Wednesday, February 11, 2015
GIS4043: Projections Part I
This week in GIS4043, we learned about Georeferencing and:
-Coordinate Systems- How to Project an Image- How to Calculate Field Geometry
- And How to create a layer from a selection
We also learned that the ability to accurately locate geographic features is critical in both mapping and GIS, such as in the case of a responding emergency vehicle to your exact location-- don't be late, please.
The Lab exercise involved making three maps using different projection systems: Albers Conical Equal Area, Lambert Conformal Conic and Universal Transverse Mercator. We used the Project tool in ArcGIS to reproject a data layer. Trying to remember where all the Tools are is still a challenge for me. But, thank goodness I don't have to recall their precise location, on the Main Toolbar, under the ArcToolbox icon, down to the Data Management smaller toolbox, down once again to the toolbox tray known as Projections and Transformations and finally, all the way to the end to the hammer, I mean tool, Project. I can always review all the tools and icons as I am searching for the right tool for the job. Eventually, after many more maps and Labs, I will instinctively know where everything is located or how to find whatever I need.
I also learned that a ".prj" file is projection information associated with GIS data files. Interesting...more file extensions to recognize and catalog.
I had fun with this map but some of the challenges included setting one scale to fit all three maps and making a Legend using Excel (Insert>Object, then select Excel from the list). I elected to use a number system to identify the counties we were interested in, instead of using color for each county. I wanted to highlight the area differences even though they were minor for the most part. By only numbering one map with the counties, I hoped to focus the users attention here so they would use the center map (Albers Conical Equal Area) to compare the other two maps.