projpicker 0.1.2

ProjPicker (projection picker) allows the user to select all projections whose extent completely contains given points, polylines, polygons, and bounding boxes. The goal is to make it easy and visual to select a desired projection by location.

ProjPicker

ProjPicker (projection picker) allows the user to select all projections whose extent completely contains given points, polylines, polygons, and bounding boxes. The goal is to make it easy and visual to select a desired projection by location.

It is a work in progress. Read a related feature request for GRASS and join discussions.

The single Python script projpicker.py provides the CLI and API for ProjPicker.

The rtree-oop branch utilizes the rtree module in an object-oriented programming (OOP) way. This branch supports point intersection.

Requirements

Tested with PROJ 7.2.1 in Python 3.7.2

Requires the PROJ database (e.g., /usr/share/proj/proj.db) and the following standard modules:

• argparse
• os
• sys
• sqlite3
• re
• json
• pprint
• math

Command-line usage

usage: projpicker.py [-h] [-c] [-O | -a] [-d PROJPICKER_DB] [-p PROJ_DB]
                     [-g {point,poly,bbox}] [-q {and,or,all}]
                     [-f {plain,pretty,json}] [-n] [-s SEPARATOR] [-i INPUT]
                     [-o OUTPUT]
                     [geometry [geometry ...]]

ProjPicker finds coordinate reference systems (CRSs) whose bounding box
contains given geometries; visit https://github.com/HuidaeCho/projpicker for
more details

positional arguments:
  geometry              query geometry in latitude,longitude (point and poly)
                        or s,n,w,e (bbox); points, points in a poly, or bboxes
                        are separated by a space and polys are separated by
                        any non-coordinate character such as a comma

optional arguments:
  -h, --help            show this help message and exit
  -c, --create          create ProjPicker database
  -O, --overwrite       overwrite output files; applies to both projpicker.db
                        and query output file
  -a, --append          append to output file if any; applies only to query
                        output file
  -d PROJPICKER_DB, --projpicker-db PROJPICKER_DB
                        projPicker database path (default: projpicker.db); use
                        PROJPICKER_DB environment variable to skip this option
  -p PROJ_DB, --proj-db PROJ_DB
                        proj database path (default: /usr/share/proj/proj.db);
                        use PROJ_DB or PROJ_LIB (PROJ_LIB/proj.db) environment
                        variables to skip this option
  -g {point,poly,bbox}, --geometry-type {point,poly,bbox}
                        geometry type (default: point)
  -q {and,or,all}, --query-mode {and,or,all}
                        query mode for multiple points (default: and); use all
                        to list all bboxes and ignore geometries
  -f {plain,pretty,json}, --format {plain,pretty,json}
                        output format
  -n, --no-header       do not print header for plain output format
  -s SEPARATOR, --separator SEPARATOR
                        separator for plain output format (default: comma)
  -i INPUT, --input INPUT
                        input geometries path (default: stdin); use - for
                        stdin; not used if geometries are given as arguments
  -o OUTPUT, --output OUTPUT
                        output path (default: stdout); use - for stdout

Creating the ProjPicker database

From shell,

projpicker.py -c

From Python,

import projpicker as ppik
ppik.create_projpicker_db()

Querying points

From shell,

# read latitude,longitude from arguments
projpicker.py 34.2348,83.8677 33.7490,84.3880

# read latitude,longitude from stdin
projpicker.py <<EOT
34.2348,83.8677
33.7490,84.3880
EOT

From Python,

import projpicker as ppik
bbox = ppik.listify_bbox(ppik.query_points([[34.2348, 83.8677],
					    [33.7490, 84.3880]]))

Querying polylines/polygons

From shell,

# read latitude,longitude from arguments
projpicker.py -g poly -- -10,0 10,0 10,10 10,0 , 10,20 30,40

# read latitude,longitude from stdin
projpicker.py -g poly <<EOT
# poly 1
-10,0
10,0
10,10
10,0

# poly 2
10,20
30,40
EOT

From Python,

import projpicker as ppik
bbox = ppik.listify_bbox(ppik.query_polys([[[-10, 0], [10, 0],
					    [10, 10], [10, 0]],
					   [[10, 20], [30, 40]]]))

Querying bboxes

From shell,

# read s,n,w,e from arguments
projpicker.py -g bbox 0,0,10,10 20,20,50,50

# read s,n,w,e from stdin
projpicker.py -g bbox <<EOT
0,0,10,10
20,20,50,50
EOT

From Python,

import projpicker as ppik
bbox = ppik.listify_bbox(ppik.query_bboxes([[0, 0, 10, 10], [20, 20, 50, 50]]))

TODO

1. GUI
   • ArcGIS Pro Toolbox for ArcGIS users including IESA students? Will be easier to implement because ArcGIS Pro provides nice pencil tools and mapping functionalities. We'll be able to see almost immediate returns.
   • Web
   • Desktop
2. CRS hints
   • Crowdsourcing agency and product information?

Sponsor

This project is kindly funded by the Institute for Environmental and Spatial Analysis (IESA) at the University of North Georgia (UNG).

License

Copyright (C) 2021 Huidae Cho and Owen Smith

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <https://www.gnu.org/licenses/>.