[postgis-users] screen copy with postgis

[Tumasgiu Rossini]

I don't think there is a function to transform text into polygon
in postgis, though it can be feasible.

Looks like you gonna need to code a little more.

If you decide to stick to C#, you could use things like
dotspatial or sharpmap.
You could also just use the Npgqsl ADO connector to avoid
too many depedencies and do the math yourself.
Npgsql has built-in types for handling postgis geometries.

2017-02-23 8:58 GMT+01:00 Olivier Leprêtre <o.lepretre at gmail.com>:

> Hi,
>
>
>
> Thanks for this answer Thomas, you confirm what I guessed also. Before
> considering this way, I had a look about attributes and didn't find how I
> could create raster texts layer, to display gid or other information. So I
> wonder if I should better not carrying on with Postgis for that but try
> another way...
>
>
>
> Olivier
>
>
>
>
>
> *De :* postgis-users [mailto:postgis-users-bounces at lists.osgeo.org] *De
> la part de* Tumasgiu Rossini
> *Envoyé :* mercredi 22 février 2017 22:56
> *À :* PostGIS Users Discussion
> *Objet :* Re: [postgis-users] screen copy with postgis
>
>
>
> Hi,
>
> I'm not sure there is a function that can burns geometries on an existing
>
> raster.
>
> So I guess you will need to create a raster for each "layer" you want to
>
> draw (e.g. the polygons, the boundaries...) and merge them into a
>
> final raster using st_mapalgebra.
>
>
>
> 2017-02-22 21:48 GMT+01:00 Olivier Leprêtre <o.lepretre at gmail.com>:
>
> Hi,
>
>
>
> I'm trying to do a "screen copy" from a set of polygons. So I thought that
> I could use St_AsRaster and St_AsJpeg as follow, with the selection of two
> poly.
>
>
>
> SELECT ST_AsJPEG(ST_AsRaster(st_collect((Select geom from poly where
> gid=605530),(Select geom from poly where gid=605533)),1000,1000,
> ARRAY['8BUI', '8BUI', '8BUI'], ARRAY[255,255,255],
> ARRAY[0,0,0],null,null,0,0,true))
>
>
>
> I load the result in a C# app which is in charge to save it as a file.
> This "works" but I'm loosing the boundaries (tha't to say the red lines in
> the image below).
>
>
>
> 1)    Is there a way to keep those boundaries ?
>
> 2)    As I have other layers, like texts, will it be possible to make
> them appear also, like a screen copy ?
>
>
>
> In other words, more simply, am I on the right way or should I think to a
> completely different solution ?
>
>
>
> Thanks,
>
>
>
> Olivier
>
>
>
> [image: cid:image001.jpg at 01D28DB2.F9256BC0]
>
>
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