The Problem with 3D GIS

3D GIS is game changing, it can change the way you view your analysis, it can provide insights which you may have overlooked….but there is a little problem which I may had not shared in my deluge of blogs about how great 3D GIS is…..

…Sometimes it can be hard work. What I mean by this, is that it can sometimes need a lot more consideration than standard methods. Let’s look at some of the major culprits when using Esri ArcGIS Pro 1.4 & Desktop 10.5, keeping in mind that there isn’t many (or any) other 3D GIS you can do this kind of work in.

One of the 3D models built of Kendal, UK

Editing

Once you have converted or built your 3D model into a multipatch polygon you may find yourself struggling to edit or adjust your model.

Split

Having built entire cities, one issue that I’ve come across a fair bit is removing parts of multipatch polygons. For example, when adding multiple models, you may find that two features might overlap and need to remove part of one. In a 2D, standard GIS, you would simply turn the editing on and split the offending polygon.

This doesn’t work in a 3D GIS…Think about it, how does the GIS know where all the planes you require breaking lie with a 3D plane? 3D GIS can do some pretty clever assumptions but I am yet to find a way to remove part of a complex multipatch polygon.

True, within ArcGIS Pro 1.4 there are some editing tools for 3D multipatch features but it is early days at the moment. For simple cubes it is quite easy to adjust and manipulate the model a little but you don’t stand a chance if you have a curved edge.

 

Don’t despair, don’t give up on the 3D just yet, as you know, 3D isn’t new and there are many “workarounds”. One of my favourites is using the ArcGIS Pro “Replace Multipatch” tool. If you want to make multiple edits to a model (feature) you can export the multipatch to a collada format or keyhole markup language (kml) format, edit it in Sketchup, Blender, Meshlab or any of your favourite modelling suites and then import it again without affecting the other features in that layer.

 

If you are extruding simple 2D polygons with the intention of creating 3D mulitpatch polygons, it is a good idea to keep the conversion to multipatch until you explicitly need to. This way, you can edit, split and reshape your 2D polygon within normal ArcGIS Desktop without any issues at all and then draw up and extrude when you are 100% sure it all fits and works okay.

 

In my experience, pre-planning and clarity of the end goal means that you can be prepared for these slight niggles in advance.

Using 3D multipatches in ArcGIS Desktop

Overlay analysis 

So, I’ve built out an entire city of 3D buildings, it looks amazing, last thing to do is clip them by the city boundary….oh, I forgot, the 2D polygon doesn’t truly intersect the multipatch polygon in 3D space, the “clip” tool doesn’t work, the “intersect tool” nor the “merge” tool…in fact you can ignore using modelbuilder.

Clip features

I learned the hard way that 3D features work best with 3D features. Unless the boundary polygon is a 3D feature, then you won’t be able to use spatial analysis to use any kind of overlay querying.

But, there is always a way to trick the system…

Although the multipatch polygon feature is a 3D object, you can still open it in ArcGIS Desktop, meaning that you can use the good ol’ fashioned “select by location” tool. No, it shouldn’t work but it does, furthermore, you can then export your selected data to a new multipatch feature. It begs the question why you can do this and not the “clip” as, in geoprocessing terms, they are the same thing (the clip tool is just the separate bits combined into a single script).

Let’s not get too hung up on it, as it works,

Volumetric Analysis

If you thought that the  “volume” tool was just put there to look clever, think again. It can be a great tool for easily representing floor space or calculating the tonnage of aggregate that needs extracting from the ground to lay a new pipeline.

There is a slight problem though…it can be a little hit and miss, especially when using sourced models.

Calculating Volume

Try adding a model you built in Sketchup, Blender or Meshlab to ArcGIS Pro and then calculate volume (using the add z information tool), Nothing, right? But why? The reason is that it doesn’t like “open” multipatch 3D features, it isn’t fully enclosed. Even if there is a slither of a gap in the polygon and it isn’t 100% enclosed, the tool cannot calculate the volume.

There are other methods whereby you can use a raster surface, like the “surface volume” tool but this isn’t quite as accurate as using your super detailed vector multipatch.

You could try the “Enclose Multipatch” tool, as this closes the multipatch and then running the volume tool BUT you need to consider that unless the multipatch is cut to the surface, for example, where a building sits on a hill and the base isn’t perfectly flat, the volume will not be ideal. So please consider using the data as a high resolution TIN which is merged with the terrain to provide a more accurate volume result.

