Where else can I go to find more GIS data for…
How do I download data via FTP?
Refer to this document to access our FTP site. If you have a UNR NetID, you can access our FTP side via the Keck homepage. Under the Quick Search bar, click the “FTP Directory” link and enter your credentials.
How do I use the imagery and services provided in ArcMap?
The services we provides all function slightly differently, but generally the data will be downloaded in a zipped folder. Navigate to that folder (often the default place newly downloaded items are stored is in a directory called “downloads”) and right click on your zipped folder. Choose “extract all” and this unzips your folder, making the data usable. You might notice quite a few unexpected files. Often time associated files such as .prj, .shx, etc may accompany your data. These are supposed to be there and they all serve a purpose, often times georeferencing the data you have just downloaded. This means it has been assigned a location on a map.
Now open ArcMap. At the top of your screen choose the “add data” button which looks like a folder with a “+” over it. Navigate to where you saved your data. You will notice not all of the files show up, only the ones readable by ArcGIS. Usually this will be shapefiles, image files, and geodatabases.
Why doesn’t my data line up with pre-existing data on my map?
Most likely because the map projections between your newly imported data and your existing data do not match.
What are coordinate systems and why are they important?
Geographic and Projected coordinate systems split the earth up into transferable units that relate to points on a map. Geographic coordinate systems define an object’s absolute location on the earth. Projected coordinate systems are a little more abstract, yet very important to GIS users. Because the earth is a sphere, representing it on a 2D map is difficult and the earth will not be represented perfectly. Projected coordinate systems basically focus on one continent, region, etc. in order to reduce skew and accurately represent objects in the area of study.