projpicker 0.1.4.dev4

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. This project was motivated by a GRASS GIS feature request. It is a work in progress; join discussions. See also the command-line and API documentation.

Branches

main

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

rtree-oop

The rtree-oop branch utilizes the rtree module in an object-oriented programming (OOP) way. This branch supports point intersection. The rtree spatial indexing may not be able to handle reversed west and east longitudinal boundaries that cross the antimeridian.

Requirements

Tested with proj.db from pyproj 3.1.0 in Python 3.7.2

Requires the PROJ database (e.g., /usr/share/proj/proj.db) only for recreating the provided projpicker.db, if you want, and the following standard modules:

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

Installation

• GitHub repository
• Python package

pip3 install projpicker

# or if you're not a root
pip3 install --user projpicker

# to install development versions
pip3 install --pre projpicker

# or if you're not a root
pip3 install --pre --user projpicker

Creating the ProjPicker database

This step is optional because projpicker.db generated from PROJ 7.2.1 is shipped with the module by default. Run this step only when you want to recreate this database from your version of PROJ.

From the shell,

projpicker -c

From Python,

import projpicker as ppik
ppik.create_projpicker_db()

Supported coordinate formats

The following geometry file points.txt contains 11 identical points:

################################
# decimal degrees and separators
################################
34.2348,-83.8677		# comma
34.2348		-83.8677	# whitespace

####################################################
# degree, minute, and second symbols
# degree: ° (U+00B0, °, alt+0 in xterm), o, d
# minute: ' (U+0027, '), ′ (U+2032, ′), m
# second: " (U+0022, "), ″ (U+2033, ″),
#	  '' (U+0027 U+0027, ' '), s
####################################################
34.2348°	-83.8677°	# without minutes, seconds, and [SNWE]
34°14.088'	-83°52.062'	# without seconds and [SNWE]
34°14'5.28"	-83°52'3.72"	# without [SNWE]
34.2348°N	83.8677°W	# without minutes and seconds
34°14.088'N	83°52.062'W	# without seconds
34°14'5.28"N	83°52'3.72"W	# full
34°14′5.28″N	83°52′3.72″W	# full using U+2032 and U+2033
34o14'5.28''N	83o52'3.72''W	# full using o' and ''
34d14m5.28sN	83d52m3.72sW	# full using dms

Running projpicker -p -i points.txt will generate:

[[34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677],
 [34.2348, -83.8677]]

Querying points

From the shell,

# read latitude and longitude separated by a comma or whitespaces from
# arguments
projpicker 34.2348,-83.8677 "33.7490  84.3880W"

# read latitude and longitude from stdin
projpicker <<EOT
# query points
34.2348		83°52'3.72"W	# UNG Gainesville Campus
33°44'56.4"	-84.3880	# Atlanta
EOT

From Python,

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

Querying polylines or polygons

From the shell,

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

# read latitude,longitude from stdin
projpicker -g poly <<EOT
# poly 1
# south-west corner
10S,0
10,0	# north-west corner
	# this comment-only line doesn't start a new poly
# north-east corner
10	10
# north-west corner
10	0
poly 2	# "poly 2" is neither a comment nor a point, so we start a new poly
10	20
30	40
EOT

From Python,

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

Querying bounding boxes

From the shell,

# read south,north,west,east from arguments
projpicker -g bbox 0,0,10,10 20,20,50,50

# read south,north,west,east from stdin
projpicker -g bbox <<EOT
# region 1
0	0	10	10

# region 2
20	20	50	50
EOT

From Python,

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

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 (client-only)
   • Desktop
2. Missing projection information? Let's find it using coordinates in latitude and longitude.
3. CRS hints
   • Crowdsourcing agency and product information?

Versioning

N(.N)*[{a|b|rc}N][.postN][.devN]

• PEP 440
• {a|b|rc|.dev}N towards and .postN away from the release
• Not fully compatible with semantic versioning
• Not using build numbers marching away from or towards a release, but check this interesting comment.

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/>.