Oh, last point on this – make sure you use a projected coordinate system that uses metric for your data, a geographic coordinate system will leave you with your volume in degrees….is that even possible?!

Which brings me nicely to –

Issues occur when you don’t specify the datum

Vertical referencing

I distinctly remember my first adventures into 3D through Google Earth, trying to create some of Romsey, UK as 3D buildings using Sketchup. The first hurdle was always figuring out whether the building was “Absolute height”, “On the Ground” or “Relative to the ground”…I mean, what does that mean anyway? I just drew it to sit on the floor, why does it need to ask me more questions about it?

Correct Height Placement

Right now, if you are a regular reader of xyHt or a 3D Geoninja, you will be calling me a muppet. In reality though, you wouldn’t believe how often I am asked about this, especially now that Digital Surface Models (DSMs), Digital Terrain Models (DTMs), bathymetry and other elevation data are so readily available.

Elevation is never easy, worst still, there are either too many or too few options. With the Esri ArcGIS Pro, I am 100% confident that I know where my data sits within 3D space but it is only because I’ve worked with this day in and day out and understand the limitations and data sources.

Let’s consider the Esri “scene” – it’s a cool 3D map and as you zoom into that lovely globe you can see lovely mountains and valleys all popping out of the surface, my question to you is, what elevation data is it using? what is the resolution of that data? You see, I love that Esri provide a detailed and complete coverage elevation surface for the entire globe but the flip side of it is that you cannot know the exact limitations of that surface easily (the information is provided by Esri but it is not a simple “point & click” exercise).

My words of advice here are to use your own terrain when placing 3D multipatch features. Therefore you are in control of both the vertical datum and the resolution of the height.

While I’m here, I want to also point out that there isn’t a “snap to ground” feature in the editing tools within ArcGIS Pro either. This becomes an issue when you bring a model in which isn’t vertically reference, has no vertical datum because you then need to sit it on the surface. Even when your model is a captured point cloud and accurate to 0.5cm, you have no way to accurately place it on the ground. You can adjust it up and down and sit it by sight, though you cannot “snap” it.

The big takeaway here is that firstly, you need to ensure you are confident and know your elevation data if you plan to work in the 3D scene views and secondly that you need to set up your x,y & z coordinate systems correctly from the start to ensure that all the work you do is as precise as possible.

…and yes, I now know the difference between “absolute”, “relative to the ground” & “on the ground”….maybe an interesting blog for another day, though feel free to contact me if you need quicker answers!

And everything else

There are still many things I have not had a chance to mention, for example the complexities of cartographic representation using 3D models in a GIS, or ways of minimising the clashing of overlapping data plus other 3D centric issues such as shadow and light. Maybe a blog for another day?….

Dragons8mycat

 

 

How to Grayscale ArcGIS Pro Vector Symbology

Most of the time, ESRI software is great, it does [mostly] what you ask it and as long as you aren’t doing anything too crazy it behaves. We all know that it has it’s ‘unique-ness’ about it, after using it for a few years you start to ask “why don’t they do this….” or “How comes I can’t do that…..”. Well, a lot of this is being addressed in ArcGIS Pro, already it has answered the question as to why we needed 3 different GIS software (ArcGIS Desktop, ArcScene & ArcGlobe) by bundling it all up into one package. Now (with 1.3) we are starting to see other features which we always wanted in ArcGIS Desktop coming into ArcGIS Pro, case in point, converting symbology to grayscale.

Today, I discovered while creating a basemap, that ESRI have implemented a couple of neat little touches, firstly RGB VALUES ON HOVER.

Hovering the mouse provides RGB values
Hovering the mouse provides RGB values

Although this isn’t ground breaking, it is a nice little touch which, for us cartophiles and OCD cartographers, provides a quick and easy bit of feedback.

The other discovery was having the option to grayscale the symbology. The new ArcGIS Pro can be a little tricky to get your head around, so it is understandibly not obvious but I went to change the RGB values on a piece of road and found another option: GRAYSCALE

Grayscale dropdown
Grayscale dropdown

Selecting “Grayscale” takes you to this menu:

Grayscale removes colour while retaining it's presence.
Grayscale removes colour while retaining it’s presence.

 

Okay, so this isn’t groundbreaking BUT having played with photoshop a little, I’ve found that the RGB value which is automatically given is almost a perfect match for what you get if you desaturate the colour.

