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Carto-Jargon 201: Cartography Terms Defined

In a previous blog post, we defined a few common cartography terms that you might be likely to encounter while using MAPublisher and Geographic Imager; however, that was just the tip of the iceberg when it comes to cartography and GIS jargon. Here, in no particular order, are several additional terms used by cartographers, GIS professionals and people who work with spatial imagery.

Topology

Topology is a key principle in GIS for data management and integrity, ensuring the data quality of spatial relationships is maintained. In general, a topological data model defines how spatial objects (point, line, and area features) are represented, and defines and enforces data integrity rules (for example, there should be no gaps between polygons).

Azimuth

The horizontal angle, measured in degrees, between a baseline drawn from a center point and another line drawn from the same point. Normally, the baseline points true north and the angle is measured clockwise from the baseline.

Neatline

All 2-dimensionally rendered maps have to compromise somewhat on accuracy, even if only just a little by moving or scaling features to improve readability. However, the neatline is never adjusted, making it the most accurate element on a map.

The neatline is the border defining the extent of geographic data on a map and separating the body of the map from the map margin. It demarcates map units such as meridians and parallels, and depending on the map projection and the units selected, the neatline may not have 90-degree corners.  

Geodatabase

A Geodatabase, a database or file structure used primarily to store, query, and manipulate spatial data, stores geometry, a spatial reference system, attributes, and behavioral rules for data. An advantage of geodatabases over shapefiles is that various types of geographic datasets can be collected within a geodatabase, including feature classes, attribute tables, raster datasets, network datasets, topologies, and many others.

Geoprocessing

Geoprocessing is an operation used to manipulate a GIS data resulting in a new set of data. Common geoprocessing operations include geographic feature overlay, feature selection and analysis, topology processing, raster processing, and data conversion. Geoprocessing allows for the definition, management, and analysis of information used to make decisions based on patterns within the GIS data.

Shapefile

An Esri Shapefile is a vector data storage format for storing the location, shape, and attributes of geographic features. A shapefile is stored as a set of related files and contains one feature class. An alternative to using shapefiles to store GIS data is a geodatabase, however, shapefiles have some advantages in terms of relative simplicity and wide-ranging compatibility with many applications. Related files contain additional information that is read by the shapefile when opening/importing in GIS applications, as long as these related files have the same name and reside in the same directory – the *.dbf (database) file contains attribute information, and the *.prj (projection) file contains coordinate system information. Shapefiles also have limitations such as the inability to support raster files, and large file sizes.

Buffer

A zone around a map feature measured in units of distance or time is called a buffer. Buffers are useful for proximity analysis.

Geodesy

Geodesy is the science concerned with the measurement and mathematical description of the size and shape of the earth and its gravitational fields. Geodesy includes the large-scale, extended surveys for determining positions and elevations of points, in which the size and shape of the earth must be taken into account to achieve accuracy.

Vector vs Raster

The terms vector and raster are encountered often in cartography though they are not often defined. In a nutshell,

Raster data is made up of pixels (sometimes referred to as grid cells). Each pixel can have a range of values used to represent data points. For example, in a satellite image, every pixel has a red, green and blue value.  

Vector data is not made up of a grid of pixels. Instead, vector graphics are comprised of vertices and paths where the vertices are x,y coordinates. In GIS systems, they are a latitude and longitude with a spatial reference frame.

Mosaic

A Mosaic is a single raster dataset composed of two or more merged raster datasets—for example, one image can be created by assembling multiple aerial photographs whose edges usually have been torn or cut selectively and matched to the imagery on adjoining images to form a continuous representation of a portion of the Earth’s surface.

Orthorectification

The process of correcting the geometry of an image so that it appears as though each pixel were acquired from directly overhead. Orthorectification is used to correct terrain distortion in aerial or satellite imagery.

