South Texas Land Surveyor

The Great American Road Trip

As we approach this Memorial Day weekend with all of its activities and travel, it seems appropriate to take a look back at some of the history of road travel in this great country.  xyHt recently recalled a brief portion of that history in Highway Anniversaries - A Look Back and Ahead.  Karen Cummings notes in her article that we are approaching the 60th anniversary of the interstate highway system, created by President Dwight D. Eisenhower's signing of the Federal-Aid Highway Act on June 29, 1956.  We also just passed (on April 30th) the 90th anniversary of the famous Route 66, connecting Chicago and Los Angeles.  With the ever-increasing number of vehicles on the roads, construction and maintenance won't be slowing down anytime soon, so enjoy this nostalgic look back (and a little look forward) as you pack up your picnic for the holiday weekend!

Surveying Traditions

In his recent article on the xyHt Surveyor's Field Notes, author Scott Martin takes a trip back through some surveying history.  Ever used a theodolite?  Measured distances on a slope with a chain and plumb bob?  Seen the artwork created in map format by those who were adept with pen and ink?  (If you have never visited their office in Austin, a trip to the General Land Office is in order to see some excellent examples of the latter.)  Whether or not you have surveying experience in your past, you'll enjoy Scott's perspective on the impact that new technology is having on the surveying profession - not to mention everything else!  Among other distinguished duties, Scott currently serves with the NGS as California Geodetic Coordinator.  Enjoy the trip down memory lane!  See the full article here.

Merry Christmas, and a Happy New Year!

As yet another year comes rapidly to a close, we sincerely thank all of our customers for their patronage, and our vendors for supporting our work.  May God continue His blessings in the new year.  Merry Christmas!

GIS and Humanitarianism

In today's connected world it's no secret that there is a wealth of information available at our fingertips, but as GeoDataPoint Editor Valerie King points out in her article "Giving Back with GIS", geographic information systems technology is being applied to less conventional causes.  She references how the MapAction charity used GIS to help coordinate the response to Nepal's 7.8-magnitude earthquake (see the image in this post), how the Department of Health and Human Services offers a GIS tool to help with health disaster readiness, and the EPA's "environmental justice screening and mapping tool" to identify locations with elevated environmental issues.  The technology behind these tools is nothing new, but the new applications of this technology showcase the power of GIS.  See Valerie's full article here, including links to the various organizations mentioned.

What's a Datum, and Why Does it Matter?

In the context of last month's post regarding David Doyle's article, "Why Doesn't My Centimeter Match Your Centimeter?", guest columnist Denis Parrot expands on that issue by addressing the concept of the survey datum.  While often overlooked by the novice - and sometimes by the professional - the datum that is referenced for any particular survey or collection of field data is critical for determining how well that data set will match up with any other survey.

For example, this image shows what can happen when map imagery is referenced to one datum while collected street data references a different datum.

As is evident, consistent use of the correct datum is critical for good results when combining data from various sources.  Parrot goes on to describe differences between some datums or "reference systems".  He emphasizes how important it is to answer the question, "But compared with what?"  Data within any given survey set may be very precise, but how accurate is that survey when compared to another data set from another source?  This applies to anyone using GNSS data, from the professional surveyor providing data to a client, to the farmer collecting his own topographic data, to the GIS user combining data from multiple sources.

For details, see the full GPS World article here:  "Precise GNSS Positioning — but Compared with What?"

Why Doesn't My Centimeter Match Your Centimeter?

In this GPS World article by the same name as this blog post, author David Doyle shares some of the expertise gained with 40+ years of service with the National Geodetic Survey.  He addresses a common issue with the accuracy of modern GNSS survey techniques.  With all of the amazingly accurate technology that is at our disposal for collecting location information to the nearest centimeter, we still commonly see the scenario in which "I got a cm, and you got a cm, but our centimeters differ by a meter."  If the systems used for data collection are so capable, then all positional data should fit nicely with no discrepancies... but every surveyor knows this simply isn't the case.  One example that I see regularly can be found in Google Earth, which is an incredibly useful tool, but as you review the latest available aerial imagery you may find offsets in the center stripes of highways where one image is improperly seamed to the next.  This calls into question the accuracy of the entire system.  Doyle reminds us of an important concept:  the number of digits to the right of a decimal point has nothing to do with accuracy.  So as data collection technology becomes more accurate and more accessible to the masses, education on how to use it correctly is a must.

GPS snow plow tracking

Here's an interesting application for GPS asset tracking that thankfully doesn't apply to us here in south-central Texas, at least not very often.  In this article GPS World reports about the system that many major cities up north are using to track their snow plows, and then provide mapping information to residents showing which streets have been recently plowed.

So glad this isn't an issue where we live!  Even if we had the snow plow map at our disposal, we'd probably call it a "snow day" and track the plows from the comfort of our own homes.  Just one of the many perks of living in Texas.

Glowing Orbs & GPS Signals

For all of you satellite buffs who like anything that has to do with GPS, you'll want to explore the creation of designer Timo Arnall.  As part of a research project at the Oslo School of Architecture and Design, he has created lamps that change brightness depending on the strength of GPS signals.  Arnall said, “Satellite Lamps show that GPS is not a seamless blanket of efficient positioning technology; it is a negotiation between radio waves, earth-orbit geometry and the urban environment. GPS is a truly impressive technology, but it also has inherent seams and edges.”  For more details, visit the article at GPS World.

Merry Christmas! ... and Thoughts on "Boundary Surveying"

As we approach the end of another busy year, we sincerely thank our clients for the opportunities to provide you with surveying and engineering services, and we wish each and every one of you a Merry Christmas!  May the new year 2015 be another blessed and mutually prosperous year for us all.

A significant portion of our business revolves around the typical "boundary survey", but in many ways there is nothing typical about it, and each survey is unique due to the specific requirements of the client.  In his article entitled "Traversing The Law: Do Surveyors Commit Consumer Fraud?", POB's Jefferey Lucas differentiates between a math stakeout and a boundary retracement.  The distinction between the two is important for both surveyors and clientele to understand.

Until next time - happy surveying!

Gratitude is ...

Gratitude:  n.  1. the quality or feeling of thankfulness or appreciation; the state of being grateful.

Once again the season has arrived wherein we are reminded - and unfortunately, we do need to be reminded - of the abundance that most of us tend to take for granted:  food, clothing, shelter, productive work, and relationships.  As we regularly experience these blessings, it becomes easy to overlook all of the good and focus instead on the day's troubles.  We are also reminded to reach out and share a portion of our abundance with those who through no fault of their own are in need of assistance.

From the perspective of our company, we are indeed grateful for the continued patronage of our fine clientele, and we wish for the continued success of your personal and commercial ventures.  Thank you for allowing our firm the opportunity to provide surveying and engineering services.