This will be my final update on my GIS Internship for the semester. I finished out the last couple of weeks with a few ESRI courses (3D Visualization, 3D City Information, Network Analysis, and Terrain Analysis) and my WQLM impervious surface project. When I finally figured out the problem with the impervious surface data, I was grateful to be able to finally start the project. The workflow involved adding a county mosaic, a basin outline layer, and a digitized rooftop layer to a blank map. With an editing session open, I worked my way through my assigned basin creating polygons over rooftops for the digitized rooftop layer. I got mostly through the entire basin, but I probably have at least two more hours of digitizing before the project is complete. Attached are pictures of the layers I used to create the polygons to give insight on what my process looked like.
For GIS Day this semester, I created my own event to celebrate. The event took place in my office at home and my audience was my 7-year-old stepson on Skype. The format of the event was an informal discussion about GIS using things relevant in his life to help explain GIS. The most effective way to explain geographic information systems to him seemed to be using his favorite game, Dragon City, as a reference. In the game, you have several pet dragons that live in different little dragon worlds. When you click your dragons or your "worlds" on the main map, information about them appears, like their names and health statistics. This was very useful since it was very similar to GIS systems attaching information to geographic features.
This week I created my GIS portfolio website. I find it more useful to have an online platform to display GIS work since GIS files can often be large, have a long process summary, and involve maps or photos. Bringing GIS projects into an interview setting by hand would probably result in a lot of paper being used and may even come off as unorganized if multiple pages were used for one project. I used the Wix website builder to build my portfolio and did not find the program difficult to use. There were many options available to add to my website that were free and that were exactly what I needed (for example, the contact form). I even was able to add an insert of THIS blog into the portfolio site so that interviewers could look at my GIS updates in real time.
This week's lab introduced us to ArcGIS Pro. This was actually my second time using ArcGIS Pro and I actually enjoyed it. The first time I used the program was about 3 years ago and I was not as comfortable as I am now with ArcGIS in general. This is probably the reason I found it difficult to navigate and confusing with panes opening and docked at the right side of the screen. This time using ArcGIS Pro, however, went very smoothly and I found the program incredibly simple to navigate considering my experience with ArcGIS now.
The goal of the lab was to introduce us to Landsat imagery using ArcGIS Pro, dealing with its temporal scales and multispectral benefits. We looked at several time series of nuclear accidents in Ukraine, burn scars in Ukraine, and burn scars in Australia. Using ArcGIS Pro's time slider facilitated easy visualization of changes over time. Also, changing band combinations made viewing ground changes through clouds (using SWIR bands) much easier. The final exercise was the most immersive, using a vegetation index and a time series of images to see how vegetation regenerates after fires.
Below are a few images from the lab process.
Spectral reflectance curve of water in a reservoir:
Spectral reflectance curve of forested area:
Vegetation index of post-fire land:
Dark areas represent areas that were not burned. No burn scars (red) exist, thus indicating that vegetation has regenerated since the fire. The red areas are areas of water and not burn scars.
This lab involved the use of a student-produced LULC map (refer to 02/01/2017 post) to calculate the overall accuracy of the LULC map using an unbiased sampling system and google maps street view.
For this assignment, I used my previously completed LULC map. I added a new polygon to the working .mxd file that covered the entire surface of the map. I used the Create Random Points tool (in the parameters of the created polygon) to create 30 random points that covered the entire surface of the map. When they point layer was created, I added two fields to its attribute table that were for a Yes/No truthing and for inputting a new code where it was needed (True_YN and New_Code).
I opened Google Maps and navigated to Pascagoula, MS where my map was centered. One-by-one I selected the random points, found them on google maps, enabled street view (to view the exact point more clearly), and discovered whether or not my classification (where the point fell) was consistent with the real-world street view. If the classification was correct, I put a Y in the True_YN field of the points layer (with an editing session in progress). If the classification was incorrect, I put a N in the Ture_YN field and a new code that better suited the point in the New_Code field of the points layer. I followed this process until all 30 random points had a Y or N and a new code if needed. I then divided the number of Ys (21) by 30 to get a percent accuracy score (70.0%).
This week I began working on the impervious mapping project for Escambia County WQLM. Again, my role in the project is to digitize impervious rooftops in one remaining basin in Escambia County. Much of my time in the beginning of the week was devoted to familiarizing myself with the data and process of digitizing rooftops. I found that the basin layer, previous digitized rooftop layer, and county mosaic layer were required to be on the ArcMap display to work through the process.
I changed the symbology of the basin layer to a hollow outline so that I could see the basin and also the mosaic at the same time. I changed the scale to 1:400 for accurate digitizing. I started an editing session and used the Create Features function in editor to create rooftop polygons to draw polygons over all rooftops in the basin. I worked back and forth from the bottom of the image (starting at previously digitized rooftops) to keep track of which rooftops were digitized.
The first day of the project, I spent a lot of time digitizing a chunk of approximately 70 rooftops. When trying to save the edits to the rooftop layer, ArcMap stopped responding and crashed without saving the edits. The next day I worked on this, I only digitized approximately 10 rooftops before trying to save (so that I didn't waste as much time) and the same freezing and crashing process occurred.
I did not get screenshots from these events yet since I was not anticipating the crash. I will continue work on this project next week on different computers to see if this might fix the problem (and get screenshots early of my process).
As sometimes other school assignments can take priority, this week I also committed most of my lab time to GIS class assignments rather than internship hours. I completed ESRI courses at home after the lab hours were closed. The following are the classes I completed and skills that I learned. The model building course was easiest for me because of my experience building and using models. The 3D data exercises, however, I was very unfamiliar with as I have only had one previous exercise in displaying 3D data. Most of the terminology and workflow was new to me. 1. Building Models for GIS Analysis Using ArcGIS
- Learned about different parts of models
- Determined an existing model's inputs, intermediates, and outputs
- Created models
- Used model-builder to learn about parameters
- Learned the process leading up to sharing a model 2. Creating 3D Data Using ArcGIS
- Learned about different types of 3D data and how they can be used
- Created 3D surfaces from existing 2D features
- Followed workflows that explained different techniques in creating 3D data 3. 3D Analysis of Surfaces and Features Using ArcGIS 10
- Learned how to determine visibility between observed and target features
- Determined steepest paths in 3D data
- Created and ready profile graphs
- Followed workflows to calculate area and volume statistics from 3D features and surfaces