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Data Standards for TCEQ GIS Data

This page provides information on Spatial Data requirement standards. It indicates the minimum required accuracy and has links to system requirement information.

Horizontal Accuracy for Positional Data

The TCEQ Spatial Data Documentation Process specifies a target accuracy of 25 meters for agency spatial data.

TCEQ procedures specify that:

"All horizontal positions will be measured and recorded in latitude and longitude coordinates. The format shall be in either decimal degrees carried out to at least 4 decimal places or in degrees, minutes, and seconds with the seconds carried out to at least 1 decimal place. All longitudes in the Western Hemisphere shall be prefixed with a negative sign."

Important: Decimals must be carried out to enough places to correctly reflect the reported accuracy. In order to meet the TCEQ minimum accuracy standard of 25 meters, latitude and longitude coordinates should be carried out to at least 4 places for decimal degrees and at least 1 place for decimal seconds. Use of GPS equipment or DOQQ interpolation may yield additional decimal places beyond these minimum accuracy requirements; in such cases, as many as 6 decimals may be required to reflect the accuracy of that position. (A coordinate stored with 6 decimal places reflects an accuracy of approximately 11 centimeters).

The tables below are provided as a reference for the levels of accuracy that may be obtained when carrying positional coordinates, in either decimal degrees or degrees-minutes-seconds, to different decimal places.

Decimal Degrees


TCEQ Spatial Data Dictionary (Point)

Required fields for Point Spatial Data sets.

The attributes listed below represent the minimum set of fields which must be included within all Common Agency Datasets that track geographic point locations of interest at the TCEQ as specified in the TCEQ Spatial Data Management Strategic Plan. These include regulated facilities, monitoring stations, sampling sites, and incident locations.