Sources

http://wiki.gis.com/wiki/index.php/GIS_Glossary/
https://legacy.lib.utexas.edu/maps/glossary.html
https://gisgeography.com/spatial-data-types-vector-raster/

Carto-Jargon 101: Cartography Terms Defined

The field of cartography is filled with jargon and terminology that can pose a challenge for newcomers learning to use mapping software such as MAPublisher to make beautiful maps, and those who don’t have a formal background in cartography. It also doesn’t make it easier when different software packages have their own variations on certain terms. To help the cause, we have compiled a short list of common cartography terms or “carto-jargon” that you may encounter while using MAPublisher or Geographic Imager.

Basemap

A basemap is a background image which can include aerial imagery, topography, terrain and streets and other fundamental layers and is used as a starting point to create a new map. The basemap is georeferenced and is usually the most accurate source of spatial information within the data system that makes up the finished map. Additional layers of data such as labels, symbols and paths are then added to the basemap to create the final product.  

Feature

Any real-world object that is represented on a map is a feature. Features can encompass large areas of a map, such as bodies of water and mountain ranges, or they can be discreet objects like parking areas, public washrooms or fire hydrants.

Attribute

Attribute data is information about spatial features and is stored in tables. It is also the information that specifies the appearance and labeling of features on a map. For example, the graphic attributes of a river might include the thickness of the line, line length, color, and the name used for labeling.

Control Point

A control point is a location on the map with known pixel (x,y) coordinates. Control points are used in georeferencing to allow for extrapolation of the relative location of other points whose exact coordinates may not be known.

Coordinate System

A coordinate system is a reference system used to represent the locations of geographic features on a map. It provides the basis for identifying locations on the earth’s surface. There are thousands of different coordinate systems, most of which are limited in use to highly specialized purposes.

Projection

The earth is not flat and so imagining that it is for the purpose of putting it on a 2-dimensional map results in some distortion. A projection is a method by which the curved surface of the earth is portrayed on a flat surface and is based on a mathematical transformation of the earth’s lines of longitude and latitude onto a plane. There are many different projections, each of which distorts distance, area, shape, and direction is some way, therefore no projection can result in a perfectly accurate flat map. Check out the Avenza Projections Guide for a more detailed information.

Georeferencing

Georeferencing involves aligning geographic data to a known coordinate system so it can be viewed, queried, and analyzed relative to other geographic data on the same map. Georeferencing may involve shifting, rotating, scaling, skewing, and in some cases warping, rubber sheeting, or orthorectifying the data to improve accuracy.

Graticules and grids

Graticules are the network of longitude and latitude lines on a map or chart that relates points on a map to their true locations on the earth. You can think of this a grid system – in fact, the terms are sometimes used interchangeably, but there is a subtle difference. Graticules are derived from 3-dimensional ellipsoidal shape of the earth and are formed by the the lines of latitude (parallel lines circling the earth), and lines of longitude (non-parallel lines converging at the earth’s poles). A grid system is comprised of a set of parallel and perpendicular lines that are superimposed on a flat projection of the earth, creating an x,y coordinate system. An example of a grid system is the Universal Transverse Mercator (UTM) system.

Themes

In MAPublisher, MAP Themes are a collection of thematic cartography tools designed to automate how styles and symbols are applied, charts are produced, and data is plotted. There are three themes which you can be customized to suit your needs: Stylesheet, Chart, and Dot Density. MAP Themes offer a lot of flexibility as they can be edited, applied, duplicated, automated, exported, and cleared without affecting the spatial referencing of map features.

This is just a small sampling of the more robust glossary of terms available in the our MAPublisher and Geographic Imager documentation packages.

Sources
http://www.avenza.com/help/mapublisher/10.1/index.html?whats_new_in_mapublisher.htm
http://www.avenza.com/help/geographic-imager/5.3/index.html?glossary.htm
https://www.gislounge.com/gis-dictionary/
http://geography.name/gridgraticule/

The Best of Both Worlds – Map-making and GIS Functionalities in Adobe Illustrator

Original article from Directions Magazine on October 4, 2017.


