Estrarre numero pagine da un PDF

Introduzione

Un utente di QGIS mi contatta e mi chiede come estrarre il numero di pagine di un PDF usando le espressioni di QGIS.

!!! Abstract "Funzione personalizzata" QGIS ha centinaia di espressioni, per quelle che mancano o per crearne di nuove è possibile aggiungere delle funzioni personalizzate usando PyQGIS

Who are we?

For those unfamiliar with Oslandia, OpenGIS.ch, or even QGIS, let’s refresh your memory:

Oslandia is a French company specializing in open-source Geographic Information Systems (GIS). Since our establishment in 2009, we have been providing consulting, development, and training services in GIS, with reknown expertise. Oslandia is a dedicated open-source player and the largest contributor to the QGIS solution in France.

As for OPENGIS.ch, they are a Swiss company specializing in the development of open-source GIS software. Founded in 2011, OPENGIS.ch is the largest Swiss contributor to QGIS. OPENGIS.ch is the creator of QField, the most widely used open-source mobile GIS solution for geomatics professionals.

OPENGIS.ch also offers QFieldCloud as a SaaS or on-premise solution for collaborative field project management.

Some may still be unfamiliar with #QGIS ?

It is a free and open-source Geographic Information System that allows creating, editing, visualizing, analyzing, and publicating geospatial data. QGIS is a cross-platform software that can be used on desktops, servers, as a web application, or as a development library.

QGIS is open-source software developed by multiple contributors worldwide. It is an official project of the OpenSource Geospatial Foundation (OSGeo) and is supported by the QGIS.org association. See https://qgis.org

A Partnership?

Today, we are delighted to announce our strategic partnership aimed at strengthening and promoting QField, the mobile application companion of QGIS Desktop.

This partnership between Oslandia and OPENGIS.ch is a significant step for QField and open-source mobile GIS solutions. It will consolidate the platform, providing users worldwide with simplified access to effective tools for collecting, managing, and analyzing geospatial data in the field.

QField, developed by OPENGIS.ch, is an advanced open-source mobile application that enables GIS professionals to work efficiently in the field, using interactive maps, collecting real-time data, and managing complex geospatial projects on Android, iOS, or Windows mobile devices.

QField is cross-platform, based on the QGIS engine, facilitating seamless project sharing between desktop, mobile, and web applications.

QFieldCloud (https://qfield.cloud), the collaborative web platform for QField project management, will also benefit from this partnership and will be enhanced to complement the range of tools within the QGIS platform.

Reactions

At Oslandia, we are thrilled to collaborate with OPENGIS.ch on QGIS technologies. Oslandia shares with OPENGIS.ch a common vision of open-source software development: a strong involvement in development communities, work in respect with the ecosystem, an highly skilled expertise, and a commitment to industrial-quality, robust, and sustainable software development.

With this partnership, we aim to offer our clients the highest expertise across all software components of the QGIS platform, from data capture to dissemination.

On the OpenGIS.ch side, Marco Bernasocchi adds:

The partnership with Oslandia represents a crucial step in our mission to provide leading mobile GIS tools with a genuine OpenSource credo. The complementarity of our skills will accelerate the development of QField and QFieldCloud and meet the growing needs of our users.

Commitment to open source

Both companies are committed to continue supporting and improving QField and QFieldCloud as open-source projects, ensuring universal access to this high-quality mobile GIS solution without vendor dependencies.

Ready for field mapping ?

And now, are you ready for the field?

So, download QField (https://qfield.org/get), create projects in QGIS, and share them on QFieldCloud!

If you need training, support, maintenance, deployment, or specific feature development on these platforms, don’t hesitate to contact us. You will have access to the best experts available: [email protected].

Array nel field calc

Introduzione

Il gruppo Array è stato introdotto in QGIS nella prima versione di QGIS 3.0 Girona nel lontano 2018, nella descrizione leggiamo:

!!! Abstract "GRUPPO ARRAY" Nuovo gruppo che contiene funzioni di espressione per la creazione e la manipolazione di array (noti anche come strutture di dati di elenco). L'ordine dei valori all'interno dell'array è importante, contrariamente alla struttura dei dati "mappa", dove l'ordine delle coppie chiave-valore è irrilevante e i valori sono identificati dalle rispettive chiavi.

Impostazioni di progetto influenzano alcune funzioni

Introduzione

Alcune funzioni di QGIS dipendono dalle impostazioni di progetto, questo significa che le stesse funzioni in progetti diversi possono restituire valori diversi. In questo post vedremo le principali funzioni di QGIS da attenzionare.

!!! Abstract "esempio" $area <> area(@geometry)

Come cercare un valore in funzione di un altro

Introduzione

Alcune volte nasce l'esigenza di cercare un valore in una tabella in funzione di un altro valore presente nella stessa tabella, un po' come fa la funzione cerca verticale di Excel, e utilizzarlo in un altro layer.

