Sunday, February 7, 2010

GCNP river boundary 1 (edited 7/11/10)

One of the reasons for the Grand Canyon National Park Enlargement Act of 1975 was to fold several designations (e.g. Monument, Recreation Area) into the Park, and to consolidate administration of much of the federal land covering the Canyon. In particular, it seemed important to have a single administration over the Colorado River through the Canyon, and therefore set the Park "Boundary on South Bank of Colorado River (River Mile 164.8 to 273.1)". This formalized the unifying of the rules and bureaucracy that river traffic had to deal with, and to insure that Wilderness designation of GCNP (as called for in the Enlargement Act) would include the entire river. As the conference report said, the final bill provides that "all lands--including the entire river from the mouth of the Paria to the headwaters of Lake Mead--within the revised park boundaries to be studied for possible designation as wilderness". 

The USGS quadrangles that map the Grand Canyon have been produced and revised at different times. Most of the quads that cover the river from 164.8 to 273.1 (along the north edge of the Hualapai Reservation) were drawn before the 1975 Act was passed, and contain a variety of anachronisms arising from the variety of actions affecting the governance of Grand Canyon. Only from river mile 164.8 to 173.5 were the quads--for Gateway Rapids and Fern Glen Canyon--revised after 1975 to show the correct boundary.

The USGS quads are the basis for the very best map guide to running the Colorado through the Canyon, "Guide to the Colorado River in the Grand Canyon, Lees Ferry to South Cove" by Tom Martin and Duwain Whitis, 2004 (followed by several editions), see In the interest of (after 35 years) providing accuracy in the matter of the GCNP boundary, I have undertaken to update the relevant quads.

There are a number of different changes.
The center line, which separates Mohave and Coconino counties upstream of river mile 222, continues on downstream and needs to be removed.
The GCNP boundary needs to be shown on the south bank at the edge of the river surface, and on the correct rim on part of the north side.
On some maps, there is pink or brown stippling left over from some of the pre-1975 jurisdictions, e.g., the (second) Grand Canyon National Monument. It needs to be removed, and the river color or contours restored. 
Various words --"indefinite", "Indian reservation boundary", "national park boundary", "Lake Mead National Recreation Area" -- are inappropriate or wrongly placed. 

Since this project would benefit from conscientious application -- to get the optimum use out of Photoshop Elements -- I am concentrating on this small bit of Grand Canyon history for a while and will use this blog to record what I am doing. In part, it will be a record of failures, as I try different tools to make the above changes. For instance, today:

I was working on Columbine Falls, 36113A8, river guide map 49, ~mile 270-3. Removing the unneeded center line was a matter of using a marquee tool or selection brush or lasso to select a piece of river, copy it, select a piece of center line and paste-into-selection. Worked fine, covering the line with the mottled blue pixels. Except for the selection brush, which did not result in a paste.

I spent some time trying to remove some of the unneeded black letters, which  required conversion to RGB. The background eraser left a checkboard with gray. The paint bucket got closer to the white background, but was not good enough either. The trick here is that contour lines run "under" the letters and have to be drawn in. Next time.

No comments:

Post a Comment