Unable to change values

[tedrigby]

Hi

I am running W10 and QGIS 3.16.4 and recently installed serval to modify some cells in my ascii grid topography file. I have tried all of the recommended selection and reset approaches mentioned in the manual but although the blue circle appears as if it is changing the elevation value - applying the probe to check afterward shows no change. Is there a problem or have I just not approached selection/adjustment in the right order? It is as if the ascii grid file is not available for writing.

Many thanks

Ted Rigby

[erpas]

Hi Tom,

yep, the ASCII grid is a read-only format: https://gdal.org/drivers/raster/aaigrid.html#raster-aaigrid
Try to convert it to another format, for example TIF, and you should be able to modify it.

Kind Regards,

Radek Pasiok

[tedrigby]

Thanks Radek I tried converting to geotiff and yes serval then worked fine. Thanks for your speedy response. Is there some reason why QGIS/Serval does not support writing to an ascii grid – seems odd given the wide use of ascii grid formats in civil engineering as an elevation layer. I am a split Global Mapper – QGIS user and can easily export a non ascii raster to ascii grid format in Global Mapper so was not expecting problems writing to a grid in QGIS/Serval? Ted From: Radek Pasiok ***@***.***> Sent: 16 March, 2021 7:40 PM To: lutraconsulting/serval ***@***.***> Cc: Ted ***@***.***>; Author ***@***.***> Subject: Re: [lutraconsulting/serval] Unable to change values (#28) Hi Tom, yep, the ASCII grid is a read-only format: https://gdal.org/drivers/raster/aaigrid.html#raster-aaigrid Try to convert it to another format, for example TIF, and you should be able to modify it. Kind Regards, Radek Pasiok — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#28 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ADBHDDUNY43SE6UFARBYRXDTD4KPBANCNFSM4ZFPTLNA>.

[erpas]

QGIS depends on GDAL in it, so it would be question for its developers.