Week 10: Vector Analysis 2

This week we completed the second portion of the Vector Analysis series for lab. We learned how to use the buffer and overlay tools. We were finally introduced to Python and creating basic script writing by running a buffer. Below are the steps I took:

1.       TOC > Water_Buffer > Open Attribute Table > Add Field > short integer type > “insd_wbuf”

2.       Keeping the attribute table open, right click on “insd_wbuf” > Field Calculator > 1 > for every feature in the layer

3.       The same process was repeated for the “roadsbuff300m” except the field was named “insd_rbuf”

4.       TOC > roadsbuff300m > Open Attribute Table > Add Field > short integer type > “buffdist”

5.       Keeping the attribute table open, right click on “roadsbuff300m” > Field Calculator > 300 > for every feature in the layer

6.       Next, I ran a Union Overlay by: Arc Toolbox > Analysis Tool > Overlay > Union…then for input features, I selected Water_Buffer and roadsbluff300m. I named the output feature class as S:/Intro2GIS/10_Vector2/V2Data.gdb/Union_Buffer.shp. I joined attributes as ALL and left the Gaps allowed option checked and selected ok.

7.       Select by Attributes > insd_rbuf = 1 AND insd_wbuf  = 1. Then I exported the selected features from TOC > Union_Buffer > Data > Export Data to a new feature class called buffer_union_export

8.       When this new layer was added to the map, I only selected this layer, the Roads layer, and the Water layer to appear on the map.

In this lab, we used the union tool to create the buffer needed to isolate the parameters for our campsites. Below is a map of potential campground sites with the buffers and overlays created.

Potential Campground Sites

Weeks 7 & 8 Lab: Data Search

This week's lab was part scavenger hunt, part learning a new stitch-lot's of start over and repeats!      First, I went on the search for data. I went to the Saint Johns County, Florida website. They provided most of my data. They have a Data Depot Section with tons of free, downloadable data available. I downloaded their creek data file for my hydrography. I went this route instead of downloading major rivers, as I didn’t really see any in the county. I also downloaded their city data verse FGDL.org. Well, I downloaded FGDL.org too, but after adding that data set to my first map, and trying to build a query to only include cities in St John’s county, I decided there was too much useless data that made the map messy. I also chose the county layer from the Data Depot, to save time from having to clip the county boundary from the entire state of Florida. They also provided an already clipped DEM Raster layer which totally saved my life…or a lot of time, anyways. I did use the major highways data file from FGDL.org. I was not fond of the roads file that the Data Depot provided-it was all streets, all 14,000 of them. I only wanted major highway systems to keep my map cleaner. I downloaded the NW quadrant of St Augustine for my second map from the Labins website. I chose the Transverse_Mercator projections for Maps 1 and 2. It saved a lot of time just clipping the data layers to the county boundary. Of course, I spent a lot of time on my first map figuring that out. But hey, isn’t that part of the GIS learning process??!! The one area I ran into huge trouble and just could not figure out was the Land Cover Raster-I followed the Raster Project data tool steps to a T, and it clipped it-just not to any county boundary I added…it was noticeably larger. Thus, I decided to just go with the Basin Catchment layer that good ole’ St Johns County GIS Data Depot provided. This counts as land cover, right? One could argue? I feel like I am on the precipice of getting this whole Projections game down but I am not quite there yet. Practice makes almost perfect, though! Here are the maps I projected!

Map 1: Conservation Parks, Creeks, & Wetlands

 Map 2: Aerial View of Saint Augustine, Florida

 Map 3: Topography & Basin Catchments of St Johns County