<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 15 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Aptos;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
font-size:12.0pt;
font-family:"Aptos",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Aptos",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style></head><body lang=EN-US link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>I vaguely recall someone complaining about this 15 years ago, but not since then.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Paul can better speak for the reason, but I think it was because we needed to fit it into the header of the geometry and still have enough bits left for the geometry type etc and 2 bits extra for growth.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>So I would say it’s very unlikely we’d lift this restriction.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div style='border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif'> G. Allegri <giohappy@gmail.com> <br><b>Sent:</b> Monday, October 27, 2025 5:46 AM<br><b>To:</b> postgis-users@lists.osgeo.org<br><b>Subject:</b> Why PostGIS sets a max value for SRID IDs?<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Hello list,<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I'm working on two projects where custom CRSs, with custom authorities and IDs are provided.<o:p></o:p></p></div><div><p class=MsoNormal>Both projects use IDs with numbers beyond SRID_USR_MAX=998999 [1], which is hardcoded in PostGIS for the spatial_ref_sys id field values.<o:p></o:p></p></div><div><p class=MsoNormal>I can use the auth_id, of course, but having to reassign an id < 998999 is a bit problematic for two reasons:<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>- I have custom transformation pipelines defined inside the proj.db, where the custom IDs are defined for CRSs. <o:p></o:p></p></div><div><p class=MsoNormal>- other softwares (QGIS, Geoserver) can use the custom IDs but they cannot match the geometries SRIDs returned PostGIS<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I wonder if there's a technical reason for the SRID_USR_MAX constant, and if there's any change to remove it in the future.<o:p></o:p></p></div><div><p class=MsoNormal>And I wonder if others have faced the problems I'm having due to this, and what are the solutions they came up with.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Thanks,<o:p></o:p></p></div><div><p class=MsoNormal>Giovanni<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>[1] <a href="https://github.com/postgis/postgis/blob/5dc95f1bc3047b048128616d4543b603b8bbdca7/configure.ac#L1554">https://github.com/postgis/postgis/blob/5dc95f1bc3047b048128616d4543b603b8bbdca7/configure.ac#L1554</a><o:p></o:p></p></div></div></div></div></body></html>