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 >
