{"id":2029552,"date":"2023-07-27T12:51:04","date_gmt":"2023-07-27T19:51:04","guid":{"rendered":"https:\/\/www.esri.com\/arcgis-blog\/?post_type=blog&p=2029552"},"modified":"2023-07-27T13:37:43","modified_gmt":"2023-07-27T20:37:43","slug":"using-user-specified-coordinate-systems-in-arcgis-geobim-projects","status":"publish","type":"blog","link":"https:\/\/www.esri.com\/arcgis-blog\/products\/geobim\/aec\/using-user-specified-coordinate-systems-in-arcgis-geobim-projects","title":{"rendered":"Using User-specified Coordinate Systems in ArcGIS GeoBIM Projects"},"author":292952,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":{"_acf_changed":false,"_searchwp_excluded":""},"categories":[23771,615021],"tags":[763792,30371,169802],"industry":[],"product":[761602],"class_list":["post-2029552","blog","type-blog","status-publish","format-standard","hentry","category-3d-gis","category-aec","tag-arcgis-geobim","tag-bim","tag-coordinate-systems","product-geobim"],"acf":{"short_description":"Learn how to select coordinate systems with custom and national basemaps for ArcGIS GeoBIM Projects. ","flexible_content":[{"acf_fc_layout":"content","content":"

Until the June 2023 release of ArcGIS GeoBIM<\/a>, Web Mercator was the only supported coordinate system in ArcGIS GeoBIM<\/a> that could be used to create feature layers, web maps, and issues. Now, you can select a basemap with a different coordinate system for your ArcGIS GeoBIM Projects.<\/p>\n

You must have a custom basemap gallery in your ArcGIS Online organization that hosts your own basemaps in addition to Esri\u2019s default basemaps in Web Mercator. For more information, see the create a custom basemap gallery for your organization<\/a> blog article. To learn how to customize Esri vector basemaps with your own colors, patterns, icons, and labels, follow the personalize your maps with custom basemap styles<\/a> tutorial.<\/p>\n

Understand map projections and coordinate systems<\/strong><\/h2>\n

Transforming any geometry from a curved surface to a flat one involves a mathematical formula called the map projection, since the earth is ellipsoid, and maps are flat. A map projection transforms latitude and longitude to x, and y coordinates (in feet or meters) in a projected coordinate system.<\/p>\n

The process of flattening the earth causes distortions (see figure below) in several spatial properties, such as area and shape. There isn\u2019t a perfect projection that can preserve all these spatial properties. As a result, all flat maps get distorted to some degree.<\/p>\n"},{"acf_fc_layout":"gallery","gallery_images":false},{"acf_fc_layout":"content","content":"

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Geographic information systems (GIS) allow you to choose from many map projections to best represent your map. Esri\u2019s ArcGIS technology now supports 6,114 projected coordinate systems that use 106 different map projections. Each projection system is optimized to offer suitability for representing a particular portion of the earth’s surface.<\/p>\n

Projection systems, as a result, aim to preserve distance, area, shape, or direction as close as possible to the real world. Some map projections minimize distortion in one property at the cost of another, while other ones strive to balance the overall distortion. As a GIS user, you can decide which properties are most important for your work and choose a projection that suits your needs.<\/p>\n

Selecting the right coordinate system with the right projection is critical if you are doing the following:<\/p>\n