Esri Projection Engine Database Documentation

The Esri Projection Engine (PE) libraries deal with coordinate reference systems and their projections and transformations, as well as providing many support functions such as calculating distances and areas, converting between lat/lon notations, importing/exporting objects from/to well-known text (WKT) strings, converting from/to well-known ID (WKID) values, etc.

To perform WKID conversion, the PE contains a comprehensive database of known coordinate systems, datums, ellipsoids, units, etc. This database is regularly updated and kept in sync with the EPSG database.

This documentation is based on ArcGIS Pro version 3.3. Entries taken from EPSG are from the 11.003 version of the EPSG database.

Documentation files are found in the following directories:

Directory	Contents	Filenames
json	All factory objects in JSON format	pelist\<objtype>.json
csv	All factory objects in CSV format	pelist\<objtype>.csv
text	All factory objects in TXT format	pelist\<objtype>.txt
objedit	The entire PE factory in objedit format	\<objtype>_\<rectype>.txt
fgdb	All factory objects with an area extent in feature class dataset	pe_area_extents.gdb\ pelist\<objtype>
shp	All factory objects with an area extent in shapefile dataset	pelist\<objtype>.shp, etc.
proj4	Updated PROJ4 files	esri
gdal	Updated GDAL files	esri_extra.wkt esri_epsg.wkt
other	Other files	PE_user_defined_objects.pdf proj4-esri.txt

Notes

Each object has a well-known ID (WKID), also called a code or factory code. WKIDs are unique within an object type, like a unit of measure, or a set of objects, like the coordinate reference systems.
Some entries have undergone a "code change". A code change can occur because an entry was added to the Esri software first and was given an Esri WKID. Most Esri WKIDs are in the 1xxxxx range. If EPSG adds the entry, we will change the WKID to the EPSG code (range is 1024 - 32767). Another reason for a code change is because of an error in the original definition. In the tables, the WKID field contains the original code while latest-WKID field is the new code.
If an entry comes from the EPSG database, then the authority name is "EPSG" and the version value is in the form "EPSG-version(Esri-version)".

The "EPSG-version" is either the EPSG version in which the entry was added or the EPSG version in which the entry was last updated (with no way to tell which one it is).

The "Esri-version" is always the Esri version in which the entry was added.
The GDAL file "esri_extra.wkt" should replace the following files in the GDAL distribution (http://www.gdal.org):
- data/esri_extra.wkt
- data/esri_StatePlane_extra.wkt
- data/esri_Wisconsin_extra.wkt
The PROJ4 file "esri" should replace the following files in the PROJ4 distribution (http://proj4.org):
- nad/esri
- nad/esri_extra
Area extents are specified in degrees (from Greenwich).
Accuracy values in transformation entries are specified in meters.
Documentation of the objedit files can be found in the file "other/PE_user_defined_objects.pdf".

Issues

Find a bug or want to request additional documentation? Please let us know by submitting an issue.

Licensing

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

A copy of the license is available in the repository's license.txt file.

Esri / projection-engine-db-doc

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Esri Projection Engine Database Documentation

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Notes

Issues

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