attribute length and shape lenght are not the same

[MatthiasWüthrich]

Hello

I have an attribute table which contains shape_length and attribute_length. The table was created by the Copy traversed source features tool. Attribute length is correct, but shape length is about 1.5 times bigger for the same attribute. If I measure any distance on the map, and compare it to measurements I did on Google maps, the distance is also 1.5 times as big as on Google maps. I guess that this will be a spatial reference issue. I transformed all my data into wgs_1984_web_mercator_auxiliary_sphere. I know that wgs84 isn`t very accurate, but a factor of 1.5 seems to be much more than simply inaccurate.

Any suggestions? Thank you.

[JaySandhu]

Read the following for more info on distance errors with web mercator:

https://blogs.esri.com/esri/arcgis/2010/03/05/measuring-distances-and-areas-when-your-map-uses-the-m... 

Update:

The above link is not available as the Esri blog site has changed. See the link that Dan Patterson has posted for the technical support article.

[DanPatterson_Retired]

Jay... the link goes to the general page...

perhaps this can substitute until you can locate it ... Why are my map, distance and area measurements wrong when using WGS 1984 Web Mercator?

[AbdullahAnter]

Using wrong projection in Switzerland cause a massive error .

If the shape_length is the standard field with feature class in geo-database, that always is correct one as long as you using the correct projection.

in your case you should use projection provide a correct distance such as (WGS_1984_UTM_Zone_32N  / Bern_1898_Bern_LV03C)

[MatthiasWüthrich]

Problem was web mercator. Transformed it and now everything is fine. Thanks alot.

[DanPatterson_Retired]

Why are my map, distance and area measurements wrong when using WGS 1984 Web Mercator?

[AdrianWelsh]

This is a good article! (too bad that all online maps have to use this projection).

[SanneMikkelsen]

I have the same problem in ArcGIS online. The layer is created in online, and the distances differ x2. I thought that it would be the same projection, when my user uses AGOL for it all. How do i transform it in AGOL?