Tag Archives: Imagery

What’s New ENVI 5.4 and IDL 8.6

Harris Geospatial has released their newest version of ENVI 5.4 and IDL 8.6. With every release Harris Geospatial is improving their platforms to ensure that ENVI and IDL remain at the forefront imagery Analysis. Here is an over view of all the NEW changes to the Harris Geospatial product suite.This post will provide an overview of the following; Licensing changes, new ENVI functionality and new IDL functionality.  Continue reading

Making your drone work for you

When the term drone is used it often conjures up images of installations being destroyed by laser guided bombs or unmanned military surveillance aircraft being used to spy on strategic targets. However, the drone of today is more than this. They have come down in price and size. To the extent that we can now purchase a drone or as CASA prefers a Remotely Piloted Aircraft System (RPAS), down at your local electrical store for a reasonable price.

In September CASA is introducing new regulations around the use of RPAdrone-transparentS that make it easier for everyone to fly a RPAS. http://bit.ly/1sNxnt4 These consumer type RPAS will become more prevalent not only in the hobbyist field but also in the commercial field.

Esri is strategically placed to take advantage of this growing market. Recently released Drone2Map for ArcGIS (http://www.esri.com/products/drone2map) takes geolocated images from RPAS and creates professional imagery products for visualisation and analysis in ArcGIS.

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Image Tips in ArcMap

So you’ve loaded your image into ArcMap and the image displays incorrect colour or there is no data values around the outside of the image that is masking crucial features in your map. How can you quick rectify these annoyances? Well this is where the Image Analysis  window comes in handy.

Introduced in ArcMap 10.1 the  Image Analysis Window is accessed from the Display menu in ArcMap . The Image Analysis window supports the analysis and exploitation of image and raster data in ArcMap, with a collection of commonly used display capabilities, processes, and measurement tools. Essentially all your image needs in one place.

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Viewing Imagery in a different light

Imagery is the most commonly requested basemap of all the Esri base maps available. It provides the spatial context for your authoritative data that vector base maps cannot. Many questions can be easily answered by visually inspecting the imagery, for example how far is that tree away from the power line? or is that a new swimming pool that does not have a building permit?

There is though more to imagery though than visually inspecting in the Red, Green and Blue visual spectrum. Many of today’s satellites capture information in the Yellow, Near Infrared and Far Infrared portions of the electromagnetic spectrum. In fact the latest World View satellite has 16 bands. So how can this extra analytical data be accessed in a web service?

Image services provide an underutilised feature called functions. These are algorithms that can be applied to an image service on-the-fly to reveal hidden information in the imagery. When an image service published, it is not just the visible band that can be published but all bands from a satellite image can be made available. In its simplest form a function can swap these bands being used to display. For example from Red, Green, Blue to Infrared, Red, Green. Another common analysis is Vegetation health through an NDVI analysis. The difference in chlorophyll reluctance and absorbance of plants in the Infrared and Red portion of the spectrum.  The best part about using functions is that they are only calculated on the portion of image shown on the screen at the resolution displayed and no new image is created, just an interpretation of the image, all performed server side on-the-fly and then sent to the client. There are some very good examples on the Amazon Landsat 8 demonstrator site found at http://www.esri.com/landing-pages/software/landsat/unlock-earths-secrets

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LiDAR. Some thoughts on your acquisition.

ArcGIS supports LiDAR! It supports both XYZ  and LAS files. It can read and display these formats as point clouds or surfaces, in both 3D and 2D. These can be viewed in ArcMap, ArcScene, ArcGIS Pro and as elevation services through ArcGIS for Server. But this is common knowledge right? ArcGIS has been able to do this since 9.3 and we all knew that right?

Well I thought this was the case. Often though it is not. Many people are today just starting to investigate the best tools for LiDAR exploitation not realising the capabilities of the ArcGIS Platform and the wealth of knowledge available to support their investigation. If you want a good place to start take a look at this web page What is LiDAR data?.

But let’s take a step back from the tools right now and ask yourself  for what purpose do I want LiDAR data? Do I want it for flood modelling, DEM creation, building extraction or power line detection.  Do I want to just differentiate between ground and non-ground or do I need it classified into buildings, trees, ground and water? The reasons for asking these questions  is that the answers will dictate the order you place for LiDAR.

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Image services on the web

In my previous blogs I have described how to make imagery available in both image and maps services and how you may then consume these services in cloud image processing analytics. But what  about the actual image storage.

We know that imagery from ground up is always big! Everything about an image represents volumes and capacity. If you want to create image services and host them on your own infrastructure then you need to ensure that you have suitable attached storage but server storage is expensive and can be prohibitive.

Now we have all heard of cloud computing, how about cloud storage. Many of us would have  seen by now the new cloud storage solutions Dropbox, OneDrive or Box. Can I put my imagery here? Well not really as ArcGIS for Server cannot reference these storage and the storage required for imagery would get expensive. Amazon and Microsoft do provide cheap storage options in the S3 disks and Azure Blobs. These are ideal storage mechanisms for imagery as they are relatively cheap and imagery is relatively static. Even better we can configure cloud servers to read this imagery and serve it fast!

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