{"id":2611352,"date":"2024-12-04T07:47:33","date_gmt":"2024-12-04T15:47:33","guid":{"rendered":"https:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=2611352"},"modified":"2025-01-03T05:33:02","modified_gmt":"2025-01-03T13:33:02","slug":"why-you-should-think-about-coordinate-systems-when-working-in-3d","status":"publish","type":"blog","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/arcgis-online\/3d-gis\/why-you-should-think-about-coordinate-systems-when-working-in-3d","title":{"rendered":"Why you should think about coordinate systems when working in 3D"},"author":10362,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":{"_acf_changed":false,"_searchwp_excluded":""},"categories":[23771,23851],"tags":[25781,42641,42181,31781],"industry":[],"product":[36551,36561,36601],"class_list":["post-2611352","blog","type-blog","status-publish","format-standard","hentry","category-3d-gis","category-data-management","tag-3d","tag-arcgis-online","tag-arcgis-pro","tag-coordinate-system","product-arcgis-online","product-arcgis-pro","product-developers"],"acf":{"authors":[{"ID":10362,"user_firstname":"Ivonne","user_lastname":"Seler","nickname":"Ivonne Seler","user_nicename":"iseler","display_name":"Ivonne Seler","user_email":"iseler@esri.com","user_url":"","user_registered":"2019-12-20 18:56:39","user_description":"Ivonne is 3D program manager and product owner of the scene layers team. Ivonne started her career at ESRI as product engineer in the mapping team. She joined ESRI\u2019s 3D effort to follow her passion for visualization especially in 3D. What drives Ivonne is to see teams and individuals collaborate to bring new capabilities to ArcGIS users.","user_avatar":""}],"related_articles":"","show_article_image":false,"card_image":false,"wide_image":false,"short_description":"If you work in 3D you need to think about the best fitting coordinate system in XY and Z represented by a vertical coordinate.","flexible_content":[{"acf_fc_layout":"content","content":"

To identify any location on Earth you need to provide its coordinates in x, y, and z. Map makers have used projected coordinate systems to \u201cflatten\u201d the Earth. If you work in 3D you need to think about the best fitting coordinate system in XY. In addition you need the vertical coordinate system to represent Z. <\/span>\u00a0<\/span><\/p>\n

This can be challenging if you are not too familiar with coordinate systems. Here are some guidelines that can help you make the best choice.<\/span>\u00a0<\/span><\/p>\n

Determine<\/span> the best fitting coordinate system for your use case<\/span><\/span>\u00a0<\/span><\/h2>\n

ArcGIS supports many different coordinate systems including custom coordinate systems. <\/span>The first question<\/span>s<\/span> you will need to answer <\/span>are about the geospatial context you<\/span> want to work <\/span>in<\/span>. <\/span>Here are some examples of the typical questions:<\/span><\/span>\u00a0<\/span><\/p>\n

Will the layer <\/span>represent<\/span> global data?<\/span><\/span>\u00a0<\/span><\/h3>\n

For instance,<\/span>\u00a0you are <\/span>using<\/span> data that <\/span>is<\/span> collected on different <\/span>continents<\/span> or shows data for the entire Earth<\/span>,<\/span> and you want to visualize and work with the data in one layer it might be best to use a global coordinate system like WGS 1984<\/span> and a corresponding vertical coordinate system like EGM 96 or EGM2008.<\/span><\/p>\n

Are you planning to show the layer together with a basemap?<\/span><\/span>\u00a0<\/span><\/h3>\n

In addition you might need reference layers together with your data. ArcGIS provides 2D and 3D basemaps that you can use <\/span>creating a scene<\/span>, for example. In addition, if<\/span>\u00a0you are working with feature layers, the data can be projected into the coordinate system of the <\/span>web <\/span>scene<\/span>.<\/span> For other layer types like scene <\/span>layers, vector tile, or imagery layers,<\/span> you will need to <\/span>define the same coordinate system as the basemap<\/span>.<\/span> ESRI provided basemaps are compatible with the coordinate system WGS 1984 or Web Mercator. <\/span>In case you are working in ArcGIS Pro you <\/span>do not<\/span> have to worry about coordinate systems because all <\/span>layers<\/span> can be <\/span><\/span>projected on the fly<\/span><\/span><\/a>.<\/span><\/span>\u00a0<\/span><\/p>\n

Are there<\/span> legal requirement<\/span>s<\/span>?<\/span><\/span>\u00a0<\/span><\/h3>\n

There are many factors that might determine what type of coordinate system is required for your data. For example, if your layer represents a construction site you might be restricted to a specific coordinate system. Anyone on the project can work with your geospatial data because the same coordinate system is used.<\/span>\u00a0<\/span><\/p>\n

Sometimes you might have to comply with government requirements to provide geospatial data in the country or state coordinate system.\u00a0<\/span>\u00a0<\/span><\/p>\n

Creating new data or projecting data<\/span>\u00a0<\/span><\/span>\u00a0<\/span><\/h2>\n

You can create <\/span>new feature classes<\/span><\/a> or <\/span>project<\/span><\/a> existing data including <\/span>raster<\/span><\/a>. However, if you do not define a vertical coordinate system ArcGIS assumes that the vertical heights are gravity related and have the same unit as the horizontal XY coordinate system. If your data are in a geodetic coordinate system, the vertical unit is assumed to be in meters.<\/span>
\nWhen you work in 3D it is best practice to define the vertical coordinate system. This way you assure that the data can always be aligned with other data in a different coordinate system by applying a transformation, for example.<\/span>\u00a0<\/span><\/p>\n