Modern cartography—the art, science, and technology of making maps—consists of manipulating and displaying geographic elements in a graphic environment. Traditionally, GIS software has offered users limited ability to manipulate the graphic attributes (hue, brightness, saturation, transparency, line thickness, text, etc.) of geographic elements, while graphic design software has treated geographic features as it would any other graphic elements, without regard for how they are connected in predictable ways to other geographic elements and to Earth itself. Additionally, in the real world, natural or artificial boundaries and features are constantly changing and cartographers need to update maps at different scales and in different styles to reflect these changes. Therefore, cartographers need an efficient and reliable way to bridge the divide between GIS and graphic design software.

First launched 30 years ago, Adobe Illustrator has long been the professional standard for graphic design, especially for creating vector graphics. For more than 20 years, Avenza’s MAPublisher has provided extensive GIS functionality inside Adobe Illustrator. I discussed the synergy between these two programs with two experts:

  • David Lambert, Director of Cartographic Production for National Geographic’s commercial retail mapping products, which includes its well known Trails Illustrated outdoor recreation map series, and
  • Tom Patterson, Senior Cartographer at the National Park Service’s Harpers Ferry Center, in Harpers Ferry, West Virginia, which designs most of the interpretive media that is found in national parks—including maps, brochures, outdoor signs, visitor center exhibits, films, and digital kiosks.

 

“Map Illiterate” vs. “Map Aware”

Image

In the past, many map makers have also used Macromedia FreeHand (acquired by Adobe in 2005 and since discontinued), CorelDRAW, Canvas, or even more recent entrants with a map-specific slant such as Ortelius, proving that a graphics environment has long been regarded as a good and viable one for their trade. As well, for many years, Esri has offered an Illustrator export option from its GIS products, proving that Illustrator, in particular, has long been the preferred work environment for making maps. However, Lambert points out that those files exported from Esri’s GIS products are devoid of geographic properties once imported into Illustrator. He has been with National Geographic for 21 years. His team used to work with Illustrator, which was already the graphic design standard, but used Esri software to design maps, which they then exported as Illustrator files from Esri and imported to Illustrator. “Once we brought that into the Illustrator format, it lost all geospatial awareness,” Lambert recalls. In essence, the file became “map illiterate.” In 2011, he switched to using MAPublisher after learning how easy it made it to incorporate GIS data into Illustrator workflows.

To explain the advantages of using MAPublisher to keep graphic elements “map aware”, Lambert cites three examples:

  1.  The Great Salt Lake has shrunk in size over the years. “Prior to 2010, somebody would export a lake boundary and then bring it into Adobe Illustrator, where it might be re-scaled and transformed with an Illustrator function to fit the area of another map,” Lambert recalls. Now, with MAPublisher, National Geographic can use the same lake boundary in its maps of Utah, of the United States, and of the world, in each case simply reprojecting it on the fly without having to first export it to GIS software.
  2. Many of National Geographic’s nearly 300 outdoor recreation maps overlap one another at different scales. When, for example, Great Smoky Mountain National Park produces a new trail dataset reflecting changes in trails, National Geographic can now incorporate those changes much more quickly than ever before by simply transforming them through different map projections in the geospatially-aware files.
  3. The boundary between Pakistan and India is constantly changing. National Geographic can now make each change just once, then move it from its world map to its map of Asia and other products.

 

Starting in a Common Projection

Image

National Geographic starts working on any new map products in MAPublisher. “We want to get off on the right foot, so we make sure that they are all in the common projection from the very beginning,” Lambert explains. His team uses MAPublisher right from the start to georeference files and then to incorporate additional GIS data from federal, state, and county agencies into them. “For example,” Lambert says, “if we get a data set from the National Park Service, we are able to quickly import it and split it into the different layers and styles throughout our entire map series. We can see which trails might be hiking trails, horse trails, or mountain biking trails and quickly apply our styles. We also receive information from the U.S. Geological Survey, such as national hydrological data sets.”

