{
"cells": [
{
"cell_type": "markdown",
"id": "2ac0e74d",
"metadata": {},
"source": [
"# Using Exotic Map Projections: `use_crs=\"provided\"`\n",
"\n",
"Value \"provided\" tells Lets-Plot that the input GeoDataframe already contains coordinates in the desired CRS and should not be reprojected any further.\n",
"\n",
"This is a workaround for the case when the desired CRS is not naturally supported by Lets-Plot.\n",
"\n",
"For example, if you try to use the **Robinson** projection (EPSG:54030): `use_crs=\"EPSG:54030\"`, then Lets-Plot will return an error: \n",
"> CRSError: Invalid projection: EPSG:54030: (Internal Proj Error: proj_create: crs not found)\n",
"\n",
"Let's see how can we still plot a map in the **Robinsons** projection in Lets-Plot."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "8ab5b1ed",
"metadata": {
"execution": {
"iopub.execute_input": "2024-04-26T12:01:13.376836Z",
"iopub.status.busy": "2024-04-26T12:01:13.376836Z",
"iopub.status.idle": "2024-04-26T12:01:14.451546Z",
"shell.execute_reply": "2024-04-26T12:01:14.451546Z"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"The geodata is provided by © OpenStreetMap contributors and is made available here under the Open Database License (ODbL).\n"
]
}
],
"source": [
"from lets_plot import *\n",
"from lets_plot.geo_data import *"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "b0b9825c",
"metadata": {
"execution": {
"iopub.execute_input": "2024-04-26T12:01:14.451546Z",
"iopub.status.busy": "2024-04-26T12:01:14.451546Z",
"iopub.status.idle": "2024-04-26T12:01:14.467233Z",
"shell.execute_reply": "2024-04-26T12:01:14.467233Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
" \n",
" \n",
" "
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"LetsPlot.setup_html()"
]
},
{
"cell_type": "markdown",
"id": "5067a158",
"metadata": {},
"source": [
"#### 1. Default Presentation"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "206a0bb9",
"metadata": {
"execution": {
"iopub.execute_input": "2024-04-26T12:01:14.467233Z",
"iopub.status.busy": "2024-04-26T12:01:14.467233Z",
"iopub.status.idle": "2024-04-26T12:01:15.904597Z",
"shell.execute_reply": "2024-04-26T12:01:15.904597Z"
}
},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 3,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"world = geocode_countries().inc_res().get_boundaries()\n",
"\n",
"ggplot() + geom_map(map=world)"
]
},
{
"cell_type": "markdown",
"id": "b8877904",
"metadata": {},
"source": [
"#### 2. Project \"World\" to the Robinson's"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "a2197755",
"metadata": {
"execution": {
"iopub.execute_input": "2024-04-26T12:01:15.908984Z",
"iopub.status.busy": "2024-04-26T12:01:15.908984Z",
"iopub.status.idle": "2024-04-26T12:01:16.486678Z",
"shell.execute_reply": "2024-04-26T12:01:16.486678Z"
}
},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 4,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"from cartopy import crs as ccrs\n",
"\n",
"# Define the CartoPy CRS object.\n",
"crs = ccrs.Robinson()\n",
"\n",
"# This can be converted into a `proj4` string/dict compatible with GeoPandas\n",
"crs_proj4 = crs.proj4_init\n",
"world_robinson = world.to_crs(crs_proj4)\n",
"\n",
"ggplot() + geom_map(map=world_robinson, use_crs=\"provided\")"
]
},
{
"cell_type": "markdown",
"id": "8e816608",
"metadata": {},
"source": [
"#### 3. Options"
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "7166ba40",
"metadata": {
"execution": {
"iopub.execute_input": "2024-04-26T12:01:16.487756Z",
"iopub.status.busy": "2024-04-26T12:01:16.487756Z",
"iopub.status.idle": "2024-04-26T12:01:16.992607Z",
"shell.execute_reply": "2024-04-26T12:01:16.991726Z"
}
},
"outputs": [
{
"data": {
"text/html": [
" \n",
" "
],
"text/plain": [
""
]
},
"execution_count": 5,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"(ggplot() + \n",
" geom_polygon(map=world_robinson, use_crs=\"provided\", color=\"white\") + \n",
" theme_void() + theme(plot_title=element_text(face=\"bold-italic\")) + flavor_solarized_light() + \n",
" ggsize(2048, 1096) + \n",
" xlim(-13E6, None) + \n",
" ggtitle(\"World in the Robinson Projection\")\n",
")"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3 (ipykernel)",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.10.13"
}
},
"nbformat": 4,
"nbformat_minor": 5
}