A Computer-Aided Design (CAD) drawing file is an acceptable format to use to create a GIS Deliverable. The Department will accept CAD files that can be imported into GIS,
but a shapefile is the preferred GIS Deliverable for polygons. The CAD requirements for GIS Deliverables are outlined in Section 3.2 of the
Administrative Requirements for GIS Deliverables. The following guidance outlines issues that may be encountered and need to be addressed when either submitting a CAD
.dwg file or prior to converting a CAD drawing to an Esri Shapefile.
For a CAD file to be imported into ArcGIS, the file name can NOT include spaces or hyphens and only one dot between the file name and extension is allowed. If the name
contains spaces or hyphens, then substitute both characters with underscores.
The following CSRR naming protocol for GIS Deliverables will make sure the file name will not cause a problem when processed. The file name shall begin with the Program
Interest number of the site, followed by an underscore, followed by the submission date with a format of 'yyyymmdd', and then followed by the valid Submittal Type
Acronym used in the Subject Line of the Submittal. Please include only one dot in the file name, between the file root name and file extension and use an underscore
instead of a dash.
File Naming example for CEA submission
Site Name: XYZ Inc.
CSRR Program Interest number: 013164
Date of Submittal: May 30, 2020 (in 'yyyymmdd' format)
Correct File Name for this example: 013164_20200530CEA
Note: Where multiple institutional controls exist for a single Program Interest, the correct ascending submission type name [i.e., CEA1, CEA2, etc. must be in the file
name. So, second submittal for the example above, would have a name of 013164_20200530CEA2.
2D CAD files only
The GIS Deliverable must be a two-dimensional (2D) CAD drawing. A 3D CAD drawing or any drawing with Z values cannot be processed and will be returned for corrections.
The Shape of Concern must be a Polygon
The boundary shape must be provided as a polygon not as a polyline. The automated process cannot create a polygon from several polylines as they do not always close
Source: ArcGIS Pro - What is CAD Data?
Simplify the Drawing
A simple solution to assist in the import process is to copy the features of concern into a new CAD file and submit only the polygons that are required to be submitted.
Removing all clutter, including all other CAD features except those that are required for the GIS Deliverable submittal.
Over time, drawings get bloated with unnecessary and outdated information. This can include unused layers, line types, fonts, styles, and blocks. By getting rid of
these extraneous items you keep your drawings lean. Lean drawings also are less likely to become corrupt. The following types of unused named objects can be removed
from your CAD drawing using the PURGE command: block definitions, dimension styles, groups, layers, line types, and text styles. It will also remove zero-length geometry
and empty text objects.
Source: Autodesk: Three Quick Ways to Clean Up
an AutoCAD Drawing: Tuesday Tips with Brandon (May 2020)
A problem can occur during the import process if the polygon of concern is part of a compound object. GIS can not import shapes that are associated with compound objects.
The EXPLODE command in CAD will convert a complex object into its component objects and may allow features that are inaccessible in GIS to be available. It is
recommended to apply the EXPLODE command at least once, although the command may need to be applied several more times since blocks may be embedded up to nine levels
deep. To explode a file in AutoCAD, navigate to Edit > Select all, and apply the EXPLODE command to explode the blocks.
Source: ESRI Technical Support: How to Display and AutoCAD Drawing File in ArcMap (November
2019 - refer to Steps 4 and 5)
Inserting Fields into CAD
All GIS Deliverables require the user to insert at least one additional field into the CAD .dwg file. The exact schema required depends on the Deliverable Type. The
schema details are provided in Section 5 of the Administrative Requirements for GIS Deliverables
To insert a field in AutoCAD text:
- Select the AutoCAD text in which you want to insert a field.
- Right-click and click Text Edit.
- Right-click at the point within the text where you want to insert a field and click Insert Field.
- Define the field and its format.
- Click OK
Source: AutoCAD Architecture: To Insert a Fields in AutoCAD Text (March 2017)
What is georeferencing?
Georeferencing means that the internal coordinate system of a digital map can be related to a ground system of geographic coordinates. A georeferenced digital map
has been tied to a known Earth coordinate system, so users can determine where every point on the map is located on the Earth's surface.
Source: USGS: What Does "Georeferenced" Mean?
Georeferencing in CAD
CAD Drawings must be georeferenced using the New Jersey State Plane Coordinate System, North American Datum of 1983 (NAD83), using feet as the units of measure and
defined in "model space" so that in can be projected in GIS to the correct location within the State of New Jersey.
Importing orthoimagery into CAD
Orthoimagery for the State of New Jersey is available through the NJ Geographic Information Network
website. From the NJGIN website, perform the following:
- Select Imagery under Find GIS Data on the right side of the screen
- Follow the instructions for AutoCAD Users
- On the ArcGIS Online item page, scroll to the bottom.
- On the bottom right of the page, copy the URL of the WMS for use in AutoCAD and other OGC-compliant client software.
Georeferencing a CAD Drawing
Once the appropriate orthoimagery is available in AutoCAD, perform the following:
- Draw your GIS polygon in CAD based on the using the underlying orthoimagery as a reference
- Name the layer file(s) in your CAD drawing as outlined in the Administrative Requirements for GIS Deliverables
- Ensure that the GIS Deliverable was created as a polygon, not a polyline.
Source: AutoDesk Knowledge Network: How to Georeference Existing Linework (November 2019)