GIS5103 Module 3: Debug & Error Handling

-

Switching from the heat to the onslaught of rain recently has made me sick again—you could say I've caught a... bug!

Speaking of catching a bug, aside from the common cold I've been experiencing, we learned about common Python and geoprocessing errors, as well as general debugging and error handling in Python scripts this week. Troubleshooting can be headache-inducing, but at the same time, oh so rewarding when you can overcome them. Python thankfully makes this process as painless as possible. Again, I'm reminded of how kind Python and its editors can be in identifying what causes a script to fail to run or to break in the midst of a run.

This week, we were tasked with three different pre-made scripts this time. For two of the scripts, we were able to fix some errors and ensure they ran. The final and third script, however, required us to use try-except statements to bypass erroneous sections of Part A while still allowing Part B to run.

Script 1 - Feature Class Field Names. Prints out all the names of each field found in the "parks.shp" file.

The first script covered correcting a few minor errors with the script. IDLE was my preferred editor, and getting more comfortable with the different error messages was nice. I'm noticing less anxiety whenever I see red text. Reframing it as approaching red, erroneous-like text with an open mind of "check this interesting thing out" has been helpful. Honestly, it's helped me overcome some perfectionism and encouraged more trial and error in my work.

Script 2 - Project Spatial Ref & Layers. Prints out the ArcGIS Pro project's spatial reference and its layers.

As shown above, the second script was another fixing errors. It prints out the project's spatial reference, NAD 83 State Plane Texas Central FIPS 4203 Feet. It also pulled the layer names from the map, which included parks, bike_routes, facilities, and county. This one helped me notice errors when it comes to functions in particular, reminding me about case sensitivity.

Script 3 - Parks Try-Except Statement. Implemented a try-except statement to bypass any errors in Part A of the script and lets Part B run successfully after.

Script 3 Flowchart.

The last script was fun to wrap my head around. Putting in a try-except statement made me think of using a net to cast to catch an error. So, I tried thinking of the try-except statement as a trap block to case potential erroneous parts of the script in Part A. I chose to not include the initial print statement to ensure that Part A was attempting to run. I also wanted to make my exception statement have an additional error text when printed, so  I did add an f-string to that clause. I like using f-strings and like how they look when I read back a script, personally.

For fun and to challenge myself, I also wanted to fix the script to see if I could get it running. Definitely having Script 2 and also seeing Part B completed with no errors gives you quite the foundation and leg-up on fixing Part A. With a bit of adjustment and switching the placement of the Part A success print statement (due to it not printing when I wanted it to), I was able to get it running as you can see below.

Script 3 - Parks Working. Prints out the parks layer name if present in project's map, then prints success statement. If not, it would have printed the previous error message.

Now, future troubleshooting doesn't seem so daunting to face after more exposure (therapy). Bring on the scripting scaries!

Comments

Post a Comment

Popular posts from this blog

GIS5050 Final Project: The Bobwhite-Manatee Transmission Line

-
Image
The time has come for the final project to be completed and the class done! It's a bit wild for me to think that much time has passed where my first GIS grad course is over. Throughout the entire final project, I had a lot of fun actually creating these maps -- maybe too much since I ended up losing sleep some days because I was so in a flow state, so into just constantly trying and tweaking ideas of how the basemap should be or how the insets should look, etc. I think the biggest takeaway I have from my first grad course in a long time is that I'm way too much of a perfectionist. I even chuckled at myself how frequently I wanted to redo the recordings of my final presentation just because I didn't like how I said something, stuttered, or so on. At this point, no amount of minor editing will change my grade that drastically -- it's not worth it to mull over to no end. Ultimately, I'm still very proud of the map deliverables I created and are maps I would be content ...
Read more

GIS5007 Module 3: Cartographic Design

-
Image
I'm back from vacation and was itching to start on my layout for this module, because this week's lab is on Cartographic Design. With Cartographic Design, we were heavily advised to keep Gestalt Design Principles in mind, including visual hierarchy, contrast, figure-ground, and visual balance. If one doesn't keep these principles at the core of map-making, then there's a high chance the message you're trying to send will be lost or misinterpreted. Ward 7's Public Schools. We focused on the elementary, middle, and high schools in Washington, D.C.'s Ward 7, with other environmental features, like parks, waterways, and roads, accentuating it. As you can see from the map above, we had to create a map of the public schools located in Ward 7. Due to the awkward shape of Ward 7's polygon/boundary, it was a testament to my confidence when placing my map elements. I moved my elements around so much, slightly tweaking them here and there, that I resorted to scribb...
Read more

GIS5007 Module 2: Typography

-
Image
I'm coming to the realization that I'm becoming more of a GIS/map nerd than I thought I'd ever be. I think a large part of it comes down to my perfectionism, to a fault; however, I also want to believe it's because I long for a creative outlet, especially when I'm stuck making a certain type of map at work. They're not bad maps by any means, but there's a certain formula and structure to them that doesn't allow for much experimentation, which speaking of experimentation... It was so nice to finally get my grubby GIS hands on more creative map-making again! This week's module focused on typography, which made us consider the importance of labels and how we stylize, set, and size them can affect the legibility of features. The lab walked us through the process of building a solid foundation for a map layout that focuses on the major features throughout Florida. These features were rivers, swamps/marshes, cities, and counties. One of my first assignment...
Read more