What does all this mean? It means that you can easily and confidently convert your vector symbology to grayscale without guesswork! Creating alternative grayscale maps should now be a lot easier! Now, the question is, will this ever make it to ArcGIS Desktop?!

Dragons8mycat

GIS Tips: Make QGIS DEMs more “3D”

Applying a hillshade effect to QGIS DEMs

Relief shading gives a DEM a more “3D” look. In the popular ESRI ArcGIS, there is a function to apply “z” amplification to the hillshade effect, this is quite easy to replicate in QIGS.

To use relief shading in QGIS, follow the steps outlined below:

Ensure that you have your DEM open in QGIS, and have an appropriate colour map shading. The DEM without relief shading is shown below.

QGIS relief shading 01.png

From the menu items select – Raster >>> DEM (Terrain Models)

Select the input DEM, and an output filename (a new hillshading DEM will be created). Make sure the Mode is set to Hillshade.

QGIS relief shading 02.png

Open the output file. Position this in the Layer Control section above the DEM, and set a transparency for the layer.

QGIS relief shading 03.png

The DEM should now have relief shading, the relief shaded DEM is shown below.

QGIS relief shading 04.png
Nick D

GIS Tips – Repair broken links using python

I’m not going to lie, I don’t like python, probably because I’m turning into my dad and slowly find myself finding things a little harder to learn….I think being able to cope with C++, C#, VBA, HTML, CSS, Ferranti Fbasica, Cobal & (My favourite) Sinclair Basic, should be enough for anyone, python just tips me over the edge.

What grinds me even more though, is the ArcGIS broken links…even when you have the relative paths set, it still throws a fit every now and again and you lose all the links.

Of course, it should be easy, we all know about the trick of clicking on the red exclamation mark so that we can relink all the data again, don’t we? Here is a quick refresher fromt the ArcGIS help page:

From ArcGIS 10.0 help page 30th November 2013

When you open a map, ArcMap looks for the data referenced by each of the layers in the map. If ArcMap can’t find the data source for a particular layer, that layer won’t be drawn. You can immediately tell whether a layer on your map has a broken data link because it will have a red exclamation point next to its name in the table of contents, and the check box next to the layer will be unavailable.

Broken data link in the table of contents

A layer needs repairing if the data source it references has been moved, renamed, or deleted or is inaccessible for some other reason.

There are a number of ways to repair broken data links, which are described in the following sections:

Repairing a broken link for one layer

If you only want to repair a broken link for a specific layer, click the Set Data Source button on the Source tab of the Layer Properties dialog box.

Click the Set Data Source button to enter the correct dataset location.

This lets you specify the layer’s data source by browsing to it. Select the desired data source on the Data Source dialog box and click Add to repair the layer.

Repairing broken links for multiple layers

You may find that several layers in your map need repairing. For example, if a geodatabase containing data sources that are used for multiple layers in your map has been moved or renamed, all these layers will need to be repaired. If you want to repair several layers at once, right-click the layer with the broken link and click Data > Repair Data Source. You can also click the red exclamation mark to open the Set Data Source dialog box as shown here.

Repairing multiple data links

When the repair to the data link is made from the table of contents, ArcMap repairs the selected layer using the data source you browse to and automatically repairs other broken layers if it can find their data sources in the same location of the data source you specified.

Repairing broken links using python

Now, even with my limited python ability got the following to work. In this scenario, the data was located directly under the C:\Project\Data folder but was moved into a subfolder called Data2. This script updates a single map

 
document.import arcpy mxd = arcpy.mapping.MapDocument(r"C:\Project\Project.mxd") 
mxd.findAndReplaceWorkspacePaths(r"C:\Project\Data", r"C:\Project\Data2") 
mxd.saveACopy(r"C:\Project\Project2.mxd") del mxd
 

Easy peasy, but to be honest this may just be as easy as clicking on the red exclamation mark in most scenarios. But what if you tranformed all the data from shapefiles into your geodatabase?…This is where the python excels (using the exclamation mark method won’t work for this)

Re-linking data that has changed formats

This scenario involves updating two different workspaces in a map document. First, shapefiles are redirected to a file geodatabase called Parcels.gdb. Second, layers from a personal geodatabase are redirected to another file geodatabase called Transportation.gdb.

