GIS Frequently Asked Questions

Here are common GIS questions about our General Plan and Emergency Preparedness maps. If you cannot find your question here, contact us.

What is GIS?
What is a Shapefile?
Is GIS expensive?
Does it take a long time to implement GIS?
Do I need a GIS person on staff?

1. What is GIS?

GIS, or Geographic Information Systems, is the hardware, software and human elements that construct digital maps where every point, line and shape is connected to an information database. GISCENTRAL takes hard-copy data, paper maps, slides, records and spreadsheets, and turns them into spatial data for user applications. The user chooses which database information is displayed as a layer on a digital map accessible by a PC from virtually anywhere in the world. The options are virtually limitless.

2. What is a Shapefile?

Simply, a shapefile is the starting point for GIS.  It contains the basic information dataset that defines the geographic area being mapped, the attributes of the area, and generally what makes the GIS area unique. 

In technical terms, as described at www.esri.com, a shapefile stores nontopological geometry and attribute information for the spatial features in a data set. The geometry for a feature is stored as a shape comprising a set of vector coordinates.  Because shapefiles do not have the processing overhead of a topological data structure, they have advantages over other data sources such as faster drawing speed and edit ability.

Shapefiles handle single features that overlap or that are noncontiguous. They also typically require less disk space and are easier to read and write. Shapefiles can support point, line, and area features. Area features are represented as closed loop, double-digitized polygons. Attributes are held in a dBASE® format file.  Each attribute record has a one-to-one relationship with the associated shape record. 

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3. Is GIS expensive?

Yes and no.  It can be prohibitively expensive if a city wants to create a GIS department, purchase necessary software, servers, and personnel. The cost of this approach, excluding personnel, can easily run to a quarter of a million dollars or more. 

Implementing GIS via outside services is generally more cost effective, depending on exactly what the Client wishes to achieve.

PVNET is a 501c3 non-profit organization that provides extremely low-cost GIS solutions to a wide variety of clients.

4. Does it take a long time to implement GIS?

When using PVNET services the time to implementation is driven by the Client. When the Client provides required information and reviews PVNET product in a in a timely manner final delivery is usually a few weeks from contract signing.

5. Do I need a GIS person on staff?

It is often wise to have a full or part time GIS staff person. PVNET can train an existing staff person to fill that position or provide direction for hiring a GIS skilled individual.

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