Tag: cartography

QGIS Add to Felt Plugin – Phase 2

We have been continuing our work with the Flagship sponsor of QGISFelt to develop their QGIS Plugin – Add to Felt  that makes it even easier to share your maps and data on the web.

What is the ‘Add to Felt’ QGIS Plugin?

The ‘Add to Felt’ QGIS Plugin is a powerful tool that empowers users to export their QGIS projects and layers directly to a Felt web map. This update introduces two fantastic features:

  1. Single Layer Sharing: You can now share a single layer from your QGIS project to a Felt map. This means you have greater control over which specific data layers to share, allowing you to tailor your map precisely to your audience’s needs.
  2. Map Selection: With the updated plugin, you can choose which map on Felt to add your layer to – a new map, or an ongoing project. This flexibility simplifies your workflow and ensures that your data ends up in the right place.

Businesses that rely on QGIS love how these new features provide a seamless way to view and share results, ultimately allowing them to move more quickly and stay in sync:

“Felt helps us keep each other updated on what we’ve done, what we’ve modeled, how things are progressing.” – ICON Engineering

Why is this Update Important?

Web maps are invaluable tools for sharing data with a wider audience, be it colleagues, clients, or the public. They provide creators with the ability to control data visibility, display options, and audience access, all within an easily shareable digital format. However, creating web maps can be an arduous and complex task.

Here’s where the ‘Add to Felt’ QGIS Plugin update comes to the rescue:

1. Streamlining the Process: Creating web maps traditionally involves website development, data hosting, and map application development—tasks that require a diverse skill set. This complexity can be a significant barrier, especially for smaller operations with limited resources or budget constraints.

2. Felt Simplifies Web Mapping: Felt makes it effortless to create web maps, and share them as easily as you would a Google Doc or Sheet. Simply drag and drop your data, customize the symbology to your liking, and share the map with a link or by inviting collaborators. No need to send large data files or answer questions about the map’s data sources.

3. Integration with QGIS: Now, the ‘Add to Felt’ QGIS Plugin bridges the gap between QGIS and Felt. It seamlessly imports your QGIS data into Felt, eliminating the need for manual data transfers and reducing the complexity of web map creation.

In essence, the ‘Add to Felt’ QGIS Plugin update simplifies the process of sharing and collaborating on web maps. It empowers users to harness the full potential of web-based mapping, making it accessible to everyone, regardless of their technical expertise. The update makes it even easier to share progress updates or model re-run outputs without creating a new map, or sharing a new map link.

So, if you’re a QGIS user looking to enhance your map-sharing capabilities and streamline your workflow, make sure to take advantage of this fantastic update. Say goodbye to the complexities of web map creation and hello to effortless, data-rich web maps with Felt and the ‘Add to Felt’ QGIS Plugin.

How to install and upgrade

  • Open QGIS on your computer. You must have version 3.22 or later installed.
  • In the plugins tab, select Manage and Install Plugins.
  • Search for the ‘Add to Felt’ plugin, select and click Install Plugin.
  • Close the Plugins dialog. The Felt plugin toolbar will appear in your toolbar for use.
  • Sign into Felt and begin sharing your maps to the web.

If you want more features in this plugin, let us know or 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!

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Soar.Earth Digital Atlas QGIS Plugin

Soar banner

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  Soar browser . This opens a floating catalog browser panel which allows you to interactively search Soar’s content while working on your map.

Soar browser panel

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.

Upload via Project to Soar

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.

Soar Metadata

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:

Upload product to Soar via processing tools

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!

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Creating circular insets and other fun QGIS layout tricks

Thanks to the recent popularity of the “30 Day Map Challenge“, the month of November has become synonymous with beautiful maps and cartography. During this November we’ll be sharing a bunch of tips and tricks which utilise some advanced QGIS functionality to help create beautiful maps.

One technique which can dramatically improve the appearance of maps is to swap out rectangular inset maps for more organic shapes, such as circles or ovals.

Back in 2020, we had the opportunity to add support for directly creating circular insets in QGIS Print Layouts (thanks to sponsorship from the City of Canning, Australia!). While this functionality makes it easy to create non-rectangular inset maps the steps, many QGIS users may not be aware that this is possible, so we wanted to highlight this functionality for our first 30 Day Map Challenge post.

