Stone/Masonry Wall Documentation:

Illustrated Specifications for Stone/Masonry Wall Documentation Using Rectified Photography and Plotting Technique

1.0 Objectives:To document and record the existing physical condition of the stone/masonry wall, including appearance, defects and damages, measurements, deformations and other physical attributes; and, to document and record the extent of the existing structure/s for restoration and preservation purposes (physical inventory).

2.0 Methodology: Measured Survey and Documentation of Existing Condition of the Wall in addition to Material Sampling and Laboratory Analyses.

3.0 Technique: Rectified Photography and Plotting This is an improvised technique to be employed in the technical documentation of existing structures in the absence of photogrammetric equipment.

4.0 Equipment/materials needed:

Digital camera or 35mm SLR camera with fixed macro lens; tripod/clamp pod, cable release, level attachment; color negative film of appropriate speed rating, and other necessary accessories

Video Camera and accessories

Flashlight and batteries

Desktop and/or Notebook PC with MS Windows OS, Photo editing, Imaging, AutoCAD and CD burning software; Flatbed Scanner, CD Writer/Rewriter, inkjet printer or plotter (Optional: Modem and Internet connection)

Nylon string (red) or Grid crosshair markers, concrete/copper nails, basic tools

Measuring Tape (metric), One-meter scale bar (metric), 10 and 20-centimeter scale bars for smaller objects, plumb bob, marking chalk

Metal scaffold and decking system

Safety goggles, gas mask, construction helmet, work gloves, harness or safety belt, rope, safety shoes, work clothes

Billboards

Fence, barricade bars

Paper, pen, pencil, clipboard, other supplies and miscellaneous materials needed

Clear plastic sheets, permanent marking pen (various colors)

Permanent marking pens (various colors)

(Optional equipment/instruments): Handheld GPS receiver, lensatic compass, transit (optional)

Instrument cases or boxes

Tent

Communication equipment (two-way radio, cellular phone)

5.0 Site Preparation: 5.1 This procedure requires prior cleaning of the wall surfaces, including removal of vegetation/biological growths

5.2 All field workers, technicians and project officers must wear safety gears and follow safety requirements

5.3 Coordinate work with local counterpart/s

5.4 Provide documentation scope of work and plans for field copy

5.5 Provide other documents, transport equipment and supplies needed

5.6 Construct fence, access, barricade bars, warning billboards and basic information

5.7 Install scaffolds and decking

5.8 Install nylon string grid rulers (vertical and horizontal), or grid markers5.9 Fix camera positions; photograph objective and log each take (Photo Key Map)6.0 Procedures (DIRECT PHOTOGRAPHY):

6.1 Install scale bar on the wall for every take/shot of picture.

6.2 Mount camera on the tripod or clamp pod. Measure a fixed distance from the wall surface to the film plane of the camera, so that each square frame formed by the string grids would fit fully on the viewfinder of the camera. Measure this distance and record it. Use this distance measurement for all framed shots. Mount level fixture into the cameras accessory shoe, and level the camera.

6.3 Record each film frame number on the grid wall elevation reference drawing or photo key map.

6.4 Process color negative films and print photographs on 5R format or larger (for SLR camera with macro lens).

6.5 Transfer digital photograph files to computer with professional photo editing software. Process photographs using uniform settings and scale (pre-formatted). Emphasis is given on balanced brightness and contrast for all photographs, so that the string grid lines and stone details could be visually legible.

6.6 Prepare standard Photo editing grid template based on scale bars; prepare grid templates for standard AutoCAD drawing sheet sizes that match the photo editing grid template. Use these as fixed working file templates for respective file types.

6.7 Open raster image file of each grid square in AutoCAD. Then trace all attributes of the wall surface so that the raster image can now be converted to vector image of that grid square. Repeat this process on each grid square, and stitch the image squares together to form a complete image of the subject structure in vector image file. A digital map of the structure for records and technical studies is now produced.

6.8 Produce a hardcopy of the vector image of the structure in a convenient scale for file storage and reference document. Produce the same on CD copies for file storage and information transportability.

7.0 Procedures (MANUAL TRACING):

7.1 Install cross-hair markers

7.2 Place and secure clear plastic sheet on wall surface to be traced

7.3 Trace all wall attributes (map), including the crosshair markers on plastic sheet using permanent marking pens (color coding for different attributes preferred)

7.4 Index and record each traced frame number both on the grid wall elevation reference drawing/key map and the plastic sheet

7.5 Place and stretch traced frame on a white board with grid module. 7.6 Photograph each traced frame using a uniform setup with a 35MM SLR camera with macro objective lens, or a digital camera with at least 2-megapixel resolution. 7.7 Process negative film and print photographs, and scan prints to convert photo frames into digital images (for SLR camera with macro lens). 7.8 Transfer digital photograph files to computer with professional photo editing software. Process photographs using uniform settings and scale (pre-formatted). Emphasis is given on balanced brightness and contrast for all photographs, so that the string grid lines and stone details could be visually legible.

6.6 Prepare standard Photo editing grid template based on scale bars; prepare grid templates for standard AutoCAD drawing sheet sizes that match the photo editing grid template. Use these as fixed working file templates for respective file types.

6.7 Open raster image file of each grid square in AutoCAD. Then trace all attributes of the wall surface so that the raster image can now be converted to vector image of that grid square. Repeat this process on each grid square, and stitch the image squares together to form a complete image of the subject structure in vector image file. A digital map of the structure for records and technical studies is now produced.

6.8 Produce a hardcopy of the vector image of the structure in a convenient scale for file storage and reference document. Produce the same on CD copies for file storage and information transportability.

8.0 SCALED MODEL/PHOTOGRAPHS/GRAPHIC ILLUSTRATIONS PRODUCTION

8.1 Scaled model/photographs/graphic illustrations production is very useful for site interpretation and technical studies

8.2 Produce reproductions in convenient scale/s for appropriate purposes

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