how these were created before the advent of the Geodatabase some 20 or so years ago?

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

RhettZufelt — Tue, 12 Sep 2023 21:58:36 GMT

In catalog right click on folder you want to create the shapefile, select New, Shapefile.

Fill in the name, type, and set coordinate system to the one you want. Click Run.

Can also use the Create Feature Class GP tool, just put location as a writeable folder, and add .shp to the end of the filename.

Open the Calculate Geometry Attributes GP tool, select the input shapefile, enter the field names and Property (limited to 10 characters since a shapefile), and click Run.

Done.

Of course, unlike GeoDatabases, the shape fields in a shapefile are static, so, since this is a new 'empty' shapefile, only the fields will be added, but will not update dynamically.

If something changes (additions, modifications), you will need to re-calculate the geometry fields which can be done with the tool, or right-click the geometry field in the attribute table and select Calculate Geometry.

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

Craig_Eissler_Iceman — Tue, 12 Sep 2023 22:09:48 GMT

Thanks, but sorry; what I'm trying to say s that Degrees (or Square Degrees) is NOT an option for specifying the 'Area Unit'.

How were you able to do it?

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

DanPatterson — Tue, 12 Sep 2023 22:17:27 GMT

Calculate Geometry Attributes (Data Management)—ArcGIS Pro | Documentation

specify the coordinate system that you want the are units in... which would have to be a projected coordinate system of course

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

Craig_Eissler_Iceman — Tue, 12 Sep 2023 22:44:32 GMT

Exactly, that's what I am saying!

...So, back to my original question:

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

RhettZufelt — Tue, 12 Sep 2023 22:54:22 GMT

I was not able to do "it". I was able to create an empty shapefile in GCS with decimal degrees.

However, to add geometry fields/values, I had to pick a unit that applies to a length or area, not an angle.

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

Craig_Eissler_Iceman — Tue, 12 Sep 2023 23:10:10 GMT

Exactly, that what I am saying; so, back to my original question!

I'll try to word it differently.

..."When I see a Shapefile with Shape_geometry fields in degrees -- which I see ALL THE TIME -- how did that happen?"

The only thing I've tried that worked is to first create in a Geodatabase then export it as a Shapefile.

...Is this the ONLY way?

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

RhettZufelt — Tue, 12 Sep 2023 23:19:11 GMT

That is a good question as I don't recall ever seeing an Area/Length column in degrees. Could you provide an example, maybe that will help figure out what you are seeing and how to accomplish it.

Also, if you could show how you'd convert 500 square meters to square degrees, might also help to solve it.

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

Craig_Eissler_Iceman — Tue, 12 Sep 2023 23:32:47 GMT

...Seriously, I see those Shape_geometry fields in Degree values all the time! ...in both GDB Feature Classes and Shapefiles.

And yes, I already know the answer as to how to make that happen, as I've stated. ...In the case of a Shapefile, though, I just didn't know if there was "some other way" that didn't involve creating it in a GDB first.

At this point, I'll just conclude that I am correct; that the only way is by creating the GDB Feature Class first ...then, exporting it to a Shapefile.

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

DanPatterson — Wed, 13 Sep 2023 01:00:45 GMT

We missed this... obviously seen before

Shape_Length and Shape_Area of Geographic Coordina... - Esri Community

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

Craig_Eissler_Iceman — Wed, 13 Sep 2023 13:03:06 GMT

Yes, ...not exactly the question I had, but certainly related to it. Thanks for sharing.

Re: How do you create a New Shapefile with 'Shape_geometry fields' in geographic coordinates?

Craig_Eissler_Iceman — Fri, 15 Sep 2023 14:45:40 GMT

Thanks for sharing that Post link!

And, so, yes, Shape_geometry fields are automatically added to a Shapefile when certain geoprocessing tools are run. ...something that I had forgotten about, but does explain how those fields likely get created.

And, yes, the other Post also states a point related to this, which is that ArcGIS will provide those Shape_geometry field calculations in "geographic (lat/long degrees) units" if the Input layer is in those units. However, you cannot manually calculate these in geographic degree coordinates. Interesting...