import arcpy mxd = arcpy.mapping.MapDocument(r"C:\Project\Project.mxd")
mxd.replaceWorkspaces(r"C:\Project\Data", "SHAPEFILE_WORKSPACE", r"C:\Project\Data\Parcels.gdb", "FILEGDB_WORKSPACE") 
mxd.replaceWorkspaces(r"C:\Project\Data\Transportation.mdb", "ACCESS_WORKSPACE", r"C:\Project\Data\Transportation.gdb", "FILEGDB_WORKSPACE") 
mxd.saveACopy(r"C:\Project\Project2.mxd") del mxd

That wasn’t so painful was it? Before I sign off, I have to credit TeachMeGIS.com for the inspiration for this post, as the first python script I reference is based on one which they posted way back in 2011 for ArcGIS 10.0Nick D

GIS Tips – GIS and the Law

I love my job, whether creating works of art or building a new tool for automating some mundane task, it keeps me busy and stops me from causing trouble. One thing I don’t enjoy though, is the legal side of GIS.

Every data has a source, which someone, somewhere has created and owns rights to that data. A typical map or cartographic representation may contain 10 to 20 of these layered data sources….so where on the limited space do you put all those sources, furthermore, who are they? They were probably supplied by your line manager who got them from a sub-contractor who got them from a surveyor who nobody got the name of……

There are a wealth of books on this subject, I know, I have all 4 of them and was looking to write one myself, probably entitled something like “Before you publish your map, caveat EVERYTHING”, until I came across the Maine University website for the “First Readings of GIS Law“.

There are some great resources here and references to books which I have only heard of. Please have a read of some of the page below.

Written by Professor Harlan J. Onsrud of University of Maine.

GIS Law

First Readings in GIS Law

Note: The readings referenced in the following paragraphs are recommended for obtaining an initial overview of the legal issues surrounding the use and development of geographic information technologies and databases. HJO

The use of geographic information technologies is pervasive throughout business, government, industry and the scientific community in the United States. Conflicts are arising on a daily basis for those using geographic information systems and their affiliated databases, for those implementing such systems, and for those designing the next generations of spatial information technologies. Balancing among competing interests and resolving conflicts involved in the use of these technologies are growing problems for numerous parties within society. Among the problem domains of greatest concern in use of these technologies are those involving personal information privacy, intellectual property rights in geographic information, liability in the use of geographic data sets, public access to government geographic data sets, public goods aspects of geographic information in libraries, and sales of geographic information by government agencies.

Conflicts in regard to personal information privacy have become much more pervasive throughout the geographic information community within the past few years. Clarke (1999), Marx (1998), Hernon (1997), Curry (1997), Ontario (1997) and Onsrud et. al. (1994) provide more extensive discussions of the range of privacy conflicts in the use of geographic information. There also is a burgeoning literature on information privacy issues generally. A search of “information privacy” on Uncover reveals over 400 professional journal articles published in just the past two years alone. Also witnessing unprecedented growth in addressing information privacy issues are books, government reports, conferences and web sites (respective examples include book: Agre and Rotenburg (1998), reports: U.S. Dept of Commerce (1997), U.S. Senate Judiciary Committee (2000) conference: Cyberspace or Privacy: A New Legal Paradigm? http://www.stanford.edu/group/lawreview/symposium/index.html/, and web site: http://special.northernlight.com/privacy/index.html).

For a discussion of conflicts and societal harms related to competing claims over intellectual property in geographic information (i.e. copyright, other IP, and additional ownership claims based on contract or database legislation), see NRC (1999a), NRC (1999b), Onsrud and Lopez (1998), Pluijmers (1997), Silverstein (1996), Karjala (1995) and Cho (1995).

Liability issues and conflicts over responsibility for damages in the event of harms caused through the use of spatial technologies or databases are explored in Onsrud (1999), Schultz (1999), Stewart, et. al. (1997) and Phillips (1996).

Public use of and access to government geographic databases is often the test case in local jurisdictions for resolving conflicts over access to government data generally. Such cases involve complex sets of tensions between citizens, government officials, non-profit groups and the commercial sector. Access to government geographic databases and the conflicts to which they give rise are discussed in Onsrud (1998b), Onsrud (1998c) and Lopez (1996) while access to government databases in general are discussed in Weis and Backlund (1997). (See also Los Angeles (1999)).

To treat the works in geolibraries foremost as commodities harms other valuable societal functions of information. Conflicts and tensions between the “public goods” and “private commodity” aspects of geographic data in library or library-like online settings are discussed in NRC (1999c) and Onsrud (1998d).