MAPublisher allows users to work in a GIS environment from inside Adobe Illustrator. For example, they can bring in a transportation data set from a county, then click on a road in Adobe Illustrator and bring up a MAPublisher viewing panel to display its attributes, such as its name, whether it is paved, and, if it is not, its clearance. “We can see all the information that these agencies are assigning to these different lines,” Lambert says. “Adobe Illustrator and MAPublisher work together seamlessly.” By contrast, he points out, with other programs you have to exit one and go into the other.

Reconciling Conflicting Data

Image

Most of Patterson’s work revolves around making those very familiar black-banded brochures that visitors receive when they enter a national park. He began using MAPublisher in the mid-1990s, when Avenza introduced version 1.0. “We had just started converting our maps from manual production to digital production using Adobe Illustrator as our primary drawing software,” he recalls. “Soon afterward, geospatial data started becoming more available and the quality greatly improved. Of course, we wanted some means to bring these data into the graphic environment of Adobe Illustrator. MAPublisher provided us with the ideal tool for doing just that.”

Early on, Patterson’s team only used MAPublisher to import geospatial vector data into Adobe Illustrator to produce non-georeferenced maps. As the years went by, however, it saw the value of creating entirely geo-referenced maps.

To create a new map of a national park, Patterson’s team begins with an Adobe Illustrator template that contains all of the map layers that it would use for a typical NPS map—including lines, area colors, symbols, and labels. For even greater efficiency, it employs targeted layers with graphical styles applied to them. “A big part of our process at the beginning,” he explains, “is going on an online digital scavenger hunt, essentially finding whatever data we can that is in the public domain, from which we can compile our maps. We then import these various geospatial data sets into the Adobe Illustrator environment with MAPublisher.”

“The most time consuming aspect of map production is reconciling conflicting data,” says Patterson. “For example, analyzing and fixing different road data sources that don’t match with one another is an arduous process. However, thanks to the data manipulation tools in MAPublisher—which allows us to select, sort, and manipulate data by attribute—this task is now much easier.”

Patterson’s team updates NPS maps every year or two or three, depending on each park’s popularity. Working with a geographically-aware MAPublisher document allows it to take the previous printing of its map and import new data into it, which then drops into place where it should. For example, if a park builds a new trail, the park GIS specialist will send Patterson’s team a shapefile for that trail that it can quickly and easily import using MAPublisher. “It just works seamlessly,” says Patterson. Additionally, almost all NPS maps have shade relief art in the background. “We generate the shaded relief and then manipulate it using Avenza’s Geographic Imager tool in Adobe Photoshop. The result is a geographically aware Photoshop file of the shaded relief, which MAPublisher will automatically register to map line work in Adobe Illustrator.”

Geospatial PDFs

Image

Another very important feature of Avenza’s software, Patterson says, is that it enables his team to save all of its printed maps as electronic files in geospatial PDF format for dissemination via the Avenza Maps app and accompanying digital map store direct to digital devices such as smart phones and tablets. Park visitors can then download and use these maps on their location-enabled mobile devices and, because the maps are geospatially aware, a little blue dot will show their location at all times as they explore a park, even in the absence of a cellular data connection.

Before publishing a new map of a national park, Patterson’s team typically field checks it, saved as a geospatial PDF, using the Avenza Maps app on an iPhone. “We refer to this draft map as we canvas the park,” Patterson says. “We can take notes right in the Avenza Maps app, drop locator pins, and record tracks. When finished field checking, we e-mail the data to ourselves and import it into the working map file through MAPublisher. The notes and tracks that we recorded in the field are used to update the final map, improving accuracy.”

One goal of Patterson’s team is to increase online access to NPS maps. “We are pretty excited about some of the new capabilities in MAPublisher,” says Patterson, “particularly, saving our park maps as Web tiles. We are going through a multi-year transformation right now, converting our maps from the UTM coordinate system to the Web Mercator coordinate system for compatibility with Google Maps, Bing Maps, and Apple Maps. We do all of this through the ‘Export Document to Web Tiles’ feature in MAPublisher, which is really pretty cool.”

