Navigation using UTM coordinate Maps

Introduction:

The previous lab from February had the students create maps based on UTM gridsthat had a navigation function using paces that were taken from a measured area. This data was then inserted into a map that would then be used for navigation in the field. Using these field maps in the area of study it was possible to use GPS and the created maps to find and collect points that were assigned to the group.

Area of Study:
The area of study is the Priory. The Priory is a UWEC returning student housing area for non traditional students. It was originally a priory for monks before it was re purposed for student housing. This is a residence hall that is set in 120 acres of woods that is inter-cut with semi moderated trails. Since this area is in the wilderness with a large area of woods it is easy to get lost and difficult to traverse.

Methods:
The original maps that were created in February were used to navigate the priory. before setting forth and collected the GPS coordinates onto a GPS device it was important to record the area that was hiked along the way. The GPS that was utilized has a function to switch from Lat and Long to UTM grid system. This was used to correspond to the maps that were originally created. It was at this point that we would have to find a way to prove we made it to the UTM points that were assigned to the group. This was accomplished by collecting a point in the GPS unit and by taking a picture that had location enabled. once the initial set up is completed the group decided to plot the assigned points onto the map to create a ease of access and navigation area. This was sort of a rudimentary navigation chart.

UTM Grid Map used (credit Rachel Hopps)

Once the initial set up was complete with the GPS unit and the map it was time to navigate to the points plotted. At the start up the group decided that it would be best to stick to areas that looked like they had a trail attached. This allowed the group to move from trail to point in a quick succession. However some points were located deep in the woods. to move quickly from point to point we jumped as fast as possible from point to point by going in as straight as lines as possible. This was difficult because of the heavy vegetation in some areas that forced the group to take drastically different directions in order to navigate the area which can be seen on the tracking data.

Collecting the first point with Rachel and Joseph

After the points were collected it was time to update the area in order to create a map. To do this we had to use the GPS number that was attached to the unit and the group number that was assigned in order to get the data. once the data was inserted into ArcGIS it was possible to see how well the group traversed the area.

One known problem that the group noticed is that the compass on the GPS was not the greatest for quick turn around. The compass is electronic and would take a few moments to adjust to the direction of the group. This made travel frustrating as the group would have to re adjust every 10 meters or so. Other sources of frustration came from the heavy amounts of vegetation and brambles about. The vegetation made travel difficult and with the brambles, sometimes painful. The map also did not contain some data that would be useful to the group. The data that would have been useful to the group would have been elevation data in the form of topographic maps since some of the points were in an elevated position this data would be useful and should not have been excluded

Tracking Path and collected coordinates

Results: 

For the majority of the experience we can see that the group made short work of the points with only a couple of instances where the point collected was difficult to traverse to. this is because the initial planning allowed the group to plan an approach as well as having a set job for each person. one person would be using the GPS unit for measuring the tracking and navigating with a compass, another would be using the UTM map to geed the coordinates that were needed to the GPS user and to count pace. The third and last person would be breaking the trail up for ease of travel and would take pictures and notes. By using a three person team it was possible to create a sort of oblong circle to collect all the points which were then inserted into ArcGIS

Conclusion: 

Collecting data in the field is the prime example of geography. Some agencies require field methods and the ability to create a accurate map and to use the GPS and UTM coordinate map created for a Area of study is invaluable for many companies and profiles. This area of study and map creation and field navigation is useful for surveying, search and rescue and many other applications. 

Processing UAS Data in Pix4D

Processing UAS data in Pix4D

The Pix4D software is a Drone Mapping Software for professional drone based mapping purely from images that are taken with an aerial mapping platform. It is possible to use the Pix4D software to create cutting edge results that include but are not limited to Thermal mapping and 3D mapping. It is a useful software that is used in a variety of industries including emergency response, agriculture, mining and real estate. It is a easy to use program that almost anyone can pick up and enjoy.

How to use Pix4D:

Before starting a project it is important to have a image acquisition plan. This is an important step to create keypoints. Key points are a characteristic point found in an image. When 2 key points on 2 different images are found to be the same they are called matched key points, each match Key point will produce a 3D point. The more points captured the more accurately 3D points will be computed. So a high overlap of images is required, at the very least 75% frontal overlap and 60% side overlap is needed. If the user is flying over a homogeneous area such as sand/snow or a uniform field like agriculture lands it is important to increase the overlap to the images by at least 85% frontal overlap and 70% side overlap. Flying higher will also improve the results as well as having accurate image geolocation available.  An available tool for use is rapid check, rapid check is used to verify the proper ares and coverage of a data collection. The Pix4D software is also able to process multiple flights. The pilot does need to make sure that each plan captures the images with enough overlap and that there is enough overlap between the 2 image acquisition plans under the same weather conditions. It is also important that the flight height should not be too different between the flights since this can change the spatial resolution.

In order to produce oblique images the type of data that we need to take is the GSD or Ground sampling distance. It is advised to create Ground Control Points (GCP) if no GCP are used than the scale and orientation constraints can be used. If neither GCPs or constraints are used the final result will have no scale, orientation and no absolute position information. This will make it impossible to use for measurements, overlay and comparison. Finally when the process runs through the Pix4D system we will get a quality report which will report the information computed during the process. This will give us information regarding how many points were acquired the amount of overlay obtained and a summary of the project which can have the AGD, and the amount of area covered.

Methods: 

To use the software we will have to import images that were captured with a UAV device. this could be a multi bladed copter or a fixed winged UAV. After the initail mission is completed and it is time to import the data into Pix4D w must use the Project selection tool. this will import all the data into the program to utilize for later. 

After we select the image properties and where the output file will be located it is time to run the Pix4D program. The Pix4D program to find areas where overlaying occurs and will draw points data and create a area that can be used for three dimensional analysis. 

When the initial process is completed we can then complete a point cloud mesh and create a DSM orthomosaic with indexing. this process takes a long time to complete so it is best to set the program to run and then grab dinner or complete other required work. After the completion of the Point cloud and Mesh with the DSM and Orthomosaic index we then have a completed area that can be used for a variety of other useful applications such as three dimensional maps.

 What is left after the indexing is a summary of what has been completed this holds a varity of information such as the total amount of points collected. The completed GSD and the total area that is covered. what is also completed in the program is a wire mesh of the area selected. 

Conclusion:

The pix4d program is a intense program that can be useful to the geographer who is using the UAV for mapping purposes. by using overlaying pictures it is possible to create a three dimensional map that can be later used for a variety of applications including areas that are quite large. the amount of accuracy that can be utilized is also impressive considering that the amount of time to fly a UAV to the selected area and take the amount of pictures required only needs a small amount of time in relation to how it would be to do the same thing manually. Pix4D is an impressive tool that can be utilized to great extent in areas such as surveying, evacuation data and medical and emergency services.