wiki:MGOS40GdalProvider

GDAL Raster Provider for MapGuide 4.0

This page provides installation and configuration tips for the !GDAL Raster FDO Provider included with MapGuide Open Source 4.0. This document is a work in progress. Please post any feedback on this document to the mapguide-users list.

Introduction

IMPORTANT: These notes apply for MapGuide 4.0 Preview 3 and newer releases going forward. For Preview 2 and older releases, refer to the previous version of these notes

The default GDAL FDO provider provided by MapGuide 4.0 is built against GDAL 2.4.4 using its standard driver profile. That is to say of the drivers listed here:

The default GDAL FDO provider will only support the drivers where Compiled by default is unconditionally Yes

To support additional raster/vector formats, you need to source an alternate binary build of GDAL/OGR. Usually the place to get such alternate GDAL/OGR binaries is at GISInternals on the stable channel. Be sure to retain a copy of this download for future installs of 4.0 as GISInternals may rollover to a new GDAL version at any time

For the version of FDO that ships with MapGuide Open Source 4.0, the GDAL, OGR and WMS FDO providers have been refactored to use the GDAL/OGR C API for better ABI stability. What this means now (unlike previous versions of MapGuide), is that you should now be able to use replace our internal gdal204.dll with any external windows build of GDAL 2.4.4 regardless of the MSVC compiler version.

But for the purpose of recommended practice, we still suggest you use MSVC 2015 build of GDAL 2.4.4. As of the writing of this page, the file in question is:

  • release-1900-x64-gdal-2-4-4-mapserver-7-4-3.zip

Additional Driver Support

Refer to the information page of the distribution you downloaded for supported drivers.

For more information about these formats, consult the respective GDAL and OGR driver format pages.

Licensing

NOTICE: ECW Technology must be licensed from ERDAS if it used in a server application like MapGuide. Please see the following link for information on the licensing. http://iws.erdas.com/gis/can-i-use-ecw-technology-in-my-third-party-server.aspx

NOTICE: Additional plugins and libraries included in this distribution may be under radically different licenses, you MUST obtain valid licenses for each of these dependent libraries. License information for such plugins and libraries can be found in RTF format on the GISInternals buildsystem repository on GitHub?: https://github.com/gisinternals/buildsystem

A note about environment variables

GDAL has various configuration options which are driven through environment variables. For the GDAL FDO provider to properly incorporate these environment variables, you have to do one of the following:

  • Set the environment variables in question through the Computer properties dialog. This will probably also require a reboot so that MapGuide can pick these environment variables up when running in service mode. These variables will stick until they are unset from the Computer properties dialog.
  • Set these environment variables from a command line and then run MapGuide afterwards from the same session in interactive mode (mgserver run). To simplify this, you could wrap the setting of the environment variables and the running of MapGuide in interactive mode as a batch file and run that. These variables will stick for the duration of the command-line session that you run MapGuide in.

Wherever this guide refers to setting an environment variable, it is through one of these two methods.

Installation

Extract the contents of the bin directory within this zip distribution to the FDO directory of your MapGuide installation, which by default is:

C:\Program Files\OSGeo\MapGuide\Server\FDO

If prompted, overwrite any existing files. The files that you'll generally be prompted to overwrite include:

  • gdal204.dll (obviously)
  • libeay32.dll
  • ssleay32.dll
  • libpq.dll

Then set the following environment variables:

  • GDAL_DRIVER_PATH that points to the new gdalplugins under your FDO directory (NOTE: In previous versions of this guide, it told you to have the gdalplugins directory under the MapGuide Server's bin directory. The change of instructions here is to allow both FDO and the included set of GDAL/OGR console applications to be able to load these GDAL/OGR plugins)
  • GDAL_DATA that points to the extracted gdal-data directory. Certain GDAL/OGR drivers will be reading data from files in this directory and you need this environment variable set to tell GDAL/OGR where to look.

Make sure that mapguide is reading the correct co-ordinate system is being read from the source files, override it if necessary. You can use the gdalinfo and ogrinfo tools (provided with the gisinternals zip distribution) to get the true extents and coordinate systems of your datasets should MapGuide and FDO fail to properly infer this information, though in such cases indicates a defect in the GDAL or OGR provider should it fail to return this information where gdalinfo or ogrinfo does.

Debugging

The CPL_DEBUG environment variable controls whether GDAL and its plugins will output extra debug information when the MapGuide server process is running.

GDAL debug output is written to the standard output stream (stdout), so its best to use CPL_DEBUG in conjunction with running MapGuide server in interactive mode, as there is no visible stdout when MapGuide runs as a service.

The moment the GDAL provider starts making GDAL API calls, you should see output like this start showing up in the console output1.

GDAL: Auto register C:\Program Files\OSGeo\MapGuide\Server\bin\gdalplugins\gdal_ECW.dll using GDALRegister_ECW.
GDAL: Auto register C:\Program Files\OSGeo\MapGuide\Server\bin\gdalplugins\gdal_ECW_JP2ECW.dll using GDALRegister_ECW_JP2ECW.
GDAL: Auto register C:\Program Files\OSGeo\MapGuide\Server\bin\gdalplugins\gdal_MrSID.dll using GDALRegister_MrSID.
GDAL: Auto register C:\Program Files\OSGeo\MapGuide\Server\bin\gdalplugins\gdal_ECW.dll using GDALRegister_ECW.
GDAL: Auto register C:\Program Files\OSGeo\MapGuide\Server\bin\gdalplugins\gdal_ECW_JP2ECW.dll using GDALRegister_ECW_JP2ECW.
GDAL: Auto register C:\Program Files\OSGeo\MapGuide\Server\bin\gdalplugins\gdal_MrSID.dll using GDALRegister_MrSID.
MrSID: Opened zoom level 1 with size 2500x2500.
MrSID: Opened zoom level 2 with size 1250x1250.
MrSID: Opened zoom level 3 with size 625x625.
MrSID: Opened zoom level 4 with size 313x313.
MrSID: Opened zoom level 5 with size 157x157.
MrSID: Opened zoom level 6 with size 79x79.
MrSID: Opened zoom level 7 with size 40x40.
MrSID: Opened zoom level 0 with size 5000x5000.
MrSID: Opened image: width 5000, height 5000, bands 3
GDAL: GDALOpen(D:\projects\Client\Data\SDF/DO_S03_9608_40.sid, this=0FB15438)  succeeds as MrSID.
GDAL: GDALClose(, this=0FB15D18)
GDAL: GDALClose(, this=0FB16088)
GDAL: GDALClose(, this=0FB16410)
GDAL: GDALClose(, this=0FB16798)
GDAL: GDALClose(, this=0FB16B20)
GDAL: GDALClose(, this=0FB16EA8)
GDAL: GDALClose(, this=0FB17230)
GDAL: GDALClose(D:\projects\Client\Data\SDF/DO_S03_9608_40.sid, this=0FB15438

1 This is just example output (copied from the GDAL provider guide for 2.2) showing the kind of output you would see.

Remember to unset CPL_DEBUG when finished as performance is significantly slower when GDAL debugging is turned on.

Configuration

The default serverconfig.ini settings set by the installer should be sufficient. No additional serverconfig.ini modifications are required.

In addition to CPL_DEBUG, GDAL offers many other runtime configuration options via environment variables. See here for the full list

Previous notes

Last modified 4 months ago Last modified on Jun 26, 2021, 2:06:33 AM