Patterson’s team also recently began experimenting with MAPublisher’s Map Web Author tool, which allows quick and easy creation of data-rich and interactive HTML5 web maps from GIS data. It produced a prototype for Harpers Ferry National Historical Park that contains layered information and the ability to explore the map interactively. For example, it allows park visitors to compare contemporary photographs to those taken during the Civil War era at various viewpoints throughout the park.

Other Specialized Illustrator Plugins

There are dozens of plugins that extend Illustrator’s capabilities, for example to edit vector data, concatenate multiple paths, or precisely position nearby objects. Here is one list of Illustrator plugins. CADtools and VectorScribe are particularly noteworthy in this context, because they show that a professional base of CAD users like Illustrator as their working environment, just as GIS and mapping professionals do.

HotDoor’s CADtools 10 plugin provides an extensive set of CAD capabilities—including drawing, editing, labeling, dimensioning, transformation, creation, and utility tools—inside Illustrator. For example, users can insert dimensions or labels on objects, paths, or points in space, which update in real time in response to changes in the artwork. The can also move, transform, and measure objects with precision.

VectorScribe enables users to reduce file sizes by eliminating excess points while maintaining the shape of paths; slide points along paths, extends paths, or trim them; accomplish complex vector editing, such as adding points to tangencies, reverse paths, or smoothly connect curves to straight lines; edit corners on dynamic shapes; or dynamically measure distances and areas along paths.

Conclusions

The sources of geospatial data now include unmanned aerial vehicles (UAS), the Internet of Things (IOT), and myriad consumer devices and, consequently, the amount of available geospatial data is growing exponentially. At the same time, professionals and consumers now expect location to be routinely embedded in everything they do on their digital devices. MAPublisher helps cartographers keep up with this accelerating cycle of supply and demand by making it easier and faster for them to make beautiful maps. Recent attempts by other GIS software vendors to address the increasing demand for cartography and map creation within the Adobe environment is evidence that making maps in Adobe Illustrator is the preferred way to go. With MAPublisher leading the way, it is a workflow that is here to stay.

Getting the Best Resolution when Importing an Image from a WMS

Using a Web Map Service (WMS) is a great way to easily get up-to-date imagery for your project. An issue you may run into, however, is that a server may not allow you to download images over a certain size (in pixels). The image resolution provided on most servers is usually high enough for most projects but there may be some instances where a higher resolution is needed (e.g. a poster-sized map or a web map that covers a large area).

One possible workaround for this issue is to get several small-area, high-resolution images from a WMS and then mosaic them together to make one large-area, high-resolution image. Here, we will use the City of Toronto Web Map Service to:

  1. Get an image of downtown Toronto
  2. Tile the image to split it into four smaller images
  3. Use the extents of the four tiled images to get four high-resolution images
  4. Mosaic the images to one large high-resolution image

 

Download an Image from the Web Map Service

First we will get an image of downtown Toronto from the City of Toronto WMS. Click the Advanced Import button on the Geographic Imager panel. Select Web Map Service from the Format drop-down and click Browse. Click Load services from Avenza and select City of Toronto WMS from the list.

 

Download an Image from the Web Map Service
(Click for larger version)

 

Select City of Toronto Imagery from the list of layers. Click Select Area then drag a box to zoom in on an area of downtown. Click OK to return to the previous window. There is no need to change the image size because we will use this image to get the extents of a higher resolution image. Leave the other options as default and click OK to load the image, and click OK again on the Advanced Import dialog box. The selected image will now open in Adobe Photoshop.

 

Tile the Image

Next, let’s tile the image to split it into four separate images. Open the Tile dialog box from the Geographic Imager panel. Choose By Number of Tiles as the Tiling Schema and change Horizontal and Vertical to 2. Change the Horizontal and Vertical Overlap to 3 percent. It’s important to have overlap between the images so they will mosaic properly when the data is transformed.

 

Tile the Image
(Click for larger version)

 

Click the Keep Images Open check box to enable it. Choose a name and location to save the tiles. You can save them to a temporary location because they will not be part of the final product. The four image tiles will open in separate tabs.