Let’s kick things off with an example map. We’ve shown below an extract from the 2032 Brisbane Olympic Bid that some of the North Road team helped create (on behalf of SMEC for EKS). This map is designed to highlight potential venues around South East Queensland and the travel options between these regions:

Venue Masterplan Brisbane 2032 Olympics
Venue Masterplan for 2032 Olympic Games, IOC Feasibility Assessment – Olympic Games, Brisbane February 2021

Circles featured heavily in previous Olympic bid maps (such as Budapest) where we took our inspiration from. This may, or may not, play a part in using the language of the target map audience – think Olympic rings!

Budapest Olympics 2024 MasterplanBudapest Olympics 2024 Masterplan

 

Step by Step Guide to Creating a Circle Inset

Firstly, prepare a print layout with both a main map and an inset map. Make sure that your inset map is large enough to cover your circular shape:

From the Print Layout toolbar, click on the Add Shape button and then select Add Ellipse:

Draw the ellipse over the middle of your inset map (hint: holding down Shift while drawing the ellipse will force it to a circular shape!). If you didn’t manage to create an exact circle then you can manually specify the width and height in the shape item’s properties. For this one, we went with a 50mm x 50mm circle:

Next, select the Inset Map item and in its Item Properties click on the Clipping Settings button:

In the Clipping Settings, scroll down to the second section and tick the Clip to Item box and select your Ellipse item from the list. (If you have labels shown in your inset map you may also want to check the “force labels inside clipping shape” option to force these labels inside the circle. If you don’t check this option then labels will be allowed to overflow outside of the circle shape.)

Your inset map will now be bound to the ellipse!

Here’s a bit more magic you could add to this map – in the Main Map’s properties, click on Overviews and set create one for the Inset map – it will nicely show the visible circular area and not the rectangle!

Bonus Points: Circular Title Text!

For advanced users, we’ve another fun tip…and when we say fun, we mean ‘let’s play with radians’! Here we’re going to create some title text and a wedged background which curves around the outside of our circular inset. This takes some fiddly playing around, but the end result can be visually striking! Here we’re going to push the QGIS print layout “HTML” item to create some advanced graphics, so some HTML and CSS coding experience is advantageous. (An alternative approach would be to use a vector illustration application like Inkscape, and add your title and circular background as an SVG item in the print layout).

We’ll start by creating some curved circular text:

First, add a “HTML frame” to your print layout:

HTML frames allow placement of dynamic content in your layouts, which can use HTML, CSS and JavaScript to create graphical components.

In the HTML item’s “source” box, add the following code:

<svg height="300" width="350">
        <defs>
            <clipPath id="circleView">
                <circle id="curve" cx="183" cy="156" r="25" fill="transparent" />
            </clipPath>
        </defs>
        <path id="forText" d="M 28,150, C 25,50, 180,-32,290,130" stroke="" fill="none"/>
            <text x="0" y="35" width="100">
                <textpath xlink:href="#forText">
                    <tspan font-weight="bold" fill="black">Place text here</tspan>
                </textpath>
            </text>
             <style>
    <![CDATA[
      text{
        dominant-baseline: hanging;
        font: 20px Arial;
      }
    ]]>
  </style>
</svg>

Now, let’s add in a background to bring more focus onto the title!

To add in the background, create another HTML item. We’ll again create the arc shape using an SVG element, so add the following code into the item’s source box:

<svg width="750" height="750" xmlns="http://www.w3.org/2000/svg">
  <path d="M 90 70
           A 56 56, 0, 0, 0, 133 140
           L 150 90 Z" fill="#414042" transform=" scale(2.1) rotate(68 150 150) " />/>
</svg>

(You can read more about SVG  curves and arcs paths over at MDN)

So there we go! These two techniques can help push your QGIS map creations further and make it easier to create beautiful cartography directly in QGIS itself. If you found these tips useful, keep an eye on this blog as we post more tips and tricks over the month of November. And don’t forget to follow the 30 day Map Challenge for a smorgasbord of absolutely stunning maps.

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About label halos

A lot of cartographers have a love/hate relationship with label halos. On one hand they can be an essential technique for improving label readability, especially against complex background layers. On the other hand they tend to dominate maps and draw unwanted attention to the map labels.

