(Full-size of download: 4400x3200 pixels) |
Here's the Topo Map with the 0.1% tilt correction. It's possible the aspect ratio was unintentionally altered during scanning; many scanners then had mechanical parts that wore or grew sluggish.
(Full-size of download: 4600x4000 pixels) |
Now here's a good-resolution aerial or satellite photo (I had to stitch a few images together). I figured you wanted the North Yard and North Tower.
(Full-size of download: 7300x6000 pixels) |
Finally here's my transparent overlay of the satellite photo onto the Topo Map. You can try your own figures. Here's mine. I tilted the aerial composite 14.4% and enlarged it 187.5%. It's all subjective, unfortunately. This particular overlay matches some of the building street-level bases and is close to the curvature of Elm Street.
My overlay method has the aerial short of the north curb on Main and it means the Topo Map got wrong the location of the pergola and the masonry structures by the pool. I wonder if those structures were surveyed on a different day, or rendered from an aerial, and added in later, inadvertently getting it wrong. If my placement of the aerial photo on the Topo Map is correct, then I would go with where the aerial shows the pergola, bridge and North Tower.
There's a trade off that's appropriate for you working with your own set of figures. It would be nice to get the Topo Map to work but you have to be aware of where it's wrong.
Now if you only wanted a generalized map, then the Cutler Plat would do. In my 3D model, I found that sloping Main (beginning at the west edge of Houston and ending just before the bridge entrance) 3.2° worked. The usual slope is said to be 3°, probably rounded.
The Knott Lab 3D scan of the physical Plaza is the modern way to extract figures and angles. You would need a very robust computer just to open that model. It would take years to clean up the extraneous noise in the scan and reduce the file size for home use. So we're left with the 2D approach.