Additionally, if you need to change the coordinate system of your 3D data, you can use the geoprocessing tool <\/span>project<\/span><\/a> to create data in the required coordinate system. You can use the <\/span>Projection and Transformation toolset<\/span><\/a> to work with coordinate systems and transformations.<\/span>\u00a0<\/span><\/p>\n

Choosing the horizontal coordinate system<\/span><\/span>\u00a0<\/span><\/h3>\n

For instance, for your global <\/span>3D data<\/span>, you must choose WGS 1984 as coordinate system.<\/span> Usually you visualize g<\/span>lobal data in a global scene. <\/span>Within a global scene <\/span>you can use 3D basemaps<\/a> provided in the living atlas<\/span> and show your data in a global context. For example, you can zoom in and out of the data and see the Earth.<\/span><\/span>\u00a0<\/span><\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2611542,"id":2611542,"title":"3D basemap","filename":"zoom7.gif","filesize":6991341,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/arcgis-online\/3d-gis\/why-you-should-think-about-coordinate-systems-when-working-in-3d\/zoom7","alt":"3D basemap","author":"10362","description":"Zoom to Notre Dame in a global scene.","caption":"Zoom to Notre Dame in a global scene.","name":"zoom7","status":"inherit","uploaded_to":2611352,"date":"2024-12-04 14:00:46","modified":"2024-12-04 14:01:09","menu_order":0,"mime_type":"image\/gif","type":"image","subtype":"gif","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":600,"height":450,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7-213x200.gif","thumbnail-width":213,"thumbnail-height":200,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","medium-width":348,"medium-height":261,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","medium_large-width":600,"medium_large-height":450,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","large-width":600,"large-height":450,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","1536x1536-width":600,"1536x1536-height":450,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","2048x2048-width":600,"2048x2048-height":450,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","card_image-width":600,"card_image-height":450,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/zoom7.gif","wide_image-width":600,"wide_image-height":450}},"image_position":"center","orientation":"horizontal","hyperlink":""},{"acf_fc_layout":"content","content":"

You can choose a <\/span>projected coordinate system <\/span><\/a>if your data represents a smaller area like a construction site<\/span>. For example, in the Netherlands the official statewide coordinate system is RD in XY and NAP in Z. If you choose the same coordinate system your data will draw correctly with other publicly available data. <\/span>\u00a0<\/span><\/p>\n

GIS systems usually contain both 2D and 3D data and it is important to be able to bring all data together. You should choose the same horizontal XY coordinate system for your 2D layer and 3D layer. In addition you should consider the vertical coordinate. <\/span>\u00a0<\/span><\/p>\n

C<\/span>hoose a corresponding vertical coordinate system for your 3D layers<\/span><\/span>\u00a0<\/span><\/h3>\n

For any of your data that has Z values your should define a vertical coordinate system. For example, w<\/span>hen you <\/span>represent<\/span> 3D data<\/span>\u00a0you need to make sure that the z value can be measured anywhere in your scene. <\/span>This is also true for any feature data like points or lines. Without a<\/span> vertical coordinate system, you might encounter<\/span>\u00a0distortion<\/span> due to the projection of the data in XY only.<\/span> With a vertical coordinate system you can assure that at any given point the data can be drawn correctly.<\/span><\/span> If you edit a feature without a VCS your feature might not be at the correct position. Like in the example below, where the red cube is position correctly on the ground while the cube without VCS is floating above.<\/span><\/p>\n"},{"acf_fc_layout":"image","image":{"ID":2611482,"id":2611482,"title":"VCS","filename":"VCS.gif","filesize":237962,"url":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS.gif","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/arcgis-online\/3d-gis\/why-you-should-think-about-coordinate-systems-when-working-in-3d\/vcs","alt":"3D layer with vertical coordinate system.","author":"10362","description":"3D layer with vertical coordinate system aligning correctly with the ground.","caption":"3D layer with vertical coordinate system aligning correctly with the ground.","name":"vcs","status":"inherit","uploaded_to":2611352,"date":"2024-12-04 11:21:17","modified":"2024-12-04 11:22:07","menu_order":0,"mime_type":"image\/gif","type":"image","subtype":"gif","icon":"https:\/\/www.esri.com\/arcgis-blog\/wp-includes\/images\/media\/default.png","width":600,"height":484,"sizes":{"thumbnail":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS-213x200.gif","thumbnail-width":213,"thumbnail-height":200,"medium":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS.gif","medium-width":324,"medium-height":261,"medium_large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS.gif","medium_large-width":600,"medium_large-height":484,"large":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS.gif","large-width":600,"large-height":484,"1536x1536":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS.gif","1536x1536-width":600,"1536x1536-height":484,"2048x2048":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS.gif","2048x2048-width":600,"2048x2048-height":484,"card_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS-576x465.gif","card_image-width":576,"card_image-height":465,"wide_image":"https:\/\/www.esri.com\/arcgis-blog\/app\/uploads\/2024\/12\/VCS.gif","wide_image-width":600,"wide_image-height":484}},"image_position":"center","orientation":"horizontal","hyperlink":""},{"acf_fc_layout":"content","content":"

Here are simple rules to follow when choosing the vertical coordinate system:<\/span>\u00a0<\/span><\/p>\n