Redefined Horizons Blog

In early January of 2012, San Joaquin County released updated filed survey map index data for both corner records and filed survey maps. You can download those files using the link in the box above entitled “San Joaquin County Data”. The data was released in ESRI Shapefile format. The shapefiles contain not only the footprint of new maps, but also the footprint of historical maps. You can download a zip file with the latest San Joaquin County data for the filed survey map index which was released on January 7, 2012.

I need to complete the following tasks before I can release updated CAD drawings of the digital filed survey map index that correspond to this latest shapefile release:

• Clean-up data in the shapefiles before import into CAD.
• Create map labels for the new map footprints.
• Determine current gap between digital filed survey map index and latest filed survey maps.
• Download and zip copies of recently filed maps included in the index since the last update.

I hope to complete these tasks by the end of middle of March.

The Sunburned Surveyor

Lathrop High School ACE Team

Last Wednesday evening I gave  group of high school students a crash course in 3D modeling using SketchUp. It was an interesting demo, as I hadn’t used SketchUp for a long time. The students are required to use SketchUp to prepare a 3D model and rendering of the monument they are designing. The students are designing the monument to represent the City of Sacramento as part of the Sacramento ACE design competition.

The American Surveyor – Footsteps Column

I wrapped up the article graphics for two (2) of my latest articles on boundary surveying that will be published in the Footsteps column of  The American  Surveyor Magazine. The graphics for my article on Best Practices for Very Large Boundary Surveys were completed on Friday. Today I completed the graphics for an article discussing the court case Fripps versus Walters. I’ll start working on the graphics for my article Determining Property Corner History tomorrow. The first of these 3 articles, Best Practices for Very Large Boundary Surveys, should be published in the February issue of the American Surveyor.

CCVGPG Working Groups

I started work today on the web pages for the working groups of the California Central Valley Geospatial Professionals Group. I hope to have the the web pages up this week.

The Sunburned Surveyor

I recently discovered a new blog by a fellow land surveyor. I haven’t read all of the blog posts in detail, but I plan on looking at them more closely. The blog, entitled The Surveyor’s Point, is written by Paul Goebel.

The Sunburned Surveyor

I’ve completed my first draft of my second contribution to the new edition of the book “Land Surveys: A Guide for Lawyers and Other Professionals”. This second contribution is an article on aerial photography. The article is entitled “Aerial Photography in the Land Development Process: Understanding the Basics and the Land Surveyor’s Role”.

The article was reviewed in a gracious gesture by Terry Hayden, a long time friend and working partner of KSN. Terry Hayden is owner of the photogrammetry company Aerial Photomapping, located in Clovis, California. The article also went through a review by Kris Nehmer, the survey department manager at KSN. I’ll be integrating comments from both reviewers this weekend. I hope to make my final submittal of the article to the editor on Monday.

The Sunburned Surveyor

The San Joaquin County Historical Society has scanned their collection of historic tax assessor plats and made them available online. I’ve used the plats extensively for chain-of-title research related to riparian water rights within the County.

Hopefully they will be useful for other land surveyors and researchers working in San Joaquin County.

The Sunburned Surveyor

The San Joaquin County Historical Society has a cool blog post about one of the Civil Engineers that surveyed a majority of San Joaquin County. The engineer’s name was Henry Budd. I often follow his footsteps in my day job as a land surveyor at KSN. The blog post also talks about a large map produced by Budd that is now in the possession of the historical society.

The Sunburned Surveyor

My latest article for the Footsteps Column in the American Surveyor Magazine has been published. This article discusses changes to the 2009 BLM Manual of Surveying Instructions.

The Sunburned Surveyor

Its time to give a quick update on some of the things I’ve been working on. Now that I’ve arranged the first meeting of the California Central Valley Geospatial Professionals Group and helped arrange the annual meeting of the OSGeo California Chapter, I’ve turned my attention to some writing tasks.

The American Bar Association is getting ready to publish a revised addition on their book entitled “Land Surveys: A Guide for Lawyers and Other Professionals“. I’m contributing two (2) chapters to the book. The first one is “Coordinating Land Surveys In Multiple Jurisdictions”. The second is “Aerial Photography in the Land Development Process: Understanding the Basics and the Land Surveyor’s Role”. I submitted the first chapter to the publisher this week. The second chapter should be done soon. The book will be published next year.

I was happy to contribute. I hope my chapters help flesh out the book.

The Sunburned Surveyor

The October 2010 issue of Inside GNSS Magazine had an article entitled “When GNSS Goes Blind”. The article discussed the use of limited GNSS information and features extracted from a camera to navigate. The concept being that a camera mounted on a vehicle could be used to supplement GNSS signals in poor GNSS environments like forests or urban canyons.

The first few paragraphs of the article do a great job introducing the concepts that are later explained in greater detail (with algorithms for the math fans). I’ll see if I can include an even shorter summary here, but you should definitely read the first part of the article. Here is the summary:

1. One or two GNSS satellites are often “visible” even in poor GNSS environments.
2. Carrier phase measurements to these satellites can be used to determine the position of features extracted from images from a single camera lens.
3. These features can then be used to navigate when there are no GNSS signals.
4. The effectiveness of using stereo vision (a camera with two lenses, or two cameras) to position features extracted from images is related to the distance between the two lenses. The greater this distance, the more effective the stereo vision. This makes stereo vision a poor GNSS navigation supplement choice for small devices like mini unmanned aerial vehicles and hand held devices.
5. A single camera can be used to mimic, in a way, stereo vision, by taking two images with a single lens from different locations at different times. The GNSS measurements to one or two satellites can then be used to determine the distance between the camera positions for the two images. This creates what the article calls a “synthetic baseline” similar to the actual baseline between the two lenses in a stereo vision system.

Check the article out. It presents a cool concept.

The Sunburned Surveyor

The April 2011 issue of Point of Beginning Magazine has an article on evaluating property corner monument history entitled “What Lies Beneath”. I’ve always called the sequential changes to a property corner monument as “monument pedigree”. In this article, the same concept is called the “chain of history of monuments”. I like this term, and may adopt it myself. The article is only three (3) pages, and is worth reading. One of my favorite parts of the article is a diagram showing how different monuments were set at a road intersection as roads were raised and improved.

The Sunburned Surveyor