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Explore all that you can do with the latest ‘Spatial Join’

By Olly Normanton, QA Specialist


This is one feature we have all been waiting for. Spatial Join is a very useful tool to be included in the MAPublisher roster as of version 10.6 and I would like to share a little bit about the tool with you in this feature blog. 

The Spatial Join tool inserts the columns and attributes from one feature table to another based on location or proximity. Currently, we support several Spatial Join types including:

  • Intersects: If any part of two features touch at any location
  • Identical To: Both features match identically
  • Contains: When one feature intersects with the interior or boundary of another
  • Near: If a line can be drawn from any part of A to any part of B that is less than the specified minimum distance
  • Closest: If a line can be drawn from any part of A to any part of B that is less than any other such line between B & any other feature
  • Has Centre In: When one features centroid lies Within another feature
  • Within: If all of one feature lies within the interior boundary of another

 

Here is a wonderful map of Italy created by Hans van der Maarel of Red Geographics available through the One Stop Map service. It will provide a great way to show you some examples of the Spatial Join tool in action. It contains a Cities layer and a Regions layer and I would like to see which cities fall into each region by using Spatial Join.

Cities and Region Layer using MAPublisher 10.6

You can see below that the Cities attribute table contains the name of each city and there are 70 in total. 

MAP Attributes on MAPublisher 10.6

There are 20 different regions that these cities lie within. To figure out which cities belong to which region, we have the ability to spatially join attribute information from the Cities point layer to the Regions area layer. In addition, we’ll use the Concatenate operation on the NAME attribute to list all the cities that belong to a region in one field.

To do this, click the new Spatial Join button on the MAPublisher toolbar or access the Spatial Join dialog box via Object > MAPublisher > Spatial Join. 

Spatial Join Button on MAPublisher 10.6

The Spatial Join tool will always open on the Join tab seen below. I will be adding data to my Regions area layer and joining data from my Cities point layer. The relationship is set to Contains—in other words, when one feature intersects with the interior or boundary of another. A description of the operation is always provided beneath the relationship. 

Spatial Join Tool on MAPublisher 10.6

The Precision slider alters the tolerance that is used to determine when two values are equivalent (or approaching equivalent). Depending on your data, this may need to be altered in some cases but for this example, I will be leaving it in the default position. 

On the Attributes tab, I am going to concatenate the NAME field. By double-clicking on the attribute, I can access the Edit Calculated Attribute Operation dialog box. In addition, I am going to sum both the POP_MAX and POP_MIN attributes. I’m also going to append a Count attribute to the table so I can quickly verify how many cities are in each region.

Spatial Join Tool on MAPublisher 10.6

Within the Edit Calculated Attribute Operation dialog box, I am going to set the Operation drop-down to Concatenate and leave the separator as default as Comma then space. 

Spatial Join Tool on MAPublisher 10.6

After confirming the Spatial Join with the OK button, we’ll open the MAP Attribute table for the Regions area layer and take a look at the results.

Spatial Join Result

You can see that the cities have been concatenated by region and the POP_MAX and POP_MIN attributes have been summed for the regions based on the cities contained within them. The count attribute was also added to the attribute table and as only 56 of our 70 cities were within the Italian Regions area layer, that is the total value of our count. 

For the eagle-eyed readers who may have noticed that there are only 12 cities that surround Italy in the full map displayed at the beginning of this article and 70 – 56 = 14, the difference can be explained by San Marino and Vatican City, both of which are autonomous countries and not part of Italy. You can see that they are in fact separate polygons. 

City Map

For a full list of the relationships that are available based on the different layer types, and also the input attribute types, please see the tables below. 

Layer Attributes
Input Attribute Table

This post was made using the incredibly beautiful map data provided by our good friends over at One Stop Map. Stay tuned as MAPublisher Aware Maps are coming very soon to the One Stop Map Store, which will allow you to directly purchase the Adobe Illustrator files and put your own style on the maps! If you’re interested in seeing more of their work, take a look at these One Stop Map Country Maps.

 

Plotting Curved Lines in MAPublisher: It’s Here!

MAPublisher 10.6 has now been released and we are very excited to share these powerful new features with you. If you’re new to MAPublisher, you can get a rundown of the full feature set here, and even try it free for 14 days. In this feature highlight blog, I will be providing a brief overview of the ability to Plot Curved Lines with the Line Plotter tool. 