 

Estimate a Web Map Service’s Maximum Image Size

Open the City of Toronto Imagery WMS again and select an area. In this service, as with many other services, the maximum resolution is not provided. We can, however, use trial and error to find the largest image that the service will allow us to download. A WMS has a maximum allowed width and height set for an image request. The maximum width is usually the same as the maximum height.

Set the resolution of the image by adjusting the width of the image in pixels under Output Options. First, try setting Image Size to a pixel width of 5000. Height will update automatically based on the image’s dimensions. Click OK and you will see an error that says “Parameter ‘width’ contains unacceptable value” (or height if the images higher than it is wide). OK the error to close it.

 

Estimate a Web Map Service’s Maximum Image Size
(Click for larger version)

 

To estimate the maximum width and height allowed by a web service, you can adjust the image size to see when the server returns an error. The maximum width and height for the City of Toronto WMS is about 4000 pixels.

 

Downloading and Mosaicking Large Images

Next we will use the geographic extents of the four tiled images to download four higher resolution images with matching extents then mosaic the images together. Import an image again from the City of Toronto WMS using Advanced Import. Select an area, click Select Area by Another Document’s Extents and choose the first tiled image from the dropdown menu. The Select Area dialog will display an area matching that image’s area. Click OK to return to the previous screen.

 

Downloading large images
(Click for larger version)

 

Enter 3000 as the Image Size. Click OK to add the image to the Advanced Import dialog box. Repeat the above steps for each of the remaining three tiled images.

Creating a mosaic of four images (two by two) makes a single image just under 6000 pixels wide because of the overlap between the tiles (the height will vary depending on the area you selected). This is larger than the maximum size allowed by the WMS. Check the box Mosaic All Files to the Destination Document and select one of the images currently loaded in the dialog window from the drop-down menu. Leave the other options unchecked and select Normal as the Layer Blending Mode. This will merge the four images into a single document.

 

 

Mosaicking large images
(Click for larger version)

 

Avoid Downloading Images Greater than the Maximum Image Resolution

One further consideration when getting imagery from a service is to avoid requesting an image that is higher resolution than the full resolution of the image on the service. In this case, the number of pixels in the image and, therefore, the image size will increase without any increase in the actual resolution of the image.

To see an example of this, get an image from a WMS by zooming in on a small area and downloading images of varying resolution. The pictures below show two images of the same area side by side at different resolutions. The image on the left is 1024 by 870 pixels and the one on the right is 2500 by 2124 pixels but there is no noticeable difference between them. This is because the image exceeds the resolution of the image on the server so the WMS resamples the image to a higher resolution, creating duplicate pixels.

 

Avoid Downloading Images Greater than the Maximum Image Resolution
(Click for larger version)

 

Use Geographic Imager to Import Imagery from ArcGIS Online Directly Into Adobe Photoshop

With the latest release of Geographic Imager 5.2, it’s now possible to easily import images directly from an ArcGIS Online account or an ArcGIS web service. This will allow you to use shared data within your ArcGIS Online organizational account and connect to publicly available map servers from various online sources.

 

ArcGIS Online is a collaborative web GIS that allows you to store and share GIS data using Esri’s secure cloud. Before, you may have had to download raster layers to your local machine and then import them into Adobe Photoshop using Geographic Imager. Now, Geographic Imager has a much-improved workflow to get ArcGIS Online image layers into Adobe Photoshop with full georeferencing.

Currently, the types of datasets allowed are Map Image Layers and Tile Layers. To load a layer, open Advanced Import and select ArcGIS Online from the Format drop-down list. Enter the credentials for your ArcGIS Online account and select an image layer from your user portal.

Images can be resized and transformed on import. To extract a specific area from the image, click Select Area. The interface is the same as the one used for WMS Import.

In addition to using your own organization’s data, you can connect to publicly available data from a wide variety of organizations by connecting to an ArcGIS Web Service. To connect to a web service, use Advanced Import and select ArcGIS Web Service from the Format drop-down menu. Click Browse and enter the URL for the service. This is a great option when searching for data from open data portals created by government agencies.

