In many scenarios, particularly in the built environment, you need to construct new features based on a series of measurements and offsets from existing features in your data. Although ArcGIS supports a variety of ways to create features using a combination of snapping and constraints, more permanent construction geometries are appropriate in some scenarios.
Rather than resorting to storing construction lines in a feature class, an alternative method to support construction lines is with the temporary guide functionality available by installing the Construction Guides add-in written by Esri’s Editing development team. You can use the guides to build a series of geometries to assist you with completing complex constructions for use while creating new features and modifying the shape of existing features. The guides can be created with common editing constraint capabilities, such as making geometry parallel to an existing feature, at distance from a known location, or at a specific x,y coordinate. You can use snapping both when placing the guides and creating features in relation to them, allowing you to precisely locate a position based on the construction guide geometry.
To use the Construction Guides add-in, download it from the Editing Labs group on ArcGIS.com and double-click the file to install it on your machine. When you start ArcMap you have access to the Guides toolbar, which hosts all the tools to create and manage the temporary geometries that can be used in constructions. Creating construction guides is a straightforward process. You just click the type of guide on the Guides toolbar and define its geometry on the map. You can do this interactively, or if you have specific values to enter, the tools support the ability to specify them using keyboard shortcuts.
To illustrate how the guides can be utilized during feature creation, I am going to digitize a new residential building with them. Once I position the guides, I use the regular feature construction tools to create the building feature. I have been given several measurements that I can use to place the guides, and ultimately, the new building. The northwest corner of the building is 12.5 feet from the corner of the lot. To locate this position, I first use a circle guide and snap to the corner of the lot to place the center point of the circle. I then drag a circle, but rather than clicking to define the circle’s diameter interactively, I can press the R key and enter 12.5 to define the radius. I also know that the edge of the building is offset eight feet from the western lot boundary. I can use the Line Guide tool to create a guide from that lot boundary and specify a distance of eight feet by pressing the D key. Similar to entering values in built-in editing dialog boxes, guide measurements are entered in map units.
With these two guides in place, I can now begin to create the building feature. Since the rresidential building is rectangular in shape, I can use the Rectangle construction tool to create it. To place the first corner of the building, I need to turn on Intersection Snapping from the Snapping toolbar and snap to the intersection of the circle and line guides.
Once I have created the corner of the building at that intersection, I set the orientation of the building in the lot by snapping along the line guide I created from the lot boundary. I can then right-click to access a menu that allows me to enter the length and width dimensions of my building.
The building feature is completed once I finish entering the measurements. The guides remain after the feature is created, so I could continue to use them for other editing tasks. In this case, I don’t need them any longer, so I can click Clear Guides to remove all the guides.
This is just one illustration of using guides to locate features precisely. In future blog posts, I’ll explain how this sample was developed and how you can extend your own code to utilize some of the same capabilities shown here.
Introducing Editing Labs on ArcGIS.com
The Construction Guides add-in is one example of how Esri’s Editing development team is building tools, prototypes, and practical examples and sharing them with you. We are adding these to an ArcGIS.com group called Editing Labs, which provides an opportunity, along with the ArcGIS Ideas site, for you to share feedback on some work that the Editing team is investigating. Tell us what you think about Construction Guides and our other samples by adding comments on the individual items in the Editing Labs group. We’ll be adding new content regularly to Editing Labs, so check back often.
Content provided by Doug (ArcGIS Editing Team)