Pitney Bowes MapXtreme - Manual (Page 315)

Chapter 17: Working with Rasters and Grids
Raster Handlers
MapXtreme v7.1 322 Developer Guide
Table MyTable = Session.Current.Catalog.OpenTable("MyRaster.tab");
FeatureLayer MyLayer = new FeatureLayer(MyTable);
MyMap.Layers.Add(MyLayer);
VB example:
Dim MyTable As Table = _ Session.Current.Catalog.OpenTable("MyRaster.tab")
Dim MyLayer As FeatureLayer = New FeatureLayer(MyTable)
MyMap.Layers.Add(MyLayer)
Raster Handlers
MapXtreme can use one of many different libraries to load a raster image. When a raster image is
loaded by MapXtreme, it searches through these DLLs and checks if the given file can be read by
that DLL. Once a DLL/Raster format match is made, MapXtreme knows which DLL does the format
handling for the file. The format handlers are DLL’s named “xxxxxxxx.RHx”. The base part of the
name is based on the format. The extension always begins with RH, but can end in any letter (A-Z).
When searching for a format handler, MapXtreme searches the format alphabetically, starting with
RHA and continuing until RHZ. This process allows MapXtreme to prioritize which handlers are
used. For example, SPOT files are checked for before any other formats since they are just raw data
that can be confused with other formats. The SPOT handler's extension is RHD. The Halo format
handlers are named RHV. The LEADTOOLS format handlers are named RHX.
Raster handlers are located by default in the \Program Files\ Common\ MapInfo\ MapXtreme\ 7.x.x\
RasterGridHandlers folder.
LEADTOOLS Win32 Pro provided by LEAD Technologies, Inc. and HALO Imaging libraries provided
by Media Cybernetics are included with MapXtreme. The LEADTOOLS raster handler loads the
entire raster image into memory at the time the image is referenced in MapXtreme. This means that
the image takes longer to load and may fail if the image is very large due to extreme memory
requirements, but panning and zooming are faster.
The HALO raster handler only loads into memory what it needs to display, so it loads the image
faster, but panning and zooming is slower. Because of the HALO.RHV comes before
LEADTOOL.RHX alphabetically, the HALO handler will attempt to read in the image first. To change
this order, see
Configuring Custom Raster Handlers .
The following table shows the provided raster handlers and the formats they support..
Raster Handler Raster Format
SPOT.RHD Spot (.bil)
ECW4.RHD ECW (.ecw, .ers)
MRSID.RHE MrSID (.sid)
ADRGASRP.RHL ADRG, ASRP, USRP
CADRGCIB.RHL CADRG, CIB, NITF