Validating Georeferencing in Geographic Imager

When georeferencing a map in Geographic Imager, there are two tools which can be used to check spatial accuracy: Validate and Show Image Extents Online. With Validate, click a point on the image and it will show the corresponding location on the web map service so that you can compare the difference between them. Show Image Extents Online will display a rectangle representing the spatial extent of the image on the web map.

The image below shows the Validate tool in action. Selecting the tool and clicking on the road intersection brings up the same intersection in the web map, displaying how accurate the georeferencing may be. It is good practice to test several known points on the image. Choose features that will be easy to identify on the web map such as road intersections, coastlines, buildings, and landmarks.

The Show Image Extents Online tool is shown in the image below. Use this tool to see the full area covered by the image. Note that the rectangle shown on the web map will include the non-map areas of the page (borders, legend, etc).

 

Avenza Systems Fixed and Floating License Solutions: What Are The Differences?

Avenza desktop applications, MAPublisher and Geographic Imager offer two options for the licensing system: Fixed license and Floating license.

The Fixed license option allows only one license per computer. For most users or small companies, this is generally sufficient, even with a few licenses. Since your license is fixed to a specific computer, it can’t be moved freely to another machine. However, Avenza does allow you to move your license occasionally. For example, if you purchased a new computer or when your computer is being fixed and you need to transfer your fixed license to another computer. If your subscription status for MMP (MAPublisher Maintenance Program) or GMP (Geographic Imager Maintenance Program) is up-to-date, then moving your fixed license to another computer (i.e. rehosting a license) can be done without a cost. Complete this form to do so. You will receive a notification email from Avenza when this is completed.

The Floating license option is for users who wants to share a number of licenses on the network. This is a great solution for any size company that has multiple users who share use of MAPublisher or Geographic Imager. You will need to set up a license server for which users will need check out a license from the server before using MAPublisher or Geographic Imager. In general, this option is used when sharing a number of license with colleagues. For example, the license server holds two seats of MAPublisher license. When users on Computer A and Computer B are using MAPublisher, other users can’t check out a license until the borrowed licenses are checked in.

An example environment of a floating license system

Another great advantage of the floating license the ability to borrow a roaming license with their laptop so that they can use MAPublisher and Geographic Imager outside their immediate office. This is a good solution for users who need to use the software on the go and doesn’t have a connection to the floating license server.

For more information about the licensing options for our MAPublisher and Geographic Imager, contact Avenza sales.

If you have any technical questions about setting up a license server or any other licensing issues, contact Avenza Technical Support.

Working With Avenza Floating Licenses Outside of Your Work Network

If you or your organization have a floating license for MAPublisher or Geographic Imager, this blog post is for you. Having a floating license provides you with a lot of flexibility when you want to bring your laptop computer outside your work network and use MAPublisher and Georaphic Imager at home or in the field.

Let’s say you have a laptop computer and you want to work on your mapping project outside your office network. You can do it if your organization has a floating license.

Step 1: Make sure all the software is installed

On your laptop computer, make sure that you have MAPublisher for Adobe Illustrator or Geographic Imager for Adobe Photoshop installed and that there is a valid floating license (for one or each product).

Step 2: Connect your laptop to the network and to the licensing server

If you are not sure how to connect your laptop to the network and to the server, please contact your IT administrator. It is essential that your laptop computer is connected to the license server so that you can obtain a liecnse from it.

Step 3: Follow the steps in the MAPublisher/Geographic Imager license management window

Open the License Management dialog box.

If you’re using MAPublisher, access MAPublisher by going to Help > MAPublisher Licensing > License Management.

If you’re using Geographic Imager, access License Management by going to File > Automate > Geographic Imager: License Management.

Click the Floating button to open the Floating License Setup dialog box.

Make sure that the “Allow roaming licenses” option is selected. Click OK.

Allow roaming licenses

Click the “Use roaming license” option and specify the number of days in the Duration of borrow option. This indicates how long you want to use the license outside of your network.

