![metes and bounds system metes and bounds system](https://lehnerer.arch.ethz.ch/wp-content/uploads/2013/09/Georgia-Headright_Late-MB-Plot-1024x783.jpg)
When we analyzed the distribution of our trees, we learned that red maples tend to grow on south facing slopes, while sugar maples tend to grow on north facing slopes. For example, we have used GPS to collect where trees are in addition to the species and size of the trunk. The need for survey grade GPS devices is not typically needed for research at Powdermill, as one to three meters of accuracy is usually good enough for most ecological and field biology research.īy collecting research data with geographic information collected from GPS, we can analyze ecological phenomena in space, which allows us to discover much more about plant and animal communities. We no longer use the top row of devices as the devices on the bottom row are newer technology that vastly outperform the older devices. At Powdermill, we use mapping grade GPS devices most often, as represented by the four devices on the right in the image above, but we also use recreational GPS devices and GPS-enabled mobile devices, which are the four devices on the left. The above image shows the different devices the GIS Lab has used over the years. More sophisticated GPS devices for mapping and surveying are not typically found in stores and must be ordered from specialty vendors. Other recreational GPS devices, such as Garmin devices, are fairly affordable and can be found at sporting goods stores. If your smartphone has GPS on it, as most do, that is considered a recreational grade GPS device. There are many different types of GPS devices and they are generally categorized into three accuracy levels: recreational grade (accurate from 3 to within 10 meters), mapping grade (0.5 to 3 meters), or survey grade (1 millimeter to 0.5 meters).
![metes and bounds system metes and bounds system](https://tngenweb.org/tnland/metes-2.gif)
Many GPS devices utilize all GNSS systems. GPS is also just one of a few other global navigation satellite systems (GNSS), as Russia, China, and the European Union all have operational systems as well. With just four satellites in view, the location of the GPS device can be determined by using a process called trilateration, which measures the distances between multiple satellites and the device on the ground (I’m not going to get into the technical math…).
![metes and bounds system metes and bounds system](https://i0.wp.com/www.probitytitle.com/wp-content/uploads/2016/02/oldlegal2.jpg)
It is a world-wide constellation of over 30 satellites that are constantly in orbit around the earth. However, you may be wondering, what exactly is GPS…and what does it actually stand for? The Global Positioning System (GPS) is operated by the US Air Force and has been around since 1978. To learn more about projects that use mobile apps and GPS, I recommend checking out the BirdSafe Pittsburgh program and our effort to map plastic waste. We can also couple GPS receivers with mobile apps to help us collect other non-spatial data. At Powdermill, we use these devices to quickly and efficiently record latitude, longitude, and altitude. The primary tool used today for collecting data in the field is a GPS receiver, as you might have guessed. But with today’s advances in technology, we use much different methods and tools to collect research data. At the GIS Lab at Powdermill Nature Reserve, we no longer use these techniques of old when mapping research data in the field. They also used the system of metes and bounds to describe the data they collected, typically for land ownership purposes. In my last post I talked about how surveyors and cartographers used chains and compasses to survey the land.