!!! Abstract "Funzione" La funzione che permette di fare questa magia è la funzione get_feature

HfcQGIS e la sezione Blog

Introduzione

Benvenuti nel nuovo blog di HfcQGIS!

HfcQGIS è la guida al calcolatore di campi di QGIS per la condivisione di conoscenze ed ora ha il suo Blog!!!.

HfcQGIS è un sito web nato nel 2018 da un'idea di Totò Fiandaca e realizzato con la comunità OpenDataSicilia, un particolare grazie va a Giovan Battista Vitrano che mantiene sempre aggiornato il tema del sito alle ultime novità. L'obiettivo iniziale del sito era quello di fornire una guida completa al calcolatore di campi, un potente strumento che consente di eseguire calcoli sui dati geografici.

Negli anni, HfcQGIS si è evoluto in una piattaforma di condivisione di contenuti per la comunità QGIS. Il sito offre ora una serie di risorse, tra cui:

Growing up, I would spend hours lost in National Geographic maps. The feeling of discovering new regions and new ways to view the world was addictive! It’s this same feeling of discovery and exploration which has made me super excited about Soar’s Digital Atlas. Soar is the brainchild of Australian, Amir Farhand, and is fuelled by the talents of staff located across the globe to build a comprehensive digital atlas of the world’s maps and images. Soar has been designed to be an easy to use, expansive collection of diverse maps from all over the Earth. A great aspect of Soar is that it has implemented Strong Community Guidelines and moderation to ensure the maps are fit for purpose.

Recently, North Road collaborated with Soar to help facilitate their digital atlas goals by creating a QGIS plugin for Soar. The Soar plugin allows QGIS users to directly:

• Export their QGIS maps and images straight to Soar
• Browse and load maps from the entire Soar public catalogue into their QGIS projects

There’s lots of extra tweaks we’ve added to help make the plugin user friendly, whilst offering tons of functionality that power users want. For instance, users can:

• Filter Soar maps by their current project extent and/or by category
• Export raw or rendered raster data directly to Soar via a Processing tool
• Batch upload multiple maps to Soar
• Incorporate Soar map publishing into a Processing model or Python based workflow

Soar will be presenting their new plugin at the QGIS Open Day in August so check out the details here and tune in at 2300 AEST or 1300 HR UTC. You can follow along via either YouTube or Jitsi.

Browsing Soar maps from QGIS

One of the main goals of the Soar QGIS plugin was to make it very easy to find new datasets and add them to your QGIS projects. There’s two ways users can explore the Soar catalog from QGIS:

You can open the Soar Browser Panel via the Soar toolbar button  . This opens a floating catalog browser panel which allows you to interactively search Soar’s content while working on your map.

Alternatively, you can also access the Soar catalog and maps from the standard QGIS Data Source Manager dialog. Just open the “Soar” tab and search away!

When you’ve found an interesting map, hit the “Add to Map” button and the map will be added as a new layer into your current project. After the layer is loaded you can freely modify the layer’s style (such as the opacity, colorization, contrast etc) just like any other raster dataset using the standard QGIS Layer Style controls.

Sharing your maps

Before you can share your maps on Soar, you’ll need to first sign up for a free Soar account.

We’ve designed the Soar plugin with two specific use cases in mind for sharing maps. The first use case is when you want to share an entire map (i.e. QGIS project) to Soar. This will publish all the visible content from your map onto Soar, including all the custom styling, labeling, decorations and other content you’ve carefully designed. To do this, just select the Project menu, Import/Export -> Export map to Soar option.

You’ll have a chance to enter all the metadata and descriptive text explaining your map, and then the map will be rendered and uploaded directly to Soar.

All content on the Soar atlas is moderated, so your shared maps get added to the moderation queue ready for review by the Soar team. (You’ll be notified as soon as the review is complete and your map is publicly available).

Alternatively, you might have a specific raster layer which you want to publish on Soar. For instance, you’ve completed some flood modelling or vegetation analysis and want to share the outcome widely. To do this, you can use the “Publish dataset to Soar” tool available from the QGIS Processing toolbox:

Just pick the raster layer you want to upload, enter the metadata information, and let the plugin do the rest! Since this tool is made available through QGIS’ Processing framework, it also allows you to run it as a batch process (eg uploading a whole folder of raster data to Soar), or as a step in your QGIS Graphical Models!

Some helpful hints

All maps uploaded to Soar require the following information:

• Map Title
• Description
• Tags
• Categories
• Permission to publish

This helps other users to find your maps with ease, and also gives the Soar moderation team the information required for their review process.

