Category: 3D GIS
We’ve recently had a few users contact us asking why they
have upside-down labels appearing in ArcGIS Explorer or ArcGlobe. We figured it might help if we explain the
technical reasons behind this phenomenon, and the ways to avoid it, in this
week’s blog post.
So, why are labels
not rotated to the north? Why don’t the
labels spin themselves to the correct angle?
The first thing to know is that this issue only happens with dynamic Map Services. This
particular publishing method takes a request from the viewing application (ie:
Explorer or Globe) and returns the tile in the native coordinate system (which
is Cube). A side effect of this process
is that the service effectively “burns” the labels into the map in the
destination projection – Cube. (This process
of “burning in the labels” is kind of like climbing on to your house and
painting your name on the roof – it locks the text in at that angle). The problem is that in some places in the
world, the map is burning the labels in at the wrong angle.
But why? ESRI knows
which way is north, right?
We do, but the
dynamic map service uses ArcMap (2D) display
logic to create the requested display, therefore labeling objects for the Cube projection
in a way that makes sense in 2D and not 3D.
Let’s look at a graphic. Here’s what the Cube projection looks
like in ArcMap. It’s like a box that folds in on itself for display one a 3D
globe. Note the locations of the North
and South Poles – in the center of the top and bottom sections of the cube.
The Cube Projection, as displayed in ArcMap
Let’s look closer at the North Pole area. You
can see how there are actually four sections inside the polar faces, and that
the “north” direction is separated into four regions (triangles). Note that the labels are appropriate
(readable) for viewing this in 2D.
The blue arrows indicate the north direction within each triangle
If we think about those triangles rotating into
place (to honor their true north direction) it’s possible to grasp how the
labels are being displayed with 90-degree rotation in Greenland, 180-degree
rotation (upside-down) in Europe, and 270-degree rotation in eastern Russia.
Rotating the polar sections so they display a
consistent north direction.
OK, so now you understand the technical details of what
But most likely you only really
care about how to fix it. There are a
number of options to publish services that AVOID this issue. A few of the
simpler workarounds include:
Fully cache the Map Service (in, say, WGS84 or
Fully cache a Globe Service
Create a fully cached vector Globe Service for the labels (point features only), and publish
the non-labeled layers as a Map Service
Of these options, you may find that the third provides the best
final display. While it does require the
creation and maintenance of an extra service, the display of billboarded labels
in 3D is usually the most effective.
ArcGIS 10 allows you to do sketching and analysis in a 3D environment, across scales. For example you can sketch a urban development in 3D and run a number of 3D analyses on it to determine optimal design.
Have a look at this video on our 3DGIS Resource Center. It shows a mock planning process for doing a transit oriented redevelopment project. It demonstrates some of the new capabilities of ArcGIS 10 to do sketching and analysis in a 3D environment and across scales. The video was developed as a technological demonstration to provoke thought about how we can better integrate geography into our design practices.
If you are interested in learning more, please visit the GeoDesign Summit website and get involved in exploring, developing, and changing the way we design our world.
Gert van Maren
3D Product Manager
We’ve launched a new section on our web site that is focused on showcasing presentations on various topics relating to the geospatial technology field.
Have a look at the 3D presentation during the 2010 User Conference Plenary.
See how 3D GIS is used to analyze virtual city models to consider the impact of a proposed redevelopment project. The 3D editing environment provides answers about visibility concerns and the impact of building shadows on neighboring buildings.
Gert van Maren
3D Product Manager
Come visit us at ELMF in The Netherlands:
This two-day technical conference will focus on the use of lidar to support transportation, urban modeling, and coastal zone and asset mapping. Esri will demonstrate how to manage large amounts of three-dimensional spatial information using the ArcGIS system of GIS products. ArcGIS accurately represents and extracts feature information from lidar, 3D laser scanning, and other remotely sensed data types; ties it to specific locations; and integrates it with other spatial data for analysis and sharing. Use ArcGIS and the ArcGIS 3D Analyst extension for the ability to model the world as it should be, in 3D.
You can find development staff at booth 26!
A lot of users need to be able to edit the geometry of their 3D objects or add/update the textures. Up until now this was a pretty cumbersome process. At ArcGIS10, this work-flow becomes much easier. Basically it comes to:
- export the object you need to modify from ArcGIS as a COLLADA model
- use the 3D modeling package of choice (for example SketchUp) and
- replace the old geometry with the new one in an ArcGIS edit session.
Another good resource are these videos from Gary Smith, President of Green Mountain GeoGraphics.
They show similar ArcGIS <-> SketchUp work-flows.
- Converting SketchUp 8 models to ArcGIS 10 Multipatch features
- Updating a Multipatch Feature using SketchUp 8
Gert van Maren
3D Product Manager
3D Analyst 10 makes ArcGIS a complete system for 3D GIS.
That is a big statement so let me explain. Not only can you view your geospatial data in 3D Analyst, at 10 you can edit your data in 3D and analyze your data in 3D. Now that is pretty huge. Most companies focus on 3D visualization of geospatial data and some are very good at it. However you can only look at your data on a globe for so long. After awhile, the WOW factor starts wearing off and you’ll want to edit and analyze your data in 3D. This is what makes 3D Analyst different from 3D viewers.
So what does that mean: Edit in 3D and 3D Analysis?
We have enabled the standard ArcGIS editing environment inside both ArcGlobe and ArcScene. You can create and delete individual features, move, rotate, scale and replace feature geometry. This includes the ability to place 3D models (e.g.: COLLADA files) directly into the 3D view as new multipatch features, and then move / scale / rotate them on the landscape. All the standard editing options – Undo, Redo, Edit Templates, etc – are supported, as is the classic Snapping environment.