In this post I’m going to share my preferred techniques for using label halos. I personally find this technique is a good approach which minimises the negative effects of halos, while still providing a good boost to label readability. (I’m also going to share some related QGIS 3.0 news at the end of this post!)

Let’s start with some simple white labels over an aerial image:

These labels aren’t very effective. The complex background makes them hard to read, especially the “Winton Shire” label at the bottom of the image. A quick and nasty way to improve readability is to add a black halo around the labels:

Sure, it’s easy to read the labels now, but they stand out way too much and it’s difficult to see anything here except the labels!

We can improve this somewhat through a better choice of halo colour:

This is much better. We’ve got readable labels which aren’t too domineering. Unfortunately the halo effect is still very prominent, especially where the background image varies a lot. In this case it works well for the labels toward the middle of the map, but not so well for the labels at the top and bottom.

A good way to improve this is to take advantage of blending (or “composition”) modes (which QGIS has native support for). The white labels will be most readable when there’s a good contrast with the background map, i.e. when the background map is dark. That’s why we choose a halo colour which is darker than the text colour (or vice versa if you’ve got dark coloured labels). Unfortunately, by choosing the mid-toned brown colour to make the halos blend in more, we are actually lightening up parts of this background layer and both reducing the contrast with the label and also making the halo more visible. By using the “darken” blend mode, the brown halo will only be drawn for pixels were the brown is darker then the existing background. It will darken light areas of the image, but avoid lightening pixels which are already dark and providing good contrast. Here’s what this looks like:

The most noticeable differences are the labels shown above darker areas – the “Winton Shire” label at the bottom and the “Etheridge Shire” at the top. For both these labels the halo is almost imperceptible whilst still subtly doing it’s part to make the label readable. (If you had dark label text with a lighter halo color, you can use the “lighten” blend mode for the same result).

The only issue with this map is that the halo is still very obvious around “Shire” in “Richmond Shire” and “McKinlay” on the left of the map. This can be reduced by applying a light blur to the halo:

There’s almost no loss of readability by applying this blur, but it’s made those last prominent halos disappear into the map. At first glance you probably wouldn’t even notice that there’s any halos being used here. But if we compare back against the original map (which used no halos) we can see the huge difference in readability:

Compare especially the Winton Shire label at the bottom, and the Richmond Shire label in the middle. These are much clearer on our tweaked map versus the above image.

Now for the good news… when QGIS 3.0 is released you’ll no longer have to rely on an external illustration/editing application to get this effect with your maps. In fact, QGIS 3.0 is bringing native support for applying many types of live layer effects to label buffers and background shapes, including blur. This means it will be possible to reproduce this technique directly inside your GIS, no external editing or tweaking required!

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New map coloring algorithms in QGIS 3.0

It’s been a long time since I last blogged here. Let’s just blame that on the amount of changes going into QGIS 3.0 and move on…

One new feature which landed in QGIS 3.0 today is a processing algorithm for automatic coloring of a map in such a way that adjoining polygons are all assigned different color indexes. Astute readers may be aware that this was possible in earlier versions of QGIS through the use of either the (QGIS 1.x only!) Topocolor plugin, or the Coloring a map plugin (2.x).

What’s interesting about this new processing algorithm is that it introduces several refinements for cartographically optimising the coloring. The earlier plugins both operated by pure “graph” coloring techniques. What this means is that first a graph consisting of each set of adjoining features is generated. Then, based purely on this abstract graph, the coloring algorithms are applied to optimise the solution so that connected graph nodes are assigned different colors, whilst keeping the total number of colors required minimised.

The new QGIS algorithm works in a different way. Whilst the first step is still calculating the graph of adjoining features (now super-fast due to use of spatial indexes and prepared geometry intersection tests!), the colors for the graph are assigned while considering the spatial arrangement of all features. It’s gone from a purely abstract mathematical solution to a context-sensitive cartographic solution.

The “Topological coloring” processing algorithm

Let’s explore the differences. First up, the algorithm has an option for the “minimum distance between features”. It’s often the case that features aren’t really touching, but are instead just very close to each other. Even though they aren’t touching, we still don’t want these features to be assigned the same color. This option allows you to control the minimum distance which two features can be to each other before they can be assigned the same color.

The biggest change comes in the “balancing” techniques available in the new algorithm. By default, the algorithm now tries to assign colors in such a way that the total number of features assigned each color is equalised. This avoids having a color which is only assigned to a couple of features in a large dataset, resulting in an odd looking map coloration.

