Attributes: How do you make a surveyor understand the importance of ALL the attributes, not just the X/Y/Z coordinates??

• GIS JANET says …

The survey community needs to understand that there are many different types of uses for GIS data and most involve much more information than the basic X/Y coordinates.

My quick answer to this question is that you make a surveyor understand the importance of all the attributes by thoroughly explaining what attributes represent and why they are so important. However, I have taken this approach before only to hear the comment, "Surveyors don't want to be involved with GIS because the data isn't accurate. Geospatial information needs a highly accurate set of X/Y coordinates in order to be represented in a GIS." And to that I say … not ALL geospatial information needs to be survey-quality to be recorded, displayed, and highlighted on a map to give you a true picture of information.

To prove that point, all you have to do is ask surveyors if they have ever used Google Earth. Most folks enter in an "attribute," like a house number or city/company name or zip code, and the software zooms them to an X/Y location. The viewer never really needs to see or use the X/Y coordinates. If coordinates were a must for finding a location, then Google Earth would need to reinvent its software to allow for this.

Like everything else, attributes come in all shapes and sizes; some are represented as text, others as numeric. But either way, their primary role is to further describe the features of the location point (X/Y). Some of the most common attributes are size, color, manufacturer, length, material, and condition.

Attributes are central to a GIS and are housed in the database, making GIS different from other software. It is the power of the attributes stored in the database (including the X/Y/Z coordinates) that draws the graphic you see on the computer monitor. And the reason the GIS can make so many different maps (thematic maps) from the same database is that the attribute selected can be highlighted or combined with other attributes. Each combination of selected attributes can eventually be drawn to play up or play down certain aspects of the story being told.

In February I attended the North Carolina Society of Surveyors Annual Convention. The luncheon keynote speaker was David Zilkoski from the National Geodetic Survey. His speech was accompanied by a highly graphical PowerPoint presentation, where almost every map displayed was created in a GIS. Did he need survey-quality X/Y coordinates to display his information to get his point across? No. Were his maps accurate and complete? Yes, because he was able to combine large-scale boundary maps with point locations that were drawn and labeled directly from his attribute database. He made his speaking points visually come alive by using selected attributes from this extensive GIS database.

The survey community needs to understand that there are many different types of uses for GIS data and most involve much more information than the basic X/Y coordinates. A map can be complete and accurate without X/Y/Z survey-quality coordinates. It all depends on the type and scale of the story you are trying to tell and which coordinates and attributes you need to use to communicate to your viewer.

The days of the GIS-surveyor tug-of-war are over. It's time we both agreed that data does not have to be survey quality to be a tremendous value. The value of the data is in the eye of the beholder, and the beholder could be you looking to find a special place somewhere on Earth.

• SURVEYOR RANDY says …

Surveyors aren't totally against attributes, we just like to include them on the face of the map, not embedded in a hard-to-find database.

My quick answer to this question is that you cannot make most surveyors do anything. Most surveyors tend to be too analytical, too opinionated, and too independent to be made to do much of anything. If you don't believe me, just ask county planning departments and county registers of deeds.

Seriously though, I believe surveyors understand that attributes can provide many of the details we like to know and understand as detail-oriented, accuracy-driven professionals. We also understand that these attributes are important, especially when it comes to accuracy, whether that accuracy is centimeters, feet, meters, or miles.

Our concern is that many members of the general public who use GIS may be limited in understanding the accuracy of various GIS data sets and may not have the expertise to uncover the metadata, if provided, that is associated with the data. If the person using the GIS is unable to access the metadata and/or doesn't understand the accuracies stated in the metadata, the GIS data can certainly be used inappropriately or incorrectly.

I, as a surveyor, do not require or expect all data that I generate or obtain from other sources to have "survey accuracy." The survey accuracy I need as a surveyor is the accuracy required by our licensing boards or other standards we certify to with our seals and signature. Not every single point or feature shown on a map or in a GIS can or should have an accuracy of one hundredth of a foot or one millimeter.

My fellow surveyors and I use GIS sites numerous times virtually every day. The GIS websites of municipalities, counties, and state government are lifelines to a wealth of information that we surveyors would be hard pressed to do without.

Also, the information shared by other entities, such as public utilities, is very beneficial when we are performing various types of surveys within their properties or easements.

Janet says that if coordinates were necessary to find a location, then Google Earth would need to reinvent its software. But that's not totally accurate. Google Earth includes latitudes and longitudes, which can be converted to actual grid coordinates using conversion software readily available on several internet sites. Surveyors aren't totally against attributes; we just like to include them on the face of the map, not embedded in a hard-to-find database.

Before the birth of GIS, surveyors surveyed and drafted maps that displayed many of the physical features that would be included on one or more layers of a GIS map of today. Those features were not mapped at the same accuracy as we map today, but they were amazingly accurate, considering the tools available during that period of our history. They also displayed much more information than the basic X/Y coordinates; in fact, I have never seen an X/Y coordinate on a historic map made a century or more ago.

Attributes may not be as central to a survey plat as they are to a GIS, but they are essential and are often required by general statute or local regulations. These legal and regulatory requirements tend to limit the creativity and flexibility of the surveyor to produce an artistic masterpiece instead of a clean, uncluttered "picture" of factual and accurate information.

While Janet and Randy may not see eye-to-eye on all surveying and GIS issues, they do work together on a daily basis, respect other's perspective and point of view, and attempt to "intersect" their professions whenever possible. Randy and Janet invite you to submit your questions to "Intersect." Contact them via email at intersect@mckimcreed.com or at 919.233.8091.

About the Authors

  • Janet Jackson, GISP
    Janet Jackson, GISP
    Janet is certified as a GIS professional and is president of INTERSECT, a GIS consulting firm.
  • Randy Rambeau, Sr., PLS
    Randy Rambeau, Sr., PLS
    Randy is a geomatics office manager with McKim & Creed, an engineering, surveying, and planning firm.

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