Tag Info

Hot answers tagged

18

Aerial photos are continuous data. Each pixel represents the response of a region of a sensor to light directed at it and as that light varies, the response varies continuously. The result is usually discretized (often into 255 or 256) categories, but that doesn't change the nature of the data. Therefore you want to interpolate rather than using ...


12

Landsat is available back to the 80s, it may overlap the dates of your project, excepting of course the 1950s. edcsns17.cr.usgs.gov/NewEarthExplorer/ will let you easily browse the archive, once you apply for a username. With that in mind you could potentially get a series of three satellite scenes, two of which tie in with the aerial imagery. For ...


11

You need to tile the image and add overviews so that the whole image is never read into memory at the same time. GeoServer provides an image pyramid datastore for this purpose. I wrote these notes describing how I set this up on my machine. The key step is to use GDAL to build the pyramid using the following command: mkdir bmpyramid gdal_retile.py -v -r ...


9

GDAL has a wonderful file format called VRT, which is an XML wrapper around one or more raster files. One feature of VRTs is their ability to encode square convolution kernels for any given band. It does involve playing around with XML in a text editor (or programatically), but if you're already used to the GDAL tools, it shouldn't be too hard. To ...


6

UK permits 192 Private Companies [eg EDF], Government Agencies including Police and even the British Broadcasting Corporation [BBC] In the last two years the CAA has required anyone who wants to fly a small UAV in British airspace to apply for permission. The aircraft must weigh less than 20kg and operators have to abide by certain rules. These ...


6

Your fire hydrants will have a very unique spectral signature, therefore I would use supervised maximum likelihood classification to classify your raster. An alternative is to run an ISODATA algorithm for an unsupervised approach. Try the following (partial) workflow: Open Iso Cluster Unsupervised Classification in ArcGIS Enter ALL 3 bands (i.e. R, G, B) ...


5

MapQuest Open Aerial Tiles Global Coverage (higher zoom level in the US) MapQuest Open Aerial Tile URL example: Terms of Use The MapQuest Open Tiles are available for use for free under the following conditions: http://developer.mapquest.com/web/products/open/map#terms MapQuest Open Aerial Tile URL example: ...


5

I doubt your process "gets caught in a loop", I think it will just take a long time to complete as your rasters are actually quite large. Those "small rasters totally less than 100mb" are roughly 2Gb uncompressed, each. The layer properties you included in your question show that particular raster has dimensions of 36702 cols, 14147 rows and 4 bands with ...


4

are you in touch with the Nepal community? http://www.osmnepal.org They have quite a lot of projects going on, particularly in the field of Disaster Risk Reduction. Apparently, they have access to higher-resolution images as well: http://tasks.hotosm.org/job/190 (look under the workflow tab) List of curren tasks: http://tasks.hotosm.org/#all/nepal hope ...


4

Here a "work in progress" answer... We are currently developing bundle block adjustment support in the orthorectification chain of GRASS GIS 7. It will be usable for aerial photos and UAV imagery. A prototype will hopefully be available in early 2014. If you are interested and willing to test, please contact me directly. It is an enormous amount of work, so ...


4

For topic 1. QGIS uses GDAL as an QgsRasterdataProvider. So the capabilities of reading and writing a raster format is implemented by the GDAL lib. You can find supported a format under the following link http://www.gdal.org/formats_list.html. The command gdal-config --formats gives you an overview which format stuff is build into your lib or edition. What ...


4

For topic 2: Here is an longer investigation of JP2, because I was also interested, to use a more efficient compression. And the result IMO is: Within GDAL/QGIS (as a QgsRastrerDataProvider) you can't combine proper jpeg2000 compression and fast caching options like tile sets and block structures in a simple way. Normally I perfer GeoTiff for Raster-DB's, ...


4

Based on huckfinn answers, few other comments and together with my findings: Winning format is JPEG2000 (why and which version is mentioned below Why not others) Why not others: JPEG Size limitation both data size and dimensions (4GB and 65500x65500) no (internal) pyramids possibility = bigger the image the longer it takes to display it when pan/zoom ...


