MapInfo Pro Developers User Group

I am trying to add 61 raster images in the map window and it is very fast in mapinfo 12.5 (18 seconds) but very slow in 2019 (1 minute 7 seconds). Does anyone know the reason? Here my codes.

Sub Imagery_Render(ByVal tableName as String, ByVal zoomMin as Float, ByVal zoomMax as Float)
       Dim windowId as String
       Select TabFile from tableName Into tblTifFiles
       Set Event Processing Off 
       Fetch First from tblTifFiles
           windowId = UI_GetMapWindowID()
           Do While NOT EOT(tblTifFiles)
                Dim tabFile, name as String
                tabFile = tblTifFiles.TabFile
                Open Table tabFile Interactive 
                name = TableInfo(NumTables(), TAB_INFO_NAME)
                Add Map Layer name Position 5
                Set Map Window windowId  Layer 5 Zoom (zoomMin, zoomMax) Units "mi" On Display Off
               Fetch Next from tblTifFiles
          Loop
     Set Event Processing On

Close Table tblTifFiles
End Sub

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

If Pro 2019, when you load a TIFF file for the first time, it will probably create an overview cache which is stored in a PPRC file with the TIFF. This takes a little time and so the first time you load the TIFF, it will be slower. The next time you open the TIFF the PPRC file will already be present and so it will be faster as it does not need to make it again. 

If your TIFF files are in a read-only directory (for example if they are on a DVD) then the PPRC file cannot be stored. It will be kept as a temporary file that will be deleted when you close the TIFF. This will cause it to be slow each time you open the TIFF because the PPRC is created every time.

There are other settings which have an impact on this behaviour. In the backstage area under Options and MapInfo Pro Raster Preferences, there is a setting under "Display" called "Generate Raster Overview Cache" that can modify this behaviour. 

If you really want it to behave like 12.5, then in the same preferences dialog, in the "Raster Formats" page, you can disable the TIFF driver (both Native and GDAL) and this will return you to the TIFF driver used in Pro 12.5.

------------------------------
Sam Roberts
Engineer, MapInfo Pro Advanced (Raster)
Australia
------------------------------

Original Message:
Sent: 01-22-2020 11:47
From: Michel Li
Subject: Loading Raster Images is slow

I am trying to add 61 raster images in the map window and it is very fast in mapinfo 12.5 (18 seconds) but very slow in 2019 (1 minute 7 seconds). Does anyone know the reason? Here my codes.

Sub Imagery_Render(ByVal tableName as String, ByVal zoomMin as Float, ByVal zoomMax as Float)
       Dim windowId as String
       Select TabFile from tableName Into tblTifFiles
       Set Event Processing Off
       Fetch First from tblTifFiles
           windowId = UI_GetMapWindowID()
           Do While NOT EOT(tblTifFiles)
                Dim tabFile, name as String
                tabFile = tblTifFiles.TabFile
                Open Table tabFile Interactive
                name = TableInfo(NumTables(), TAB_INFO_NAME)
                Add Map Layer name Position 5
                Set Map Window windowId  Layer 5 Zoom (zoomMin, zoomMax) Units "mi" On Display Off
               Fetch Next from tblTifFiles
          Loop
     Set Event Processing On

Close Table tblTifFiles
End Sub

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

Sam,

I changed the options you told me and unfortunately it did not help. It takes the a long time to load the 61 images. Did I miss any steps?
See screen below.






------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

Original Message:
Sent: 01-24-2020 00:14
From: Sam Roberts
Subject: Loading Raster Images is slow

If Pro 2019, when you load a TIFF file for the first time, it will probably create an overview cache which is stored in a PPRC file with the TIFF. This takes a little time and so the first time you load the TIFF, it will be slower. The next time you open the TIFF the PPRC file will already be present and so it will be faster as it does not need to make it again.

If your TIFF files are in a read-only directory (for example if they are on a DVD) then the PPRC file cannot be stored. It will be kept as a temporary file that will be deleted when you close the TIFF. This will cause it to be slow each time you open the TIFF because the PPRC is created every time.

There are other settings which have an impact on this behaviour. In the backstage area under Options and MapInfo Pro Raster Preferences, there is a setting under "Display" called "Generate Raster Overview Cache" that can modify this behaviour.

If you really want it to behave like 12.5, then in the same preferences dialog, in the "Raster Formats" page, you can disable the TIFF driver (both Native and GDAL) and this will return you to the TIFF driver used in Pro 12.5.

