I remind most of the responders to this discussion that the way of the world reacts much more to perceptions of reality than it does to reality itself.
Stephen
I personally love to see GIS'ers go to the field to stake out property corners based on their "accurately compiled metadata information". I wonder what the fatality rate would be? If us surveyors get some rough property owners pull guns on us, imagine what these office monkeys are going to do with farmer John when they tell him his 100 + year old fence is wrong because their stake out is 10+ ft inside the fence. I'd give one of my nuts to see how that one played out.
Good morning all. This is a GREAT topic, and I actually hesitated a day or so before replying just to make sure I got my thoughts in order.
I am a GIS professional, and I manage the GIS effort and land survey program at a very busy regional airport. I've been in this business almost 30 years, mainly on the Federal (Corps of Engineers) side, and I started back when what we think of today as 'GIS' was done manually - the HP-41 was our IT backbone ;-). Back in those days the US Army didn't have GIS professionals, we were trained as 'topographers' and the term had a broad definition. We were trained in geodetic and topographic survey (although we were not surveyors), aerial photograph analysis (although we were not photo analysts), geology (although we were not geologists), hydrology (although we were not... well, you get the idea), soils science, forestry and land cover analysis and cartography. The end product of all of this training was an individual who had a broad understanding of earth sciences and how to apply the unique contributions of each of these disciplines to the problem at hand.
As GIS systems like ArcGIS matured the Army made a quick transition to away from traditional topographic analysis to computer-based GIS. These systems(ArcGIS, ERDAS Imagine) allowed us to crank out more products in less time, but we quickly found that our young soldiers were no longer being trained as multi-disciplined thinkers. Gone were the analytical skills, replaced instead by IT system management tasks. As part of this transition all consideration of the unique contribution of geodetic and topographic survey to the GIS mission was lost. Military grade GPS positioning was viewed as the solution to all problems, and surveying as a military discipline died a slow and painful death.
I carried my topographers mindset into the private sector. In my first few jobs away from the Federal side I was surprised and disappointed at how undisciplined the GIS field was when it came to spatial accuracy. Most GIS personnel did not understand the underlying issues related to spatial accuracy - they simply accepted the data on face value and applied no critical analysis to its accuracy and origin. To be fair, an enterprise GIS system needs a LOT of data to be effective, and quite often spatial accuracy is less important than attribute accuracy. Since data development is the single biggest cost in any GIS program the acceptance and use of bulk data from third party sources has become an accepted practice. The problem is, there are no accepted GIS standards for spatial data quality. I can't look at data in a GIS layer (data table or metadata) and understand its accuracy based on GIS industry standard accuracy values - there are none.
I view surveying and GIS as complimentary disciplines with a lot of overlap. GIS personnel talk a lot about spatial data, but surveyors own the concept and definition of spatial accuracy from both a professional and legal perspective. Accepted survey practices, standards and technologies are the keys to GIS data spatial accuracy. My organization makes heavy use of RTK systems, both for survey and high accuracy data collection. These RTK systems have revolutionized data collection on the airport and we no longer accept mapping or consumer grade GPS data into our spatial data framework. The key here is that every data point we collect is tied back to a precise horizontal and vertical control network, either locally adjusted State Plane or our own local coordinate system. From this highly accurate data framework we extend our data accuracy assessments and adjust all third party and/or CAD data to this framework.
In the US the GIS world is badly fractured and often at odds with itself. The discipline is poorly defined. Some want it to migrate to the IT arena where web mapping to undefined accuracy standards will prevail (as one observant civil engineer commented at a recent FAA GIS confernce, "There's too damned much IS in GIS these days"). Others want it to remain a simple mapping discipline, content with data that is +/- 100' and judged more for its eye appeal than it's accuracy. This lack of standards keeps GIS from being accepted as a serious profession (and it seems a number of earlier posters have recognized this).
This is where we need your help! As GIS applications become more accessible and easier to use the perception grows that GIS systems offer up data at survey levels of accuracy. Blame GPS, blame sloppy data standards, blame the propaganda put out by the GIS application developers. Whatever, the perception is there and it is growing. Surveyors need to get out ahead of the discussion of spatial data accuracy standards and make it clear that spatial accuracy is a complex issue with legal implications and this issue is not addressed in current GIS data standards.
The benefit for the GIS profession is that your efforts will force us to finally sit down and develop an accepted set of industry-wide standards for spatial data accuracy. We need legally defined data accuracy standards that are tied back to survey accuracy standards. The surveying profession has the power to force us to get our own house in order and better define ourselves as a profession.
This is clearly a win-win for all parties!
Kudos, that awas an elegant and amazingly on point message, I tip my hat to you for taking the time to put this message out in the universe and to reach out honestly and respectfully to the surveying community.