Finally, the sale of geographic data by government agencies and the imposition of restrictions on the use of data gathered at taxpayer expense continues as a highly contentious issue in jurisdictions across the entire nation as discussed in Perritt (1995), Onsrud et. al. (1996), Onsrud (1998a), and, generally, NRC (1999a&b).

GIS Law Webcast Lectures

The following lectures were presented in SIE525 Information Systems Law at the University of Maine during the fall of 2001.  View the videos using recent free versions of Netscape and Quicktime.  Consult access, software, and hardware requirements if you have difficulties.  Streaming video lectures and accompanying slides are available on the following topics:

Liability for Geographic Data, Products and Systems  Lectures 3, 4 and 6

Ethical Issues in the Use and Development of Information Systems  Lecture 5

Privacy and the Use of GIS  Lectures 7, 8 and 9

Intellectual Property Basics  Lectures 11, 12 and 13

Database Protection and Academic Research Lecture 14

Copyright, Copyleft and Evolving Concepts  Lectures 15 and 16

Public Information: FOIA and Open Records Laws  Lectures 17 and 19

Access, Use and Ownership Issues Surrounding State and Local Government Databases  Lecture 20

Evidentiary Admissibility of GIS Products  Lecture 22

Developing a Public Library of GIScience  For the webcast, see Duke Law School Conference on the Public Domain under Subject Study Area 2.  Use recent free versions of Explorer and Real Player.  For the example referred to in the lecture, see Public Library of GIScience.

References Cited Above

Agre, Philip E. and M. Rotenburg, 1998, Technology and Privacy: The New Landscape (Cambridge: MIT Press).

Carson, C., 1997, Laser Bones: Copyright Issues Raised by the Use of Information Technology in Archaeology. Harvard Journal of Law and Technology, 10(2), 281-319.

Cho, G., 1995, Legal Dilemmas in Geographic Information: Property, Ownership and Patents. Journal of Law and Information Science, 6(2), 193

Clarke, Roger, 1999, Person-Location and Person-Tracking: Technologies, Risks, and Policy Implications. Information, Technology and People, http://www.anu.edu/people/Roger.Clarke/DV/PLT.html

Curry, M.R., 1998, Digital Places (New York: Routledge).

Hernon, P. and R. Duncan, 1997, GIS and Privacy. Journal of Academic Librarianship, 23(6), 515

Karjala, D., 1995, Copyright in Electronic Maps. Jurimetrics, 35(4), 395-416.

Lopez, X., 1996, The Impact of Government Information Policy on the Dissemination of Spatial Data. PhD Diss., University of Maine.

Los Angeles Police Department vs. United Reporting Publishing, U.S. Supreme Court, No.98-678, decided Dec. 7, 1999. (State law upholding authority of local government agencies to maintain open access to public records while limiting the First Amendment rights of corporations to use government databases for commercial purposes. See also Charles L. Black, Jr., former Dean of Yale Law School, “A New Birth of Freedom” in regard to development of new human rights for citizens as superior to corporate rights)

Marx, G. T., 1998, Ethics for the New Surveillance. The Information Society, July, 14(3), 171

National Research Council (NRC), 1999a, A Question of Balance: Private Rights and the Public Interest in Scientific and Technical Databases. Committee for a Study on Promoting Access to Scientific and Technical Data for the Public Interest, Commission on Physical Sciences, Mathematics, and Applications (CPSMA) (Washington D.C.: National Academy Press).

National Research Council (NRC), 1999b, The Digital Dilemma: Intellectual Property in the Information Age. Committee on Intellectual Property Rights in the Emerging Information Infrastructure, Commission on Physical Sciences, Mathematics, and Applications (Washington D.C.: National Academy Press).

National Research Council (NRC), 1999c, Distributed Geolibraries, Panel on Distributed Geolibraries, Mapping Science Committee, Commission on Geosciences, Environment and Resources (Washington D.C.: National Academy Press).

Onsrud, H.J., 1998a, Loss of Legal Access to Geographic Information: Measuring Losses or Developing Responses? In Janelle, D.G. and D. Hodge (Eds.), Information, Place and Cyberspace: Issues in Accessibility (Berlin and Heidelberg: Springer-Verlag) 2000 – In press. 1998 version at (www.artsci.washington.edu/varenius/)

Onsrud, H.J., 1998b, The Tragedy of the Information Commons. In Taylor, F. (Ed.), Policy Issues in Modern Cartography (Oxford: Elsevier Science) 141-158.

