Jonathan Hodel, P.E., GISP
Principal
We are seeing a growing interest within the industry in the process of converting floor plans from CAD or BIM format into GIS format, specifically in Esri’s ArcGIS platform. In this post, our primary focus will be on utilizing ArcGIS Pro tools and features to make the conversion, taking a comprehensive look at the steps involved, with an emphasis on Esri’s ArcGIS Indoors solution. So, let's dive right in!
Introduction to ArcGIS Pro and ArcGIS Indoors:
ArcGIS Pro is Esri’s flagship desktop GIS solution. It provides a robust set of tools to create, edit, and analyze GIS data from a variety of sources, including ArcGIS Online or ArcGIS Enterprise, and to share that data with the intended end users. The primary component of ArcGIS Pro is projects. Each project can have multiple map views, layouts, toolboxes, database connections, styles, folders, and locators. Some of the features we’ll look at are available with the basic ArcGIS Pro solution, such as the geo-referencing tools which are extremely valuable when converting floor plans to GIS format. There are also several extensions available for ArcGIS Pro, but for this post, we’ll limit our focus to the ArcGIS Indoors extension, which enables GIS users to create and share user-friendly, interactive, floor-aware maps.
Importing and Geo-referencing CAD and BIM files with ArcGIS Pro
Exploring CAD layers and understanding the importance of spatial references is a key component of the conversion/migration process. When opening CAD files from the ArcGIS Pro Catalog viewer, you will see many different files within the *.dwg file. These files are typically organized by points, polylines, and polygons. These can be brought in individually or as a group.
Typically, these raw files will not have a spatial reference associated with them - that’s where the GIS tools in ArcGIS Pro come in. Selecting the layer in the table of contents and viewing the properties can reveal if there is an associated spatial reference. With the CAD layer still selected in the table of contents, the CAD data menu can provide all of the necessary tools needed for these next steps.
If no spatial reference exists, the results will say ‘Unknown’. If this is the case, users can use the ‘Define Project’ tool located in the menu to define the appropriate projection, typically in local state plane format.
Once a spatial projection has been defined for the CAD files, they can be properly georeferenced using the Georeference tool. This toolbar offers functions for moving, rotating, and scaling the CAD layers to get them in the correct geolocation using the basemap or control points as a reference. When the georeferencing is saved, it creates a *.wld file in the projects folder, which can be copied and renamed to be used with other building floor plan CAD layers if they are referenced with respect to one another.
The above steps can be followed in a similar fashion to define the projection and georeference BIM files before importing them to GIS format.
Migrating CAD and BIM floor plans to GIS format
Once the floor plans have a spatial reference defined and have been properly georeferenced, they are ready to be migrated to GIS format. Data can be migrated manually using the basic export tools in ArcGIS Pro, but the user will be required to create their own data model structure and will not have floor-aware functionality without the ArcGIS Indoors extension.
Migrating floor plans to ArcGIS Indoors:
Importing CAD files to ArcGIS Indoors
The ArcGIS Indoors extension has tools and features that make this process easier and streamline the necessary steps involved. For CAD floor plans, there is an Excel template that comes with the ArcGIS Indoors product files, which can be downloaded after signing in to your My Esri account.
This template allows the user to define the location of CAD source files and the names of the associated layers that will be brought into geodatabase format, specifically a geodatabase that uses the ArcGIS Indoors template data model.
Creating an ArcGIS Indoors Database
The Indoors template database can be created using the ‘Create Indoors database’ geoprocessing tool, which is only available with the ArcGIS Indoors extension licensing. The template data structure includes layers for sites, facilities, sections, zones, and units.
Once the blank geodatabase has been created and the Excel template filled out, the CAD data can be easily migrated to the new geodatabase using the ‘Import Floorplans To Indoors Geodatabase’ found within the Indoors extension.
Importing BIM files to ArcGIS Indoors.
Importing BIM files to ArcGIS Indoors is a slightly different workflow than importing CAD floor plans and does not use an Excel template, but instead has embedded parameters within the ‘Import BIM to Indoors Dataset’ geoprocessing tool. This tool allows users a one-step process to define the source variables from their BIM files and specify which of the corresponding Indoors data layers to migrate them to within the Indoors data model template as described above.
Conclusion:
When floor plans are migrated to the ArcGIS Indoors format, they can be used for a variety of applications including space planning, asset inventories, and routing and wayfinding. The floor plans can serve as the backbone of future indoor GIS applications. Keep in mind that the need for clean CAD and BIM data layers cannot be over-emphasized for successful migration to ArcGIS Indoors.
Feel free to explore the world of CAD to GIS conversion with ArcGIS Pro in the video tutorial below, and don't hesitate to embrace the dynamic features that ArcGIS Indoors offers for comprehensive spatial management. Happy mapping!