Balancing color assignment by count – notice how each class has a (almost!) equal count

Another available balancing technique is to balance the color assignment by total area. This technique assigns colors so that the total area of the features assigned to each color is balanced. This mode can be useful to help avoid large features resulting in one of the colors appearing more dominant on a colored map.

Balancing assignment by area – note how only one large feature is assigned the red color

The final technique, and my personal preference, is to balance colors by distance between colors. This mode will assign colors in order to maximize the distance between features of the same color. Maximising the distance helps to create a more uniform distribution of colors across a map, and avoids certain colors clustering in a particular area of the map. It’s my preference as it creates a really nice balanced map – at a glance the colors look “randomly” assigned with no discernible pattern to the arrangement.

Balancing colors by distance

As these examples show, considering the geographic arrangement of features while coloring allows us to optimise the assigned colors for cartographic output.

The other nice thing about having this feature implemented as a processing algorithm is that unlike standalone plugins, processing algorithms can be incorporated as just one step of a larger model (and also reused by other plugins!).

QGIS 3.0 has tons of great new features, speed boosts and stability bumps. This is just a tiny taste of the handy new features which will be available when 3.0 is released!

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Hack to adjust map symbols location in QGIS

EN | PT

Now and then I get too many map symbols (points) in the same place, and I thought how nice it would be if we could drag n’ drop them around without messing with their geometries position, just like we do with labels. That thought gave me an idea for a cool hack.

Choose your point layer and start by creating two new fields called symbX and symbY (Type: Decimal number; Size: 20; Precision: 5). Now go the layer properties and in the Style tab edit your symbol. For each level of your symbol select “map units” as the offset units, and set the following expression in the offset data define properties option:


CASE WHEN symbX IS NOT NULL AND symbY IS NOT NULL THEN
    tostring($x - symbX) + ',' + tostring($y - symbY)
ELSE
    '0,0'
END

Screenshot from 2015-02-22 18:18:43

Be aware that, if your coordinates have negative values, you need to adapt the code. E.g., If you have negative values in X you should use “tostring(symbX -$x)” instead.

Now, temporarly  label your layer with a small convenient text (I used a centered ‘+’ (plus sign) with a white buffer) and set its coordinates to data defined using the symbX and symbY Fields.

Screenshot from 2015-02-22 22:42:07

From this point on, when you use the move label tool, not only the label position change but also the actual symbol! Pretty cool, isn’t it?

anim

Notice that the features geometries are not changed during the process. Also, remember that in this case you can also add leading lines to connect the symbols to the original position of the points.

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Labels leading lines with QGIS and Postgis

EN | PT

Recently I had the need to add labels to features with very close geometries, resulting in their collision.

Capturar_3

Using data-defined override for label’s position (I have used layer to labeled layer plugin to set this really fast) and the QGIS tool to move labels, it was quite easy to relocate them to better places. However, in same cases, it was difficult to understand to which geometry they belonged.

Capturar_2

I needed some kind of leading lines to connect, whenever necessary, label and feature. I knew another great plugin called “Easy Custom Labeling“, by Regis Haubourg, that did what I needed, but it would create a memory duplicate of the original layer, wish meant that any edition on the original layer wouldn’t be updated in the labels.

Since the data were stored in a PostgreSQL/Postgis database, I have decided to create a query that would return a layer with leading lines. I used the following query in DB manager:

SELECT
  gid,
  label,
  ST_Makeline(St_setSRID(ST_PointOnSurface(geom),27493), St_setSRID(St_Point(x_label::numeric, y_label::numeric),27493))
FROM
  epvu.sgev
WHERE
  x_label IS NOT NULL AND
  y_label IS NOT NULL AND
  NOT ST_Within(ST_Makeline(St_setSRID(ST_PointOnSurface(geom),27493), St_setSRID(St_Point(x_label::numeric, y_label::numeric),27493)),geom))

This query creates a line by using the feature centroid as starting point and the label coordinate as end point. The last condition on the WHERE statement assures that the lines are only created for labels outside the feature.

Capturar_1

With the resulting layer loaded in my project, all I need is to move my labels and save the edition (and press refresh) to show a nice leading line.

guidelines

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