Onsrud, H.J., 1998c, Access to Geographic Information in the United States. Free accessibility of geo-information in the Netherlands, the United States, and the European Community, Proceedings, Oct 2., Delft, Netherlands, 33-41.

Onsrud, H.J., 1998d, Balancing Intellectual Property Rights and Public Goods Interests in Geolibraries. Fédération Internationales des Géomètres (FIG), Brighton England, July 25, 1998, 3, 222-226. (Based on earlier presentation to Conference on Geolibraries, Mapping Science Committee, National Research Council, June 15, 1998, Washington D.C.)

Onsrud, H.J., 1999, Liability in the Use of Geographic Systems and Geographic Data Sets. In Macquire, Goodchild, Rhind, and Longley, (Eds.), Geographic Information Systems: Principles, Techniques, Management, and Applications (New York: Wiley).

Onsrud, H.J. and X. Lopez, 1998, Intellectual Property Rights in Disseminating Digital Geographic Data, Products, and Services: Conflicts and Commonalities among European Union and United States Approaches. In Masser, Ian and Francois Salge, (Eds.), European Geographic Information Infrastructures: Opportunities and Pitfalls (London: Taylor and Francis) 153-167.

Onsrud, H.J., J. Johnson, and X. Lopez, 1994, Protecting Personal Privacy in Using Geographic Information Systems. Photogrammetric Engineering and Remote Sensing, LX(9), 1083-1095 (ESRI Award for Best Scientific Article in the Journal – 1994).

Onsrud, H.J., J. Johnson and J. Winnecki, 1996, GIS Dissemination Policy: Two Surveys and a Suggested Approach. Journal of Urban and Regional Information Systems, 8(2), 8-23.

Ontario Office of Information and Privacy Commissioner, 1997, Geographic Information Systems (April 1997) http://www.ipc.on.ca/web_site.eng/matters/sum_pap/summary.htm

Perritt, H., Jr., 1995, Should Local Governments Sell Local Spatial Databases Through State Monopolies? Jurimetrics, 35(4), 449-469

Phillips, J., 1996, Information Liability: The Possible Chilling Effect of Tort Claims Against Producers of Geographic Information Systems Data. Florida State University Law Review, 26(3), 743

Pluijmers, Y., 1997, Protecting Intellectual Property in Private Sector Spatial Datasets. MS Thesis. University of Maine.

Schultz, R., 1999, Application of Strict Product Liability to Aeronautical Chart Publishers. Journal of Air Law and Commerce. 64(2), 431-460.

Silverstein, M., 1996, The Copyrightability of Factual Compilations: An Interpretation of Feist Through Cases of Maps and Numbers. Annual Survey of American Law, 147-218.

Stewart, K., G. Cho and E. Clark, 1997, Geographical Information Systems and Legal Liability. Journal of Law and Information Science, 8(1), 84

U.S. Department Of Commerce, National Telecommunications and Information Administration, 1997, Privacy and Self-Regulation in the Information Age. http://www.ntia.doc.gov/reports/privacy/privacy_rpt.htm

Weiss, P.N. and P. Backlund, 1997, International Information Policy in Conflict: Open and Unrestricted Access versus Government Commercialization. In Kahin, B. and C. Nesson, (Eds.), Borders in Cyberspace (Cambridge: MIT Press) 300-321

Whitman, D., 1999, Digital Recording of Real Estate Conveyances. John Marshall Law Review, 32(2), 227-268.

GIS Tips – Speed up ArcCatalog Start Up

Disconnect your folders!! Why?

When you open ArcCatalog, a set of entries are inserted into the Catalog tree and a complete scan of your connected folders occurs to identify files of the type you’ve instructed ArcCatalog to show. Of course, many of us may not be aware that we instructed ArcCatalog to do such a thing because we just accepted the default installation.

If you open the Options form from the Tools menu and look at the General tab you’ll see two list boxes. The first contains the top level entries you want the Catalog to contain. The second contains the types of data you want the Catalog to show. By default, all items in these two lists are selected. However, there’s a good chance that you may never need some of them. Thus, it makes sense to tell ArcCatalog to ignore entries and items that are of no interest to you by unchecking them in these lists.

