topic Re: What is the standart for BAG creation? in GIS for Hydrographic Surveying Questions

What is the standart for BAG creation?

AnzhelikaKamza3 — Fri, 20 May 2016 07:50:23 GMT

Hello Dear GIS users.

Could you please advise with question regarding BAG file?

We are starting work with BAG format. We have Fledermaus and ArcGIS. Input data is x, y, z gridded file (0.5x0.5 meters). We calculate uncertainty using special order, after that export to BAG. When we compare in ArcGIS GeoTIFF from Fledermaus and BAG from Fledermaus we can see shift between them about 60-65 cm (See attached file).
What is the standart for BAG creation? I checked Fledermaus and CARIS software. And I have 2 different BAG files. Support team from QPS and CARIS tell me that is different method of grid creation. I can't understand why we have this difference and shifts, as I understand BAG file is format to exhange data between software.

Look forward

regards,

Anzhelika

Re: What is the standart for BAG creation?

DanPatterson_Retired — Fri, 20 May 2016 12:26:37 GMT

either your extents are different or they use a different method of referencing the grid. esri uses the center of the cell to denote position when creating rasters, other software may use a different location. In any event, they seem to be shifted by 1/2 cell size in the x and maybe 1 in the y direction. You will need to confirm the extents and cell sizes. Also, in arcmap, it is wise to use a snap raster to ensure that cell edges etc align properly

Re: What is the standart for BAG creation?

AnzhelikaKamza3 — Tue, 24 May 2016 09:35:10 GMT

Hello Dan,

I don't understand how to confirm extend in ArcGIS& Is it special tool for do this?

regards,

Anzhelika

Re: What is the standart for BAG creation?

DanPatterson_Retired — Tue, 24 May 2016 09:45:46 GMT

right-click on a layer, select properties to bring up the layer properties and all the information is there ... check the Source tab.

Repeat for all layers since ArcMap does projection on the fly to make things 'look' aligned when they may in fact be in different coordinate systems.

Re: What is the standart for BAG creation?

AnzhelikaKamza3 — Tue, 24 May 2016 10:40:20 GMT

I test tthat you recomended. It is take extent and data from source that I show in Source tab.

Is it possible to change extent using another raster?

Re: What is the standart for BAG creation?

DanPatterson_Retired — Tue, 24 May 2016 10:47:51 GMT

if they are in the same coordinate system, otherwise you are talking about a projection

Re: What is the standart for BAG creation?

AnzhelikaKamza3 — Tue, 24 May 2016 10:54:19 GMT

2 rasters in the same projection.

Re: What is the standart for BAG creation?

DanPatterson_Retired — Tue, 24 May 2016 11:02:54 GMT

not sure why you want to use a different extent, but I think you are wanting to Shift—Help | ArcGIS for Desktop the raster

Re: What is the standart for BAG creation?

AnzhelikaKamza3 — Wed, 25 May 2016 10:50:47 GMT

Thank you very much.

Re: What is the standart for BAG creation?

DanPatterson_Retired — Wed, 25 May 2016 13:06:34 GMT

Anzhelika, please close this thread if it was answered so others know a solution was arrived at.

Re: What is the standart for BAG creation?

AnzhelikaKamza3 — Thu, 26 May 2016 03:07:18 GMT

Hello Dan,

I am still don't have answer for main question "What is the standart for BAG format". How we can use it as exchange file if different software create different output file.

Re: What is the standart for BAG creation?

DanPatterson_Retired — Thu, 26 May 2016 13:09:10 GMT

The BAG format is within the bathymetry data description. A good starting point would be the help files beginning at Essential bathymetric vocabulary—Help | ArcGIS for Desktop

within the various links the ISO standard is given amongst other things.