4

All of the specific answers I can come up with would have likely already occurred to you as a photographer. A low distortion lens with a shorter focal length (based on your prospective altitude). High shutter speed to minimize motion/vibration impacts. Interval and speed are something of a function of your flight plan and altitude - I don't know if there ...


3

ImageMagick supports: Large image support: read, process, or write mega-, giga-, or tera-pixel image sizes. command --line will the most efficient way to do this: (via -layers method) merge As 'flatten' method but merging all the given image layers to create a new layer image just large enough to hold all the image without clipping or extra ...


3

If you are looking to reproject an aerial image in QGIS you will need to make sure you have the GDAL Tools plugin installed (which you can find in the Plugin Manager). When it is installed you will see the Raster Tab in the main frame. In the Raster tab you will see Projects. If you aerial has an existing projection, use the GDALWARP (Reprojection) tool. ...


3

I lack the "reputation" to Comment so... If radiometric analysis is going to be performed on the aerial photos then it should be done prior to resampling/projecting. Otherwise you will almost certainly introduce unintended bias into the final product. As per blord-castillo's helpful comment above. If the proximate and final uses of the aerials are for ...


3

Use your GDAL's Fusion Table driver to load your shapefiles into Google Fusion Tables. The GFT developer docs are pretty self explanatory. You can then use standard php code (even in your shared hosting environment) to write your webapp. If you want more functionality, you are going to have to move to something where you have more control of your ...


2

Sorry for answering to myself. In case, if someone wonder how to mosaic color map image (1 band) with RGB image (3 bands). I figured, that simplest method will be to convert color map into RGB (possible in Arc with Copy Raster tool) and then mosaic them. Thanks.


2

Have you looked at using the Composite Bands tool in arctoolbox?


2

I'm afraid yo can not import a folder of tiles recursively. In gvSIG 2 that will be quite easy to perform. Right now you can load any number of files from a particular folder with the typical "add data" dialog.


2

What is your area of interest? You can download and use the NAIP imagery from 2011/2012 which is 1m as long as you can host your own service and cache/tile yourself. If you need outside the US, then Digital-Globe/GeoEye is going to be your prime vendor.


2

Nationally, you could check the list of programs at http://www.ndop.gov/maintenance.html or http://pubs.usgs.gov/fs/2009/3055/pdf/FS2009-3055.pdf. At least 2 programs that fly leaf-off are listed. You will probably find more current and higher-resolution options if you check with each state's natural resources, forestry, or emergency management agencies, ...


2

Israel has recently (2007) amended the civil aviation laws to include private and commercial use of UAVs, as well as certification and permits under the Civil Aviation Authority - CAA. Due to the nature of things, civil and commercial use of UAVs up until then was done under the Israeli Air Force. CAA say there are currently 15 civilian companies operating ...


2

The Mosaic to new raster function is what you need. Don't add an extension for the output raster, which would make it an ESRI GRID, which can be clipped as you like.


2

So if I assume the following variables: x = camera sensor x size y = camera sensor y size f = focal length h = height above ground And I am looking for: ay = photo y ground distance ax = photo x ground distance Would these formulas work? making sure that I compare the proper units to the proper units. (f/h)*x = ax (f/h)*y = ay Does this make ...


2

TileMill from MapBox is designed to be code free as possible. There are some impressive tiles in the gallery https://www.mapbox.com/tilemill/gallery/#kkaefer.iceland There are 4 steps: Import Data Style your data (time consuming) Add interactivity Export Map (MBtiles, PNG, SVG) Documentation https://www.mapbox.com/tilemill/docs/


2

Please check out http://www.klokantech.com/maptiler/ very good software to create tiles from images.


2

You wont be able to find a plug and play solution, but there are many options if you have the time. Here's a guy to look into, he's got a blog where he plays with Bundler, PMVS2 and all the other nice software and puts it together in a way that makes it reasonably easy to run: http://www.visual-experiments.com/demos/sfmtoolkit/ These guys have a trial, and ...



Only top voted, non community-wiki answers of a minimum length are eligible