Scott T. Ralston

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GIS (Geographic Information Systems)

One of my big personal as well as professional interests is in GIS. This goes hand in hand with my first major interest which is wildlife management. Some of you may ask, what is GIS? GIS stands for geographic information systems. Basically it is a method of creating digital maps. In the simplest form it is like taking transparent sheets, each with different map features such as roads, cities, landmarks etc. and laying them over top of each other. GIS is used to make most of the maps you see today. GIS is more than a mapping tool. You can also create new information such as mapping landscape features off of aerial or satellite photography. You can create models by combining multiple layers and mathematically multiplying or adding them together. This kind of information has major uses in biological fields and habitat management. GIS also calculates length or area of lines or polygons you draw making it usefully in planning or reporting. Any information that has a spatial attributes can be done in GIS. GIS can use information in points, lines, polygons or raster's (images) and store information about each of the objects and locations.

I am almost entirely self tough in GIS and have had very little formal training. However, I am now training other people. There are some things you just have a knack for and I guess this is it for me. Although I like my job I am not in a permanent position. If there is someone out there that is looking for an employee for a GIS and wildlife/habitat oriented job I keep my options open. Feel free to look at my resume and send me a note.

These are some tutorials I have developed for training others in GIS. You are welcome to use them if you find information in them that helps you in your work or pass the link on to others that may find it helpful.

ArcGIS Basic Training

How to install ArcGIS 9.2

How to use a Trimble GeoXT GPS (or PDA with GPS) with ArcPad

Aerial Photography & Flight Navigation - This is very specific to the system I set up for the USFWS for their easement flights. Read below for the application of this system. If you are looking to setup a similar system the basic outline may give you some ideas.

These are some presentations I have given for GIS in Wildlife Management. Use it if you would like but just give credit where credit is due.

GIS for Wildlife Management

Geospatial Technology for Easement FLights - USFWS Devils Lake

Spring Aerial Photo Comparison - USFWS Devils Lake

My major GIS projects:

NDSU Masters Research

I was first introduced to GIS during my graduate program at NDSU. The research project that I took on was identifying how much cattail there was in the prairie pothole region of North Dakota. The basic reason for this research was for the USDA Wildlife Services agency. They assist farmers with animals that damage crops. Large numbers of blackbirds eat sunflowers causing financial loss. Large flocks of blackbirds roost in cattail marshes in or near fields during the night and depredate nearby fields during the day. One solution to the problem is spraying cattail to kill it, thereby removing places for blackbirds to roost. The major question that arose was how much cattail is being removed and is it too much since cattail provides important habitat for non-targets species such as deer and pheasants? The USDA knows how much they spray so they just need to know the total available. I sampled 480 square miles in the prairie pothole region of ND. It would have taken years to survey all that land conventionally. I looked into different options and found GIS to be the best solution. I took color infrared photography of all sample sites. I scanned the photos and georeferenced them which basically means letting the computer know where the photo belongs on the earths surface. From there I used spatial analysis where I tell the computer what to look for in the photos and it searches all the images and maps out that feature. Using color infrared photography, cattail shows up as a distinct color and texture so it is fairly east to identify. The GIS reports the acres of cattail in the sample sites which can then be extrapolated to the entire landscape. Bottom line was less than 1% of the total cattail in ND was being sprayed which is unlikely to have any major non-target effects. In addition to cattail I also mapped out the entire wetland basins and individual characteristic of each to get a profile of wetlands in the prairie pothole region. In total I mapped over 16,000 wetlands. I could not have done the project without GIS.

