trents_blog/docs/posts/open-elevation-api-server-upgrade.md

---
title: "Open Elevation Api Server Upgrade"
date: 2025-02-02
draft: false
tags: ["linux", "Debian", "bookworm", "buster", "bullseye", "bottle", "geospatial"]
authors: ["trent"]
post: 36
---
date: 2025-02-02

## Introduction
A while back I left an open-elevation-api-server running on Debian 10, and I can't remember why.

But I have now worked out how to get it running on Debian 10, Debian 11, and Debian 12
so I want to have what I learned written down here.
### What is This?
The api returns an elevation when you query it with gps coordinates.

i.e. you want the elevation at Boring Bowling Alley and Petting Zoo?
```bash
curl 'https://elevation.boringonian.com/api/v1/lookup?locations=45.42949,-122.37563'
```

```json
{"results": [{"latitude": 45.42949, "longitude": -122.37563, "elevation": 157}]}
```

## What changed?
Going from Debian 10 to Debian 11, you have to change how to import gdal and osr.
```python
# gdal_interfaces.py
# import gdal, osr
from osgeo import gdal, osr
...
```
Going from Debian 11 to Debian 12, `python3-lazy` is now installable from `apt-get`;
no more _cowboy-pip3-installs_ ; all dependencies are now available from `apt-get`.

## Debian 10 Installation 
### install dependencies
Here's how I got this working on Debian 10.
```bash
apt install python3-bottle python3-gunicorn
apt install gdal-bin python3-gdal
apt install python3-rtree python3-pip
pip3-install lazy
```
### create user and home directory
```bash
mkdir /var/lib/elevation
useradd -r -s /sbin/nologin -d /var/lib/elevation elevation
```

### setup your data directory
[Follow the instructions](https://github.com/Jorl17/open-elevation/blob/master/docs/host-your-own.md)
for extracting your 400 `*.tif` files and 1 `summary.json`
to `/var/lib/elevation/data/`.

Also place `gdal_interfaces.py` and `server.py` in
`/var/lib/elevation/`

in `server.py` I comment out the config-parser stuff and just hardcode
the following
```python
# server.py
interface = GDALTileInterface('data/', 'data/summary.json')                                                                                                                                                        
interface.create_summary_json()
```

And of course then at the very bottom of `server.py` adjust the
_run_ command for the host and port that you want gunicorn to listen on.

## Debian 11 Installation 
In upgrading from Debian 10 to Debian 11, change how you import gdal and osr.
```python
# gdal_interfaces.py
# import gdal, osr
from osgeo import gdal, osr
...
```
Additionally, and I'm not completely clear if this is necessary or not, I deleted
`/usr/local/lib/python3.7/` and then once again installed `lazy`.
```bash
rm -rf /usr/local/lib/python3.7/

# installs lazy in /usr/local/lib/python3.9/
pip3-install lazy
```

## Debian 12 Installation
In upgrading from Debian 11 to Debian 12, it is no longer necessary to install lazy
with pip.

```bash
rm -rf /usr/local/lib/python3.9/
apt install python3-lazy
```

## Run as Systemd Service
This is probably just based on a google search how to run a `bottle`
server with `gunicorn` from `systemd`.
```conf
# /etc/systemd/system/elevation.service
[Unit]
Description=Bottled Elevation API 
After=network.target remote-fs.target nss-lookup.target

[Service]
Type=simple
User=elevation
Group=elevation
WorkingDirectory=/var/lib/elevation
ExecStart=/usr/bin/python3 /var/lib/elevation/server.py
StandardOutput=inherit
StandardError=inherit
Restart=always
RestartSec=2

[Install]
WantedBy=multi-user.target
```