When plotting a line from point to point, you now have the option of selecting whether that line is Geodesic (also known as a Great Circle), Cartesian (planar), or a Rhumb Line (also known as Loxodromic). To provide a brief definition of each type:

Geodesic line: the shortest line between two points on a mathematically defined surface (as a straight line on a plane or an arc of a great circle on a sphere or ellipsoid like the Earth’s surface). On a geodesic line, the bearing to the destination point does not remain constant. This would be the type of line you would want to use when determining a flight path between two cities, for example. 

Rhumb line: this is a path with constant bearing as measured relative to true or magnetic north and is rarely the shortest line between two points. A rhumb line on a Mercator projection is a straight line which made the projection incredibly useful to navigators from as early as the 16th century.

 

Rhum Line Mercator - MAPublisher 10.6

Rhumb Lines on a Mercator Projection

Cartesian line: can simply be defined as a straight line connecting points.

To view this feature in action, we are going to be using curved geodesic lines to create an Airline Route Map. The reason why we are using geodesic lines for this type of map is because they provide the most economical route in terms of distance. Following the rhumb line would waste time and fuel for all but the most brief routes. 

I began by importing some data that provided my backdrop for the routes I am planning to map. My flights will span the entire globe so I required world coverage. You can also test out this feature and use the World.mif file or the WorldEast.shp and WorldWest.shp files provided in the MAPublisher tutorial data. 

I decided to use the Equal Earth Projected coordinate system.

Adding Locations

The next step was to establish the hubs from which our aircraft would fly and the destinations that we would offer as an airline company. For this, I needed points and coordinates. Instead of searching for and importing a hefty list of airports and then trying to filter down to ones of interest to me with selections, I opted to use the MAP Locations tool. 

MAP locations - MAPublisher 10.6

By utilizing the “Add Map Locations from web” feature highlighted at the bottom of the MAP Locations panel, adding each destination and its corresponding coordinates was as easy as typing in the city’s name. It can take a while to establish all of your locations but the best thing is that you only need to do this process once as the MAP Locations can easily be brought to other documents using the Copy MAP Objects From feature.

Copy MAP Objects - MAPublisher 10.6

Plotting Points

Now that I had all of my locations of interest and their coordinates, I could plot these onto my map as points. For this I used the MAP Point Plotter. 

Plotting Points - MAPublisher 10.6

By accessing the panel options menu in the top right-hand corner, you can select Plot MAP Locations. In the dialog that opens, select all of the city MAP Locations. In my example, I selected all and then de-selected Abu Dhabi and Toronto as these will be my main hubs and will be plotted with a different custom symbol to other destinations.

Plot MAP Locations - MAPublisher 10.6

I chose to plot them to a new Point layer that I named “Cities” and I included WGS84 values as attributes. I created a custom red main hub symbol using Adobe Illustrator tools to use for my destinations. You may need to play with the scaling of the symbol to get your desired look. 

Location Symbol on Avenza Maps

To create a custom symbol in Adobe Illustrator, draw out your design like the main hub symbol above, highlight the art, and drag the art to the Symbol window that can be accessed by going to Window > Symbols. You can then give it a name and select the static symbol option. 

Plotting the Routes

With the cities and main hubs now plotted, it was time to add the routes. 

plotting the routes - MAPublisher 10.6

Line Plotter - MAPublisher 10.6

I targeted a new Line layer called “Routes” and set my start point using the MAP Locations selector. I was sure to change the Method to Geodesic. 

Line Plotter - MAPublisher 10.6
I started adding cities using the “Add Point from MAP Location” control shown here. Once you select your point, a preview will be drawn onto the artboard if your “Show line preview” option is checked.

Line Plotter - MAPublisher 10.6

The route above is from Abu Dhabi to Mexico City. You can select multiple destinations to account for layovers. You can also change the order of the points once they are in the list using the arrows highlighted below. 

Line Plotter - MAPublisher 10.6

Once all of the routes have been plotted, the points were labelled with MAP Label Pro and a customized graticule was added. Here’s the final map in two projection styles to show how a map projection can change the look of the routes and the overall look of the map.

Airline Route Map - Avenza Systems

Projected Coordinate System: Equal Earth

Geodetic Route Map - Avenza Systems

Geodetic Coordinate System: WGS84

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By Olly Normanton, QA Specialist