Mercurial > gemma
view pkg/models/reproject.go @ 5095:e21cbb9768a2
Prevent duplicate fairway areas
In principal, there can be only one or no fairway area at each point
on the map. Since polygons from real data will often be topologically
inexact, just disallow equal geometries. This will also help to
avoid importing duplicates with concurrent imports, once the history
of fairway dimensions will be preserved.
author | Tom Gottfried <tom@intevation.de> |
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date | Wed, 25 Mar 2020 18:10:02 +0100 |
parents | d753ce6cf588 |
children | 1222b777f51f |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2018 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> package models import ( "context" "database/sql" ) const reprojectSQL = ` SELECT ST_X(p), ST_Y(p) FROM ST_Transform(ST_SetSRID(ST_MakePoint($1, $2), $3::integer), $4::integer) AS p` type Reprojector struct { stmt *sql.Stmt FromEPSG uint32 ToEPSG uint32 } func NewReprojector( ctx context.Context, conn *sql.Conn, fromEPSG, toEPSG uint32, ) (*Reprojector, error) { stmt, err := conn.PrepareContext(ctx, reprojectSQL) if err != nil { return nil, err } return &Reprojector{ stmt: stmt, FromEPSG: fromEPSG, ToEPSG: toEPSG, }, nil } func (r *Reprojector) Close() error { if s := r.stmt; s != nil { r.stmt = nil return s.Close() } return nil } func (r *Reprojector) Reproject( ctx context.Context, x, y float64, ) (v, w float64, err error) { err = r.stmt.QueryRowContext(ctx, x, y, r.FromEPSG, r.ToEPSG).Scan(&v, &w) return }