Hi,
I converted canadian .DEM files from geobase.ca with the read_dem.exe utility. But cannot open the output BSQ file with sbuilder. What's the problem ?
thank you
Joel
Cannot import BSQ in Sbuilder
Hi,
Please ZIP one BSQ and send to luis@ptsim.com
Please tell me what I should expect. Number of rows and number of Columns. This is an extra information that is needed or you cannot open these files. A BSQ of 10,000 altitudes could refer to 100 x 100
altitudes, 1,000 x 10 or any other combination.
Luis
Please ZIP one BSQ and send to luis@ptsim.com
Please tell me what I should expect. Number of rows and number of Columns. This is an extra information that is needed or you cannot open these files. A BSQ of 10,000 altitudes could refer to 100 x 100
altitudes, 1,000 x 10 or any other combination.
Luis
Hi,
BSQ Tools, as I call them in SBuilder, can only be used with 1 Arc Sec data or 3 Arc Sec data.
In 1 Arc Sec data, you have 1 data point every second or 60 points every minute or 3600 points every degree. A file covering 1 degree by 1 degree will have 3601 x 3601 points.
In 3 Arc Sc data, you have 1 data point every 3 seconds, 20 points every minute or 1200 points every degree.
You can merge, interpolate, filter, etc, if you are using BSQ files created with SBuilder from HGT or DTED2 files.
If your BSQ was created elsewhere and has a different resolution (not 1 ArcS or 3 ArcS) you can still use it. You do a BSQ > Bitmap conversion. Then you can use the bitmap to generate mesh.
You need to know the number of ROWS and the number of COLS of the BSQ. This is normally known from the context where you got the file. With the ROWS and the COLS you simply convert the file to a bitmap.
Then you also need to create a TXT file with the same base name of the bitmap so that you can use the automatic calibration implemented in SBuilder 2.04. If the bitmap is MY_BITMAP.BMP, you create a file MY_BITMAP.TXT with the following 5 lines:
[GEOGRAPHIC]
North=40
South=39
West=-80
East=-79
In the example the file covers 1 degree by 1 degree! Say that you only know the NW corner, the latitude spacing, the longitude spacing, the rows and the columns. For example:
North=40
West=-80
DeltaLat = 0.75" = 0.75 / 3600 = 2,083333333333333e-4
DeltaLon = 0.75" = 0.75 / 3600 = 2,083333333333333e-4
Rows=1201
Columns=1201
The spacings were converted from seconds to degrees!
How to calculate South and East? Here are the answers:
South = North - ( Rows - 1 ) x DeltaLat = 39.75
East = West + ( Cols - 1 ) x DeltaLon = -79.75
If you have, in addition to the above data, the East and the South borders it will be useful to confirm if the calculations are correct. For the example the TXT file will be:
[GEOGRAPHIC]
North=40
South=39.75
West=-80
East-79.75
Finally if the border coordinates are in a different projection or datum system, you can use SBuilder Coordinates tool to convert into the Geographic WGS84 system.
Regards, Luis
BSQ Tools, as I call them in SBuilder, can only be used with 1 Arc Sec data or 3 Arc Sec data.
In 1 Arc Sec data, you have 1 data point every second or 60 points every minute or 3600 points every degree. A file covering 1 degree by 1 degree will have 3601 x 3601 points.
In 3 Arc Sc data, you have 1 data point every 3 seconds, 20 points every minute or 1200 points every degree.
You can merge, interpolate, filter, etc, if you are using BSQ files created with SBuilder from HGT or DTED2 files.
If your BSQ was created elsewhere and has a different resolution (not 1 ArcS or 3 ArcS) you can still use it. You do a BSQ > Bitmap conversion. Then you can use the bitmap to generate mesh.
You need to know the number of ROWS and the number of COLS of the BSQ. This is normally known from the context where you got the file. With the ROWS and the COLS you simply convert the file to a bitmap.
Then you also need to create a TXT file with the same base name of the bitmap so that you can use the automatic calibration implemented in SBuilder 2.04. If the bitmap is MY_BITMAP.BMP, you create a file MY_BITMAP.TXT with the following 5 lines:
[GEOGRAPHIC]
North=40
South=39
West=-80
East=-79
In the example the file covers 1 degree by 1 degree! Say that you only know the NW corner, the latitude spacing, the longitude spacing, the rows and the columns. For example:
North=40
West=-80
DeltaLat = 0.75" = 0.75 / 3600 = 2,083333333333333e-4
DeltaLon = 0.75" = 0.75 / 3600 = 2,083333333333333e-4
Rows=1201
Columns=1201
The spacings were converted from seconds to degrees!
How to calculate South and East? Here are the answers:
South = North - ( Rows - 1 ) x DeltaLat = 39.75
East = West + ( Cols - 1 ) x DeltaLon = -79.75
If you have, in addition to the above data, the East and the South borders it will be useful to confirm if the calculations are correct. For the example the TXT file will be:
[GEOGRAPHIC]
North=40
South=39.75
West=-80
East-79.75
Finally if the border coordinates are in a different projection or datum system, you can use SBuilder Coordinates tool to convert into the Geographic WGS84 system.
Regards, Luis