Spatial -

NOAA Datums Videos 2014

Differential correction with NA2011 and the newest epoch of NAD83

See our and Datums Basics and GPS Tutorials for the long-awaited results of months of rigorous testing and peer review

Trimble Positions software has replaced Trimble GPS Analyst in ArcGIS 10.1

ALASKA GPS and GIS users - check out Joel Cusick's Datum and Projections presentation Feb 2013

ArcGIS 10.1 - New and Cool improvements see Presentation from Melita Kennedy, ESRI : Projections and Datums Dec 2012

Home GDB Basics Trimble GPS Analyst: GPS data in a Geodatabase
Trimble GPS Analyst: GPS data in a Geodatabase PDF Print E-mail

The Trimble GPS Analyst extension allows you to

    1. Store GPS data in the GDB


    Your GPS data is added to your GIS as feature classes.  The Trimble GPS Analyst Extension also allows you to store the actual GPS-collected positions that make up those features in the GDB.  The data is stored in the GPS Sessions folder.

    2. Estimating accuracy values

    GPS Analyst estimates accuracy values for the GPS positions that make up each feature.  These estimated accuracy values are based on indicators of GPS quality such as PDOP and the proximity and type of base station(s) used to correct the data.  These values are stored in the GPS Session folder and can be used to edit features vertex-by-vertex.

    GPS Analyst also estimates accuracy values for each feature itself. For line and polygon features that are made up of several vertices, the estimated accuracy is represented in two ways -


    Average estimated accuracy, the average for all the vertices in the feature,

    Worst estimated accuracy, the value of the vertex that has the largest estimated accuracy of all the vertices in the feature.

    Since a point feature consists of only one vertex, the worst estimated accuracy and the average estimated accuracy are always the same.  The average and worst estimated accuracy values are stored as attributes in the feature class table for GPS-enabled feature classes.  These values can be used for decision-making when editing features within a feature class.

    3. Validating features

    During validation, GPS Analyst compares the worst estimated accuracy of features against the required accuracy you specified for each feature class.  The degree of accuracy you set will depend on the type of feature collected and the purpose of the information. For example, underground cable features that maintenance crews will need to locate and repair require better accuracy than signpost features that are clearly identifiable.  Those features that do not meet the required accuracy will be flagged as such.


    4. Rebuilding features

    Should your accuracy requirements change, you can always change the required accuracies.  The features can be validated again and rebuilt to meet these new standards.