In addition, there’s no sense in having ArcCatalog search for items in folders that you know will never contain GIS datasets. So, it’s a very good idea to remove the connection to the root folder of your drive from the Catalog tree along with any other connections to folders that may lead to unnecessary scanning. Then add as many connections as required to folders containing GIS data. As you should see, adopting this process can lead to a huge improvement in the speed at which ArcCatalog open

This method can also be applied to the ArcGIS desktop software also, you may notice that when you open a fresh ArcGIS session that there is the option to open the session from a large list of your connected folders.

Nick D

GIS Tips – Create and Share layer packets (.lpk) in ArcGIS Explorer

I’ve currently been inundated with projects that need the ability to share GIS data in their projects and most of them don’t really understand why they pay £10,000 for a survey and then £75k – £100k for a server solution to share it, let alone understand what GIS really is and WHY they need it in their business.

So, I usually find myself starting small and then slowly feed more functionality to the client as they start to understand what it is the system really does.

Today, I was doing just this, a project worth £Billions and they knew they needed GIS but not entirely sure WHY, so out came the good old ArcGIS Explorer, a little less scary to look at for the average client and enough like Google Earth to make it easy to pick up and run. The only issue I ever had with it was that it wasn’t fully compatible with ArcGIS, by that I mean that ESRI could have gone the extra mile and provided an mxd to nmc converter or at least ensured it used the same format for hyperlinks as the ArcGIS. Though these are small grumbles for what in essence is a great piece of software that can easily convince people to un-install Google Earth.

Anyhow, enough about how great this tool is, during my presentation the client asked whether there was any way that they could mark and update things on the map and I talked them through the “notes” tool and how they could be sent and brought into ArcGIS….as I said this I noticed another option, save the note as a layer package…..amazing!!

I’m not going to go into too much detail otherwise I would be doing myself out of a job, but lets just say that with the ability to have interactive maps on a Google Earth type GIS viewer that uses KMLs, GDBs, SHPs, GPX amongst some of the formats, has imagery layers, open street map topography layers, provides the user with query, measure & geocoding tools AND has the option to allow the user to create their own data which can be sent back to the GIS controller…..well you can see the value of this.

Many of you are sat their thinking about the options like ArcGIS Online – This has feature size restrictions at the free end or is the cost of an ArcGIS licence at the basic end….some of you may be wondering why I don’t just set up a web map – This may be a shock but some of use don’t have masses of server space or can outlay the money for web hosting based on a potential project……and the rest of you who are wondering why I haven’t just used QGIS – Simply too scary for the average Project Manager, in fact I have always wondered why there isn’t a QGIS “viewer” option that is more straight forward for younger wannabe GIS stars or those who need a little more functionality than Google Earth.

To get back on track, the core of this post is to say that you can save drawings on the ArcGIS Explorer as layer packets, for more information on how to do this, it is all here on the ESRI ArcGIS Explorer Resources page:

Sharing notes as layer packages

A new feature in the latest release (build 1500) of ArcGIS Explorer is the ability to share (export) notes as layer packages.Notes have always been an easy and powerful way to add non-geographic content, such as photos, documents, movies, websites, and more to your map. Now those same notes can be shared as layer packages to use in ArcMap. Let’s take a closer look…

We’ve placed a point note in the middle of the Esri Redlands campus and added a link to the Esri website in the note popup. Here’s what the popup looks like:

To share this as a layer package, right-click the note in the map contents and choose Share…

You’ll be presented with a couple of choices to make. First is the format for sharing. The choices are: as an Explorer map content file (.nmc), layer package (.lpk), or KML. We’ve choosen Layer Package in this example.

Next, you’ll have a choice of how you want to share the layer package. You can share it as a file, E-mail it, or add it to ArcGIS Online. We’ve chosen File.

Layer packages require a description, and when sharing one from Explorer you’ll be automatically prompted to add one:

After completing the above steps, you’ll now have a layer package, in our case one named Esri Redlands.lpk, saved to the folder you specified.

Next we’ll start ArcMap and add the layer package we’ve just created. In ArcMap layer packages are not yet supported using Add (that’s coming in the 10.1 release) but we can drag-and-drop our layer package into the map document instead. We’ve also added the World Topographic basemap from ArcGIS Online to get our map off to a good start. After drag-and-drop, the layer package will be listed in our contents:

To display the popup window we use the HTML popup tool, which was introduced at the ArcGIS 9.3.1 release.

Use the HTML popup tool to click the note in ArcMap to display the popup contents – it’s just like the original Explorer note.

For more information view the sharing layer packages Explorer help topic