More information about my masters research

Masters Thesis

Masters defense presentation

Published paper on the research

Unpublished followup paper on Wetland Mapping

US Fish and Wildlife Service

Wetland Mapping

After my masters program I fell into a job that was a perfect follow up to the GIS wetland mapping skills I just learned. The USFWS in Devils Lake deals with more wetland easement issues than any other station in the country. A wetland easement is where a landowner sold the rights of the wetlands on their property to the government for 60%-75% of the current market value of the land. These are perpetual contracts so it is paid for once and the wetland is protected from draining or filling forever. The hunting and access rights remain with the landowner and the wetlands can be cropped if naturally dry. Most of these easements were sold in the 1960's so over time people forgot about the easement on their land or with change of ownership the new owner was not made aware of the easement. Because of this as well as some intentional deviance, wetlands are often drained or filled resulting in enforcement actions by federal officers. My job was to map wetlands on these easements. Originally the easement contract stated all wetlands on the property were protected therefore no map of the wetlands were needed. A court case in the 1990's ruled that only the number acres determined during the original purchase could be protected. The methods of determining acres were rudimentary and more of a visual estimate during the easement acquisitions. In some cases more acres were actually paid for than there are wetland acres on the land so there is no problem determining what has protection. Problems come in when there are more wetland acres on the land than what were paid for. In that case it is important to identify which wetlands on the property are covered under the easement and therefore protected from drainage. The conventional method of mapping was laying a piece of mylar (semi transparent paper) over a black and white photo and trace the wetlands with a pencil. Then a grid of dots was laid over the wetland drawing the the number of dots inside the wetland line were counted and multiplied by a predetermined number to give you the acres. This was very crude and inaccurate. Identifying wetlands on an old black and white image was tough. If it happened to be a dry image many wetlands didn't show up so were not mapped. Some features were misidentified so rock piles or grassy hilltops were often circled as wetlands. The acres estimate were often very far off from the original. When I arrived on the job I flipped everything upside down. Using GIS I converted every aerial photo into a digital image by scanning it. They were then georeferenced so the computer knew where the image belonged on earth. For all locations we had approximately one aerial photo from each decade dating back to the 1950's. Most are black and while and were mid summer photography but we had some color infrared spring images from the 1980's National Wetlands Inventory project. Since 2003 the USDA Farm Service Agency has been taking color digital aerial photos every summer which are freely available as well. In most cases we had about 10 years worth of imagery to look at to identify wetlands and determine their full size, shape and area. In addition to aerial photos I also brought in digital elevation models from the USGS which gives a 3d view of the land so you can see depressions vs. hilltops. The NRCS also has soils maps which I used as well to identify areas with hydric soils. We also contracted Pro-West and associates out of Walker MN to do high quality early spring digital color photography in 2006 which gave us images of wetlands at potentially their fullest point just as the snow melts. Temporary wetlands which may only hold water for less than a month in the spring showed up well in the spring imagery. With all these tools at our disposal we were much more accurate and confident in the wetland mapping ability. This was a huge project mapping thousands of square miles of wetlands. Since the wetland maps I produced had legal implications, quality was of the utmost importance. I trained our staff in these techniques and soon started spreading the methods to other field stations. I have moved on to another job since the position I had was a term position and funding was cut after 2 years due to government budget cuts. However the methods are still being used and I am still providing support where needed. The many of the wetland maps are nearing completion for easements in the DL district and once finalized will be a great tool to identify what is protected so the enforcement officers can monitor them and the landowners can know what not to drain.

