Thanks for the update, guys. I'm not ready to contribute yet.
In the meanwhile, the solution could be perhaps to convert GeoTiff to another format supported by Sedona. If anyone has had this use case before or has any idea, please share. Best, On Wed, 18 Jan 2023 at 09:47, Martin Andersson <[email protected]> wrote: > Hi, > > I think you are looking for something like this: > https://postgis.net/docs/RT_ST_Value.html > > The raster support in Sedona is very limited at the moment. The lack of a > proper raster type makes implementing st_value impossible. We had a brief > discussion about that recently. > https://lists.apache.org/thread/qdfcvxl6z5pb7m7ky5zsksyytyxqwv8c > > If you want to make a contribution and need some guidance, please let me > know! > > Br, > Martin Andersson > > Den ons 18 jan. 2023 kl 05:45 skrev Jia Yu <[email protected]>: > >> Hi Pedro, >> >> I got your point. Unfortunately, we don't have this function yet in >> Sedona. >> But we welcome anyone who want to contribute this to Sedona! >> >> Thanks, >> Jia >> >> On Tue, Jan 17, 2023 at 9:11 AM Pedro Mano Fernandes < >> [email protected]> >> wrote: >> >> > Hi all, >> > >> > Any clue? Or any documentation I can refer to? >> > >> > Here goes a dummy example to better explain myself: in QGIS I can click >> a >> > point (coordinates) of the geotiff and get the value in that point (in >> this >> > case 231 of Band 1). >> > >> > [image: image.png] >> > >> > Thanks, >> > >> > On Sun, 15 Jan 2023 at 16:17, Pedro Mano Fernandes < >> [email protected]> >> > wrote: >> > >> >> Hi Jia, >> >> >> >> Thanks for the fast response. >> >> >> >> With the regular spatial join I’ll get the array of data of the whole >> >> geotiff polygon. I was hoping to get the data element for specific >> >> coordinates inside that polygon. In other words: I guess the array of >> data >> >> corresponds to all the positions in the polygon, but I want to fetch >> >> specific positions. >> >> >> >> Thanks, >> >> >> >> On Sun, 15 Jan 2023 at 01:09, Jia Yu <[email protected]> wrote: >> >> >> >>> Hi Pedro, >> >>> >> >>> Once you use Sedona geotiff reader to read those geotiffs, you will >> get >> >>> a dataframe with the following schema: >> >>> >> >>> |-- image: struct (nullable = true) >> >>> | |-- origin: string (nullable = true) >> >>> | |-- Geometry: string (nullable = true) >> >>> | |-- height: integer (nullable = true) >> >>> | |-- width: integer (nullable = true) >> >>> | |-- nBands: integer (nullable = true) >> >>> | |-- data: array (nullable = true) >> >>> | | |-- element: double (containsNull = true) >> >>> >> >>> >> >>> You can use the following way to fetch the geometry column and perform >> >>> the spatial join; >> >>> >> >>> geotiffDF = geotiffDF.selectExpr("image.origin as >> >>> origin","ST_GeomFromWkt(image.geometry) as Geom", "image.height as >> height", >> >>> "image.width as width", "image.data as data", "image.nBands as bands") >> >>> geotiffDF.createOrReplaceTempView("GeotiffDataframe") >> >>> geotiffDF.show() >> >>> >> >>> More info can be found: >> >>> >> https://sedona.apache.org/1.3.1-incubating/api/sql/Raster-loader/#geotiff-dataframe-loader >> >>> >> >>> Thanks, >> >>> Jia >> >>> >> >>> On Sat, Jan 14, 2023 at 9:10 AM Pedro Mano Fernandes < >> >>> [email protected]> wrote: >> >>> >> >>>> Hi everyone! >> >>>> >> >>>> I'm trying to use elevation data in GeoTiff format. I understand how >> to >> >>>> load the dataset, as described in >> >>>> >> >>>> >> https://sedona.staged.apache.org/api/sql/Raster-loader/#geotiff-dataframe-loader >> >>>> . >> >>>> Now I'm wondering how to join this dataframe with another one that >> >>>> contains >> >>>> coordinates, in order to get the elevation data for those >> coordinates. >> >>>> >> >>>> Something along these lines: >> >>>> >> >>>> pointsDF >> >>>> .join(geotiffDF, ...) >> >>>> .select("lon", "lat", "geotiff_data") >> >>>> >> >>>> Are there any examples or documentation I can follow to accomplish >> this? >> >>>> >> >>>> Thanks, >> >>>> >> >>>> -- >> >>>> Pedro Mano Fernandes >> >>>> >> >>> -- >> >> Pedro Mano Fernandes >> >> >> > >> > >> > -- >> > Pedro Mano Fernandes >> > >> > > > -- > Hälsningar, > Martin > -- Pedro Mano Fernandes
