Convert grid lines to polygons

Bud — Fri, 17 Jun 2022 02:12:02 GMT

I have a SQL script that quickly generates grid line features, for testing purposes, using whatever grid dimensions I need: Generate SDO_GEOMETRY grid using SQL.

The result is a spatial view (can be easily exported as a feature class).
I'm aware that there are GP tools that can generate grids too. But for my use case, I like this SQL option.
The lines are split at the intersections. So this 10x10 grid has 220 lines:

Question:

Is there a way to convert the grid lines to polygons? (i.e. a polygon for each grid cell)

I tried creating a polygon envelope FC and then I looked for a GP tool that could split the polygon via multiple lines. But I haven't found a GP tool that can do that yet.

Advanced license: ArcGIS Pro 2.6.8 and ArcMap 10.7.1. Oracle 18c EGDB.

Re: Convert grid lines to polygons

Bud — Fri, 17 Jun 2022 23:24:32 GMT

I suppose one way to do it would be to modify the existing query:

Details:

(1) Keep only the horizontal lines. Exclude the vertical lines.

where
    startpoint_y = endpoint_y

Here's a sample horizontal line:

  OBJECTID STARTPOINT_X STARTPOINT_Y ENDPOINT_X ENDPOINT_Y SHAPE         
---------- ------------ ------------ ---------- ---------- --------------
       219            0            0          0          1 [SDO_GEOMETRY]

(2) Add an additional outer query where we generate 5 vertices (a polygon) from the existing 2 vertices (from the original horizontal line):

startpoint_x, --vertex 1 (original vertex from the horizontal line)
startpoint_y,

endpoint_x,   --vertex 2 (original vertex from the horizontal line)
endpoint_y,

endpoint_x,   --vertex 3
endpoint_y+1,

startpoint_x, --vertex 4
startpoint_y+1,

startpoint_x, --vertex 5 (same as vertex 1) https://gis.stackexchange.com/q/433083/62572
startpoint_y,

(3) Just like with the lines query, construct a polygon geometry by concatenating the coordinates together into WKT.

sdo_geometry('polygon(('||startpoint_x||' '||startpoint_y||', '||endpoint_x||' '||endpoint_y||', '||endpoint_x||' '||(endpoint_y+1)||', '||startpoint_x||' '||(startpoint_y+1)||', '||startpoint_x||' '||startpoint_y||'))',26917) as shape

(4) Now, the coordinates look like this (the vertex direction is counterclockwise; vertex 1 and 5 are both 0,0):

(5) This is what the full query looks like:

--create or replace view sdo_geom_grid_polygons_vw as (
select
                 objectid,
                 'polygon(('||startpoint_x||' '||startpoint_y||', '||endpoint_x||' '||endpoint_y||', '||endpoint_x||' '||(endpoint_y+1)||', '||startpoint_x||' '||(startpoint_y+1)||', '||startpoint_x||' '||startpoint_y||'))'        as wkt,
    sdo_geometry('polygon(('||startpoint_x||' '||startpoint_y||', '||endpoint_x||' '||endpoint_y||', '||endpoint_x||' '||(endpoint_y+1)||', '||startpoint_x||' '||(startpoint_y+1)||', '||startpoint_x||' '||startpoint_y||'))',26917) as shape
from 
    (

with dimension as (
    select 0 as point from dual
        union all 
    select level
    from dual
    connect by level <= 10
), points as (
    select 
        a.point as startpoint, 
        b.point as endpoint,
        c.point as fixed
    from dimension a
    cross join dimension b
    cross join dimension c
    where b.point - a.point = 1
)
select
    cast(rownum as number(38,0)) as objectid,
    startpoint_x,
    startpoint_y,
    endpoint_x,
    endpoint_y
from
    (
    select
        startpoint as startpoint_x,
        fixed as startpoint_y,
        endpoint as endpoint_x,
        fixed as endpoint_y
    from points
        union all
    select
        fixed as startpoint_x,
        startpoint as startpoint_y,
        fixed as endpoint_x,
        endpoint as endpoint_y
    from points
    )
order by startpoint_x, startpoint_y, endpoint_x, endpoint_y    
)
where
    startpoint_y = endpoint_y --get horizontal lines only
--);

Re: Convert grid lines to polygons

DanPatterson — Fri, 17 Jun 2022 07:59:14 GMT

related - deja vu

oracle - Generate grid line coordinates using SQL - Stack Overflow

Re: Convert grid lines to polygons

Bud — Fri, 17 Jun 2022 08:13:14 GMT

Yeah, that's the source of my query. I mention it in the link in the original post.

Re: Convert grid lines to polygons

Maps-Berlin — Fri, 17 Jun 2022 08:39:56 GMT

The "feature to polygon" tool can do it no?

topic Re: Convert grid lines to polygons in ArcGIS Pro Questions

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