We’ve a few other tips to keep in mind to successfully share your maps on Soar:

• The Soar catalog currently works with raster image formats including GeoTIFF / ECW / JP2 / JPEG / PNG
• All data uploaded to Soar must be in the WGS84 Pseudo-Mercator (EPSG: 3857) projection
• Check the size of your data before sharing it, as a large size dataset may take a long time to upload

So there you have it! So simple to start building up your contribution to Soar’s Digital Atlas. Those who might find this useful to upload maps include:

• Community groups
• Hobbyists
• Building a cartographic/geospatial portfolio
• Education/research
• Contributing to world events (some of the biggest news agencies already use this service i.e. BBC)

You can find out more about the QGIS Soar plugin at the QGIS Open Day on August 23rd, 2023 at 2300 HR AEST or 1300 HR UTC. Check here for more information or to watch back after.

If you’re interested in exploring how a QGIS plugin can make your service easily accessible to the millions of daily QGIS users, contact us to discuss how we can help!

Years ago, the QField community and its users showed their love for their favourite field app by supporting a successful crowdfunding to improve camera handling.

Since then, OPENGIS.ch has continued to lead the development of QField with the regular support of sponsors. We couldn’t be prouder of the progress we have made, with plenty of new features added in every major release. This includes major improvements to positioning including location tracking, integration of external GNSS receivers through not only Bluetooth but TCP/UDP and serial port connections, accuracy indicator and constraints, and most recently sensors reading to list a few.

We are now calling for the community to help further better QField and unlock an important milestone: background location tracking service.

Pledge now

Main goal: background location tracking on Android – 25'000€

Currently, QField requires users to keep their devices’ screen on and have the app in the foreground to keep track of the device’s positioning location. On mobile devices, this can drain batteries faster than many would want to, in environments where charging options are limited.

This crowdfunding aims at removing this constraint and allow QField - via a background service - to constantly keep tracking location even while the device is suspended (i.e., when the screen is turned off / locked).

To achieve this, a significant amount of work is required as the positioning framework on Android will need to be relocated to a dedicated background service. Recent work we’ve done adding a background service to synchronize captured image attachments in QFieldCloud projects armed us with the assurances that we can achieve our goal while giving us an appreciation of the large amount of work needed.

Some of the benefits

Running out of battery is the nightmare of most field surveyors. By moving location tracking to a background service, users will be able to improve their battery life considerably and keep focusing on their tasks even if it involves switching to a different app.

Furthermore, while OPENGIS.ch ninjas remain busy squashing reported QField crashes all year long, there will always be unexpected scenarios leading to abrupt app shutdowns, such as third-party apps, systems running out of battery, etc. To address this, the background service framework will also act as a safeguard to avoid location data loss when QField unexpectedly shuts down and offer users means to recover that data upon re-opening QField.

Stretch goal 1: background navigation audio feedback 5'000€

The second stretch goal builds onto QField’s nice fly-to-point navigation system. If the QField community meets this threshold, a new background navigation audio feedback informing users in the field of their proximity to their target will be implemented.

The audio feedback will use text-to-speech technology to state the distance to target in meters for a given time or distance interval.

Stretch goal 2: iOS 15'000€

The main goal will cover the Android implementation only. Due to being a very low level work we will have to replicate the work for each platform we support. If we reach stretch goal 2 we will also implement this for iOS.

Pledge now:

In case you do not see the embedded form you can open it directly here.

Thanks for supporting our crowdfunding and keep an eye on our blog for updates on the status.

The gift economy of Open Source is community driven and filled by folks with ideas that just go for it!

We at North Road are blessed that we get to join these creatives on their journey in order to get their products to you. Recently, the first QGIS flagship sponsor, Felt, engaged us to further strengthen their support for the up to 600,000 daily QGIS users to integrate their workflows between QGIS and Felt.

The result is the “Add to Felt” QGIS Plugin, which makes it super-simple to publish your QGIS maps to the Felt platform.

To get started, install the Add to Felt Plugin from the QGIS Plugin manager.

If you don’t have a free Felt account, you’ll need to sign up for one online (or from the Add to Felt plugin itself once you have installed it).

Within QGIS, users can easily publish their maps and layers to Felt. You can either:

• Publish a single layer by right-clicking the layer and selecting “Share Layer to Felt” from the Export sub-menu
• Publish your whole QGIS project/map by selecting the Project Menu, Export, “Add to Felt” action

Whilst Felt is loading up your map, you can continue working and it will let you know once your map is ready to open on Felt and share with others.

We are happy to let you know that the collaboration does not stop there! As with our SLYR tool, there is ongoing development as the requirements of the community and technology grow.  So install the Add to Felt Plugin via the QGIS Plugin manager, and let us know where you want it to go via the Add to Felt GitHub page.

Read more about it here:

• Felt’s Blog about the QGIS Plugin
• Installation Guide
• Getting Started for QGIS Users