Specify duration of borrow

Clicking the “Checkout” button will change the status of the license. In this example, we borrowed a license from the license server for two days (December 16, 2015 starting date).

Checkout the license

Now you will be able to use your MAPublisher or Geographic license when your computer is disconnected from your work network.  You might want to test it by closing Adobe Illustrator or Photoshop, disconnect your computer from the network, restart Adobe Illustrator or Photoshop, and see if you can use MAPublisher or Geographic Imager.

Improve Mosaic By Resampling Images in Geographic Imager

The Mosaic function in Geographic Imager merges multiple georeferenced images together to create a single composite georeferenced image. Though the goal of the mosaic is to create a single and seamless composite image, combining images with the Mosaic tool will often result in a slight shift of the imagery due to differences in the original pixel registration grid. This means that even when images are in the same coordinate system with the same spatial resolution, error can still be introduced because of a difference in the pixel alignment. Due to this, mosaicking processes in general tend to produce results that may be very close, but not exact. With this in mind, the results of your mosaic may be improved by resampling your images beforehand to the smallest unit of the resolution.

As an example, let’s say we have an image where the pixel size is 2.00 metres. When plotting the X coordinates of every pixel in this image (using the top left corner of the pixel), the X coordinate value will be incremented by the number/distance of the pixel size. For example, if the X coordinate values were to start at 111.00, then the next pixel would be 113.00, 115.00, 117.00, and so on. It’s important to note that these coordinate values are discrete, which means that the values could not be 113.22 or 115.77 because the origin of the coordinate in this case starts at 111.00 metres.

Now, we have another image that we want to mosaic with the first image. In this instance, the first image will be “Image A” and the second image will be “Image B”. Image B has the same coordinate system as well as the same pixel size as Image A.

Take a look at the X coordinates in Image A and Image B below:

We can see that the X coordinate in the top-left corner is different between these two images, and as previously mentioned, we know that the X coordinate values are discrete. When mosaicking Image B to Image A, the X coordinate cannot be 111.75 or 113.75. The coordinates must be 111.00, 113.00, 115.00, and so on, following the pattern of the pixel grid values in Image A.

This means that Image B will need to be “shifted” or “snapped” to the closest coordinates when the mosaic is performed, see below:

As a result, the X coordinate of Image B will be shifted by 0.75 metres (less than half a pixel). The pixel with X coordinate 111.75 is now placed at 111.00 and the next pixel with X coordinate of 113.75 will now be placed at 113.00, and so on.

With this in mind, the results of your mosaic may be improved by resampling your images to the “smallest unit of the resolution”. The smallest unit of the resolution can be determined from the difference in the coordinates (spatial alignment difference) between the two images.

Looking back at our example, we can see that the smallest unit of the resolution (represented by the blue arrow) in this case is 0.75 metres – this is the value we will use to resample our images.

Once the images have been resampled to 0.75 metres, we may go ahead with our mosaic.

The above example demonstrates the possibility of a pixel shift after a mosaic for two images with a different pixel alignment. It should be noted that this example explains the problem in one-dimension (looking at only the X coordinate) when the image in reality is in two-dimension (looking at both X and Y coordinates). The basic principal of the pixel shift in 2D is the same, but it would include the direction of the shift when mosaicking images. In addition, it’s important to keep in mind that although resampling your images to the smallest unit of the resolution will improve the final mosaic, this is not always an efficient process when mosaicking with more than two images. Another thing to remember is that resampling your images will make your file size much larger. However, in cases where high precision is desired, resampling the images beforehand is a process that should be considered.

Creating a Super Overlay in Google Earth Pro

Our friends in the map library at Brock University in St. Catherines, Ontario have put together a very nice how-to on creating super overlays for Google Earth using Geographic Imager and Adobe Photoshop.

These instructions describe the process of georeferencing a high-resolution image, creating a geotiff file, using Google Earth Pro to make a super overlay and how to provide access to others. The full process is outlined here https://www.brocku.ca/maplibrary/Instruction/Creating_a_super_overlay.pdf

The Brock University Map Library can be contacted at maplib@brocku.ca