YOUR COORDINATE SYSTEMS IN AUTOCAD DON’T ALIGN, NOW WHAT? READ ON…
World Coordinate System
Sometimes we have to roll up our sleeves and get into the details! At ECI Technologies, we share some of our technical knowledge to give you a deeper understanding of the essential topics critical to successfully executing your earthwork projects. You understand the criticality of control points in job sites which are highlighted in our blog, Everything You Need to Know about Construction Site Control Points. This blog focuses on Coordinate Systems in AutoCAD and what happens when they don't line up.
Coordinate Systems in Construction
Coordinates have been used in construction dating back to ancient Egypt – basically ever since there was a need to determine and describe a point's location. It is common practice that the coordinate method is used for the construction of buildings, bridges, highways, utilities, and site work. Understanding coordinate systems and how one wrong number can cause an entire project to be inaccurate are necessary for those using coordinates.
Challenges with Coordinate Systems in AutoCAD
AutoCAD - 2D and 3D software
Today, most projects have coordinate systems because of CAD design. Often, the coordinate systems being used differ between what the architect uses versus what the civil engineers use versus what the structural engineers use versus what the surveyors use. As a result of the different systems, the measurement units differ, and the plans don't align. For example, when an architectural drawing, which is often done in inches or architectural units, is overlaid on top of a civil drawing, usually done in decimal feet, they do not line up. This creates an issue that needs to be resolved. Another example of the misalignment happens when the civil engineer works in a User Coordinate System (UCS), and it no longer matches the survey coordinate system. There are times when the civil plan coordinates don't fit with the survey coordinates due to their using different metric units for measurement. When working with PDF or paper plans, none of this is a problem, but it is a big problem when you're working with digital files. When you're trying to work with the various digital files to put all the pieces together, it becomes difficult to do so due to the different coordinate systems.
Get Help! Communication and Expertise is the Key
The first piece of advice that we can offer you to solve the issue is to make a call and communicate with the engineers, surveyors, and architects. Let them know that the files you received are in different coordinate systems and that they have to match the field data. Whatever coordinate system is being used for control points and construction in the field is what all the other files must be aligned to. Otherwise, nothing (e.g., AMG, GPS, layout) will work.
Working with an external construction consulting service, such as ECI Technologies, is another solution. Their virtual construction engineers have the depth of knowledge and experience to work through the adjustments that need to be made to the digital files for all of the drawings to align correctly. For further questions on this topic, contact ECI.