At Lewis & Clark College, most of your GIS work is done in the Dubach Labs; this creates challenges since files are not saved after your session. This means that your data will need to be stored externally to be used again. Below are some important considerations.
Saving map project data using relative paths
Whether you are using ArcGIS or QGIS, your GIS projects typically consist of (a) multiple spatial data input files and (b) the map project file in which you compile, analyze, and display these data layers. Your map file can reference these data files in two basic ways: absolute references and relative references, or paths. You’ll want to use relative references so that you can work with your spatial data on any computer. Here’s how to do so:
- In ArcGIS, go to File > Map Document Properties, and click the relative pathnames box at bottom.
- In QGIS, go to Project > Project Properties, and verify that Save Paths toward the top is set to relative.
Make sure to keep all of your data files and your map project file together in the same location (e.g., all inside a special folder on your desktop); this way you can readily preserve relative paths when you do the below.
Zipping and unzipping data
If you are using Google Drive or emailing your data, it’s best if you assemble it all into one big zipped file. This will be easy if you already have your data files and map project file in a special folder as recommended above. When you download the zipped file, you can then unzip.
- If you’re on a PC (using ArcGIS or QGIS): select the enclosing folder or all your files, then right-click, point to Send to, and click Compressed (zipped) folder. To unzip, right-click, then click Extract All.
- If you’re on a Mac (using QGIS): select the enclosing folder or all your files, then right-click and choose Compress. To unzip, simple double-click the zipped file.
Uploading and sharing in Google Drive
You can always save your data with a flash (USB) drive. If you want to use Google Drive, and are working with large (generally raster) spatial data files, first make sure you have enough room on Google Drive: you have 30 Gbytes of storage to share across all your Lewis & Clark Google Apps, and up to 15 Gbytes on any personal Gmail account. Just look at the bottom left of Google Drive to see how much space you’ve used.
Here’s how you can upload and download data:
- Open Google Drive, and the appropriate destination folder. Then simply click New > Upload Files… or drag your zipped file onto the folder directory. Make sure that the file is completely uploaded before exiting the window!
- To download, right click on the zipped file, then select Download. Then proceed with the unzipping procedure above.
Here’s how you can share an uploaded file or enclosing folder so others can access them:
- Open the file or folder, then click Share in the top-right corner. Under People, enter the emails of people or Google Groups. You can also search for contacts by typing them into the box.
- Choose the type of access you want to give these users by clicking the dropdown arrow to the right of the text box. Then click Done. The users will receive an email letting them know you’ve shared the file or folder with them.