Tag Archives: old building

Overlapping Photogrammetric systems

View of Point Cloud from side/rear

Spending a lot of time seeing how different photogrammetric systems and point cloud software packages speak to one another. sometimes the interface is elegant, sometime not so much…

Childs Restaurant -2

Sheet 1 with rectified images "thawed"

Sheet 2 with rectified images "frozen"

Childs Restaurant

Sheet 3 with some rectified images "thawed", others "frozen"

2 boards prepared to illustrate hybrid drawing concept

Board 1

Board 2

completed line drawings

Trinity Episcopal Church

Overview of Sheets prepared for Trinity Episcopal Church in Renssalaerville, NY

Drawing with a few rectified images "unfrozen" in the AutoCAD drawing.

Photogrammetry of Ruins

Rosewell Ruins

Rosewell Ruins

In 2005 While I was running the digital documentation studio for Frazier Associates I enjoyed working on this challenging project for the Rosewell Foundation.  My task was to create accurate, architectural documentation of the  remaining masonry walls of this once grand house on the York river in Gloucester County, Virginia. You can read more about the house here.

Documenting ruins is a little different than a standing building.  The goal is less about presenting a description of building in its “platonic essence” and more about presenting it as it actually is at this moment in time.  Capturing the way a wall, tower, or chimney is leaning becomes rather important!  To this end, I prepared the building prior to the photo shoot by fixing special targets that could establish a level datum line (using a laser level).

Rosewell Documentation (interior sufaces)

Rosewell Documentation (interior sufaces)

The drawings and photographs produced for this project were used by architects Mesick Cohen Wilson Baker to create a “Blueprint for the Preservation of the Ruins at Rosewell” which consisted of a history, an structural analysis, an archaeological report, and stabilization plan.

Rosewell Ruins (exterior surfaces)

Rosewell Documentation (exterior surfaces)

Franklin & Marshall Exterior Survey

Old Main at Franklin and Marshall

Old Main at Franklin and Marshall

Last spring I did some work at Franklin and Marshall College in Lancaster, PA.  I prepared a combination of measured drawings in CAD linked  to rectified photographs of the three oldest structures on the campus. These were then used as base documentation for an assessment of the existing conditions of the masonry surfaces across the extent of these buildings’ exterior facades.

The sequence of this work went roughly as follows:  I first shot photos of all of the buildings from points of view available on the ground (using a specially calibrated digital SLR).  Back in my offices in Virginia I used photogrammetric software to “back calculate” the camera stations and to make precise 3-D measurements of points on the three structures.  I used this dimensionally accurate point cloud as a reference to create rectified photographs of the surfaces visible from grade.

F and M Old Main Rear Elevation

F and M Old Main Rear Elevation

Using the point cloud and the rectified photographs I then created measured line drawings of the structures and laid them out onto tabloid size sheets for use in the field.  These were taken by hand up into an aerial lift so that conditions could be noted with a fair degree of accuracy once assessment were made both visually and manually.

tabloid size field sheet with notes

tabloid size field sheet with notes

Once the assessment was completed the data recorded on the field sheets was entered in the CAD drawings.  At this point the line drawings in CAD were enriched by a mosaic of rectified photographs visible inside of AutoCAD.  This allows for an accurate transfer of notes from the field to eventual construction documents.  A sketch of an area or region can be transferred to CAD and become dimensionally reliable.  This is a very important step because it provides for an accurate tally of areas to be treated in one way or another.

aerial lift

aerial lift

Since the main structure was rather tall, I also returned to the site to go up in the aerial lift to collect more photographs to further enrich my drawings with better rectified images of areas that were either blocked by vegetation, neighboring buildings, or were too foreshortened to provide good rectified images.

F and M Old Main Rear Elevation with photos

F and M Old Main Rear Elevation with photos