My comments are based on my experience working as a GIS Specialist, GIS Technician, and GIS intern over roughly 5-7 years and in three different states.
-What are the GIS positions that allow field work?
As Steven Jay mentioned, many GIS positions are heavily office-based positions because a lot of time is spent 1) cleaning up, analyzing, and presenting field-collected data in the office. However, my perspective is that the percentage of fieldwork is based on 1) what type of data your organization collects/maintains and 2) what kind of people you support with GIS operations.
Example #1 I worked as a contractor for an Oil & Gas company in Kansas City, Missouri and had zero field experience, because all of the required data was in paper, Excel, or PDF format.
Example #2 In Illinois, I worked for a county-level government agency that maintained parks, trails, and conservation resource area. At least 15% of my time was spent either 1) collecting or verifying field data related to trail geometry and attributes (e.g. grade, slope, width, etc.), park and amenity infrastructure (signs, shelters, etc.) for use in planning and maintenance programs, and 2) training natural resource management staff on using GPS units to collect field data related to resource management, invasive species control, etc.
-How useful is a GIS portfolio?
I have been through both sides of the hiring process. As a member of the hiring team, I find a small portfolio can be helpful to review because it helps provide context to your resume and the interview conversation - telling more of your story, and can sometimes provide the deciding factor between two candidates who are equally qualified on paper.
As a job seeker, I once applied for a job where I never met the hiring team and all they had to review my qualications was my portfolio and resume. In that case, the portfolio gained more importance in the hiring process.
Either way, I have found both as a job seeker and hiring team member that the resume and cover letter still carry a lot more weight in the hiring process unless the job announcement or hiring manager explictly requests a portfolio.
-What are the best ways to display data?
I believe that map-based ways of visualizing data are still the most popular and powerful method for displaying data. In that statement, I include both static map methods (paper, PDF, images, etc.) and interactive methods (web GIS, GeoPDF, etc.) Each has their pros and cons depending on the project and audience. Tables and charts are also quite valid and popular for brochures, posters, and handouts. As Jay put it, each project is different and it depends on what the requester needs or wants, and what is feasible with your available resources.
-What are other programs used in the GIS industry that are good to know?
Surprisingly, I would say that you really need to know Excel or any equivalent spreadsheet software. GIS Source data often needs a little (or lot of) cleanup before it is ready to use in GIS and Excel is very versatile for that. Know at least one or two programs for manipulating GPS data (e.g. DNRGarmin, ArcPad, ArcToolbox, Trimble, etc.) if you work with field data. SPSS or R are handy for doing statistics alongside ArcGIS. And always explore open-source GIS tools, from QGIS\Grass to GDAL, etc. as ArcGIS doesn't do everything well, and is so expensive for individual license.
-How important is it to have a GISP?
I think that the GISP is gaining more importance as the GIS industry tries to increase its visibility and credibility in society and I intend to pursue the GISP myself as a benchmark of my experience and knowledge. You may also see an increase in the number of job announcements where a GISP is required or preferred.
Andrew Stickney