We’ve also made huge improvements in the analysis of 3D vector features. We have added 3D boolean operators such as Intersect 3D, Union 3D, Difference3D and Inside 3D to be used with closed multipatches, new GP tools that expose 3D vector analysis specifically for virtual city workflows, such as Skyline and Skyline Barrier and enhanced existing GP tools to work better with 3D – ‘Select by Location’ dialog uses 3D distances, multipatch objects can participate in the Line of Sight tool.
edit in 3D Analyze in 3D
So what does this all mean?
It means that 3DAnalyst 10 is a big leap forward for the handling of 3D GIS data. Not only can you view huge volumes of your data in 3D, you can edit your data in 3D, analyze it in 3D and easily share it with your colleagues or the public.
That sounds great but what can you actually do with it?
I’ll get into that in more detail next time.
Gert van Maren
3D Product Manager
the new 3DGIS resource center! Here you’ll find information on how to work with
It features a collection of down-loadable templates that show you how to perform
common 3DGIS work-flows, example videos explaining some of the problems you can
answers with 3DGIS, links to the 3DAnalyst Forum and the Ideas site, pointers to key
areas of the Desktop Help and of course this blog.
be added/updated on a regular basis by the 3D development team. Our goal is to
make this resource center a valuable asset for anybody working with 3DGIS.
Please note, all template work-flows
and video examples are based on ArcGIS10.
3D Product Manager
Often the author of layer packages is using ArcMap and 2D symbols that drape, instead of billboard, when viewed in 3D mode in ArcGIS Explorer. Here’s some great information from Mark Bockenhauer in a recent ArcGIS Desktop blog post about how to author layer packages that work well in both display modes.
OK, so the title is a bit misleading, but we have been hearing from a few of you in regards to getting layer packages to display with 3D points in ArcGIS Explorer, and there is a way to do this using ArcMap. The quick answer is to use a Layer or Layer Package that already has the desired 3D layer properties. Simply, add a layer with 3D properties to ArcMap and reset the data source for the layer to your point feature data. While you cannot set 3D properties for a layer in ArcMap, if the layer already has 3D properties, ArcMap does not remove them.
For those of you that know how to reset the data source on a layer in ArcMap, you are set… you just need a point layer that already has 3D properties. I have made one that has the basic settings for 3D points that most people want and you can get it here. The 3D properties will work well for general visualization of points in 3D and 2D. A full explanation of the details follows below…
The issue: points from an ArcGIS Layer appear flat (draped) and are too big in ArcGIS Explorer 3D
For an example we will take a look at a default layer from ArcMap. In this case I have added point features representing cities in the United States (orange points). I also have a shaded relief basemap loaded in for reference.
If we create a layer package (see help for creating packages) out of this layer and open it in ArcGIS Explorer we will see the following:
In ArcGIS Explorer 2D, it looks pretty good. The layer has 2D properties and ArcGIS Explorer displays it as it is seen in ArcMap. If we switch to 3D in ArcGIS Explorer we see that the points are displayed in a larger size.
If we zoom in on the map we also see that the points are too big and they are draped on the surface.
This occurs because the layer does not have good 3D properties for this ArcGIS Explorer use case. Using the layer package referenced above this can be corrected. Open this layer from ArcGIS.com in ArcMap.
Right Click on the layer and open the layer’s properties…
On the Source Tab click the ‘Set data source’ button and browse to your point data.
If we create a layer package from this layer and open it in ArcGIS Explorer 3D, it looks like this:
The symbols have better sizing for this use case and they display in 3D.
In ArcMap we can adjust the layer properties further, changing the layer name, symbol, symbol renderer, turn on labels, set HTML popup etc… While 3D marker symbols like those in the ArcGIS_Explorer style work well, you can also use ArcMap’s character marker symbols . For example, I changed the layer name, chose the ‘Hospital’ symbol from the ESRI style and changed the size from 18 to 14.
In ArcMap it looks like this:
In ArcGIS Explorer 3D it looks like this:
If you have a 3D Analyst license you can use the layer as template in ArcGlobe. Of course, you can also use ArcGlobe to adjust the layers 3D settings and do more advanced 3D display.
Content for this post provided by Mark B. (ArcGIS Explorer Team)
ArcGIS 10 is close to being released and along with ArcGIS 10 will be a new release of ArcGIS Explorer (build 1500). We’re not going to list the new features in the 1500 release yet (and there are some surprises) but we thought it would be interesting to visit one of them – the enhanced capability to visualize virtual cities. Here’s an example that team member Mark Bockenhauer shared.
Shown below is what may have been considered state of the art a while ago – extruded building polygons based on height attributes with a little creative color shading thrown in. While not the ideal, this method was low-overhead and complete cities could be authored and served quickly, and viewed efficiently using ArcGIS Explorer.
Using automated capture of building facades and heights and draping them onto buildings is a much more realistic approach that’s been possible to do in ArcGIS for while, but has also been somewhat constrained by the overhead of displaying all that data and service throughput.
Shown below is the result of some work that’s gone into the ArcGIS 10 3D Analyst (ArcGlobe) and ArcGIS Server globe services. These improvements, coupled with enhancements to ArcGIS Explorer 1500, make it easier, faster, and more efficient to create and view entire virtual cities from 3D ArcGIS services using Explorer.
In the example below facades were captured using oblique aerial imagery (through Pictometry) and then draped onto 3D shapes. The geometry and textures were automatically generated from the imagery, building footprints, and LIDAR (via Pictometry’s partner, Precision Lightworks).