[Qgis-user] vector point grid to raster grid -- pixel size does not work

Tue May 12 19:00:07 PDT 2020

Hi, 

Thanks for helping. -- Thanks to you and Chris Hermansen I got a result, but it could be better. 

For the records, a short explanation:

*****
Well, I checked the properties, jgd2011 is in Meters, the raster is said to be 5m. In the official Japanese viewer, which creates a beautiful raster image without white pixels, the pixels are exactly 5m*5m. 

Today I tried the export to .xyz since the shapefile looked ugly, and after realising that the Japanese xyz is indeed yxz, everything looked fine, and I could store it in a Geopackage. But the grid is now 5,276m * 6,146m. But it fits well on top of the basemap. The basemap is of the same special Japanese GML format, but QGIS could read it all without problem. I do not understand why QGIS does not read the point data from  the GML fille, but that is an aside, I am amazed by what QGIS actually can do. 

From the Geopackage I could rasterize. It is as Chris Hermansen said, thanks. Unfortunately, I did not get it done from the shapefiles, they always looked weird or like nothing, even with identical settings. But the geopackages from xyz tiles are fine. 

For resolution, I chose georeferenced units as Chris suggested, and since the measurement tool got some different length, I put it to 5,276m by 6,146m. A 5m by 5m resolution created a weird layer with horizontally expanding white pixels.

It seems that tweaking with the resolution might lead to an even better result, but for the time being, it is OK as it is. 
*****

Thanks again, 
Maria

> Am 13.05.2020 um 00:12 schrieb Nicolas Cadieux <nicolas.cadieux at archeotec.ca>:
> 
> Hi,
> 
> What is the resolution of the jgd20011 raster?  Look in the layer properties.  Once you are done, use a base map, like something from the quickmap plugin and check the results and the georeferencing.  Pixels will be big if you zoom on them.
> 
> Nicolas Cadieux
> Ça va bien aller!
> 
>> Le 12 mai 2020 à 07:24, Priv.-Doz. Dr. Maria Shinoto <maria.shinoto at zaw.uni-heidelberg.de> a écrit :
>> 
>> Hi, 
>> 
>> I am having problems to set up the parameters for Raster > Convert > Rasterize Vector to Raster
>> 
>> My basic map is JGD2011 / Japan Plnae Rectangular CS II, and I downloaded an xml file JPGIS/GML format, that had to be converted to shapefile in a special application. 
>> 
>> Now I have the points as a grid with approximately 5m distance and want to convert them to Raster, since this is what I want to use as DEM for analyses. 
>> 
>> Everything works, but the pixel are extremely largen, not 5m.
>> 
>> I set the units to pixel, and since it is 5m mesh (from 0.2 seconds), I was told to use 0.000056 for horizontal and vertical resolution, but I do not know what I am doing there, and I do not find any similar application in tutorials, handbooks and books, the options in QGIS documentation do not really help. 
>> 
>> Can anybody guide me to the correct value? Or to another flaw in my thinking? 
>> 
>> Thanks a lot, 
>> Maria
>> 
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