Aerial Photography & Plane Navigation

During my USFWS mapping position I helped with many aspects of the conservation easement enforcement. One of the tasks I participated in was easement flights. The common way easements are monitored for potential violations is by flying an airplane in transects over all easements and record a drainage ditch or other violation type. This is easier said than done. The method used was to take a paper map with roads town and other general features as well as a layer showing all easements on it and use that to keep track of where you are. For those that have ever flown over rural ND you will know it is all farm land laid out in a giant grid and everything starts to look the same. You start from a know location on the map and count section lines (1 mile grids) as you fly over the land. After hours in the plane and concentrating on looking out for violations as you fly at about 150 mph it is easy to loose your spot. I figured there must be an easier way. I attached a GPS unit to my laptop, loaded GIS maps onto it with all the easements and other features such as road and towns that I needed and brought it in the plane. Navigation was simple. You could concentrate on looking out the window for violations and the computer kept track of where you are. When I spotted a violation on an easement I marked the GPS point on the computer screen with a short note of what I saw. The second phase of the easement flights was photographing the violation for evidence. After all violations were recorded a second flight was done to return to all the spots, fly in circles around the location and take pictures by pointing the camera out the window. If you though navigation was hard before try doing it while flying from point to point instead of straight transects and getting totally mixed up as you come out of 4 and a half turns. Besides being lost the constant circling while looking though a camera lens isn't for the weak stomach. The previous navigation method using the laptop with GIS maps and a GPS worked great again for navigating point to point. I just played connect the dots with all the points marked on my screen and we had a flight line for the pilot to follow. As for photography I decided to try a belly mount system. We rigged up a camera mount that pointed a digital camera straight down through a small home in the floor of the plane. This had several advantages. First we just had to fly straight over top of the violation, snap a photo as we passed and move on to the next one. This prevented the circling which saved a lot of time, sickness and navigation issues. The vertical picture also provided and image we could use in GIS. The photo can be overlayed against other aerial images to compare wetland changes over time or to see it the wetlands impacted by a ditching the picture were identified as having protection by the wetland maps made earlier. Oblique images out the window would be distorted as the farther an object is from you the smaller it appears and side angles produce more visual obstructions due to objects and shadows. Since the camera was digital it could be hooked to the laptop also which provided virtually unlimited storage space and the shutter could be released by clicking on the computer screen so you didn't have to be in direct contact with the camera. To see through he viewfinder of the camera I mounted a web cam on the eyepiece of the camera so I could see from the laptop as well. With the trial run being successful I wrote a proposal to get funding for a full set of the needed equipment for the Service airplanes and went to Denver to present the idea to the regional director. It was a hit so I went through major refinements of the system and was able to purchase the aerial photography and navigation equipment and set it up. I used tablet laptops so users could just tap on the map on their screen to mark a violation instead of fumbling with a touch pad mouse. I used a 12 megapixel camera for very high resolution. I also went away from conventional photography and used a 14mm lens. This is a very wide angel lens which allowed us to fly much lower (<2,000 feet) than conventional lens and have a lot less haze. We often fly in the spring and fall when cloudy days are common. By flying low you can often fly under the clouds and still get your job done instead of conventional methods that require 10,000 feet or more for the same image. The only problem is the objects farther on the outside of the image (edge of the lens) are taken at a steep angle so you may get more of a side shot of a building than a straight down shot. This is not a problem for what we do since we are interested in features on the flat ground itself. We also take the picture with plenty of overlap on the edges so the subject is in the middle. I conducted training for all ND, SD & some MN field stations on this new equipment and most stations are adopting the methods after they saw it in action. The USFWS HAPET office in Bismarck, ND also adopted the equipment and general methods with some adaptations to use it their biological surveys. The web cam I originally used is replaced by a better quality video system that is designed specifically for mounting to the camera viewfinder.

Camp Wilderness Mapping

I was in boy scouts growing up and during college I spend my summers working at a boy scout camp that I attended as a kid. Those were some of the best summers of my life. While working there I spend some of the time maintaining hiking trails. The camp has many trails and if you aren't careful in the backwoods areas it is easy to get mixed up where you are going. Most of the maps the camp had were old and trails had changed or been added or removed. I was an experienced scout and familiar with he area and even I had got lost by trying to follow one of the maps once. Once I got into GIS I decided to take on a camp re-mapping project. I used a PDA with ArcPad on it (mobil GIS mapping program) an a GPS unit attached to it. and travels roads, trails and campsites in camp. I also borrowed some aerial photos the camp ranger had gotten from the forest service. Using the GPS data in conjunction with the aerial photos I scanned and georeferenced I was able to produce much better maps of camp. These amps can also be easily updated and reproduced as features change in camp.

Online posting of the camp mapping project

GIS Links

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