------------------------------
Sam Roberts
Engineer, MapInfo Pro Advanced (Raster)
Australia

Original Message:
Sent: 01-22-2020 11:47
From: Michel Li
Subject: Loading Raster Images is slow

I am trying to add 61 raster images in the map window and it is very fast in mapinfo 12.5 (18 seconds) but very slow in 2019 (1 minute 7 seconds). Does anyone know the reason? Here my codes.

Sub Imagery_Render(ByVal tableName as String, ByVal zoomMin as Float, ByVal zoomMax as Float)
       Dim windowId as String
       Select TabFile from tableName Into tblTifFiles
       Set Event Processing Off
       Fetch First from tblTifFiles
           windowId = UI_GetMapWindowID()
           Do While NOT EOT(tblTifFiles)
                Dim tabFile, name as String
                tabFile = tblTifFiles.TabFile
                Open Table tabFile Interactive
                name = TableInfo(NumTables(), TAB_INFO_NAME)
                Add Map Layer name Position 5
                Set Map Window windowId  Layer 5 Zoom (zoomMin, zoomMax) Units "mi" On Display Off
               Fetch Next from tblTifFiles
          Loop
     Set Event Processing On

Close Table tblTifFiles
End Sub

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

By removing support for TIFF files by both the native driver and the GDAL driver, you ought to ensure that the TIFF files are loaded by the old Pro drivers.

Another possibility is that the system is being forced to compute some statistics for each of the TIFF files when you open them. Statistics are cached in the GHX file but only if they are computed in full for the base resolution level. This does not happen automatically so when you open a raster it may compute some approximate statistics in order to render the data. This takes a little time and may slow down the loading of many rasters.

If you want this investigated further I suggest you contact support, provide them with your data and workspaces etc and they can investigate.

------------------------------
Sam Roberts
Engineer, MapInfo Pro Advanced (Raster)
Australia
------------------------------

Original Message:
Sent: 01-24-2020 11:07
From: Michel Li
Subject: Loading Raster Images is slow

Sam,

I changed the options you told me and unfortunately it did not help. It takes the a long time to load the 61 images. Did I miss any steps?
See screen below.

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX

Original Message:
Sent: 01-24-2020 00:14
From: Sam Roberts
Subject: Loading Raster Images is slow

If Pro 2019, when you load a TIFF file for the first time, it will probably create an overview cache which is stored in a PPRC file with the TIFF. This takes a little time and so the first time you load the TIFF, it will be slower. The next time you open the TIFF the PPRC file will already be present and so it will be faster as it does not need to make it again.

If your TIFF files are in a read-only directory (for example if they are on a DVD) then the PPRC file cannot be stored. It will be kept as a temporary file that will be deleted when you close the TIFF. This will cause it to be slow each time you open the TIFF because the PPRC is created every time.

There are other settings which have an impact on this behaviour. In the backstage area under Options and MapInfo Pro Raster Preferences, there is a setting under "Display" called "Generate Raster Overview Cache" that can modify this behaviour.

If you really want it to behave like 12.5, then in the same preferences dialog, in the "Raster Formats" page, you can disable the TIFF driver (both Native and GDAL) and this will return you to the TIFF driver used in Pro 12.5.

------------------------------
Sam Roberts
Engineer, MapInfo Pro Advanced (Raster)
Australia

Original Message:
Sent: 01-22-2020 11:47
From: Michel Li
Subject: Loading Raster Images is slow

I am trying to add 61 raster images in the map window and it is very fast in mapinfo 12.5 (18 seconds) but very slow in 2019 (1 minute 7 seconds). Does anyone know the reason? Here my codes.

Sub Imagery_Render(ByVal tableName as String, ByVal zoomMin as Float, ByVal zoomMax as Float)
       Dim windowId as String
       Select TabFile from tableName Into tblTifFiles
       Set Event Processing Off
       Fetch First from tblTifFiles
           windowId = UI_GetMapWindowID()
           Do While NOT EOT(tblTifFiles)
                Dim tabFile, name as String
                tabFile = tblTifFiles.TabFile
                Open Table tabFile Interactive
                name = TableInfo(NumTables(), TAB_INFO_NAME)
                Add Map Layer name Position 5
                Set Map Window windowId  Layer 5 Zoom (zoomMin, zoomMax) Units "mi" On Display Off
               Fetch Next from tblTifFiles
          Loop
     Set Event Processing On

Close Table tblTifFiles
End Sub

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------

------------------------------
Michel Li
Programmer
GEOSEARCH LLP
Austin TX
------------------------------