Hot answers tagged erdasimagine
7
There is no way to get floor heights from a lidar pointcloud. Lidar is captured by bouncing lasers off the groundsurface and measuring the bounced back pulses. Therefore there is no way for the lasers to 'see' through the roof of a building and return a floor height.
However, a solution to this may be to classify your las point cloud into ground and non ...
4
Though I am not able to understand the difference between the standard
deviation output and the percentage output and what is the
significance of using one over the other?
Those refer to the threshold used to decide whether there has been any change between two images. For percentage change, it uses a symmetric relative difference formula to
...
3
There is nothing built into the software that can solve differential equations. I am assuming that your values are derived from spatial data or you would be posting this on another site. Your best bet (if you are tied to one of these software packages) is to write some code in ArcPy that pulls in your values and does the math. This Python library will help ...
3
From the USGS FAQ: the blue band is useful for "Bathymetric mapping, distinguishing soil from vegetation and deciduous from coniferous vegetation".
It's my experience that you get better results by using band combination, however.
3
I would recommend calculating soil moisture indices from Landsat TM bands. MTRI has an interesting article on creating soil moisture index (SMI) from Landsat TM 5. Also, I would recommend exploring soil moisture estimates using TM band 6 (Thermal IR). Attached is a good tutorial on calculating indices from Landsat TM bands using ArcGIS 9.x (as you ...
2
you can check out Qgis Sextante Toolbox in plugins repository. it has lots of geoprocessing alagorithm in it.
SEXTANTE is a spatial data analysis library and a powerful
geoprocessing framework.The main aim of SEXTANTE is to provide a
platform for the easy implementation, deployment and usage of rich
geoprocessing functionality. It currently ...
2
You can open the raster image as a GDALDataset :
poDataset = (GDALDataset *) GDALOpen( pszFilename, GA_ReadOnly );
Then get the raster band containing the color codes with :
GDALRasterBand *poBand;
poBand = poDataset->GetRasterBand( i ); where "i" represents the raster band id.
Then iterate over the raster band pixels and read each pixel color code value ...
2
There are several good sources including the following:
WELD
WELD generates 30-meter composites of Landsat 7 Enhanced Thematic
Mapper Plus (ETM+) terrain corrected (Level 1T) mosaics at weekly,
monthly, seasonal and annual periods for the conterminous United
States (CONUS) and Alaska. These mosaics provide consistent data that
can be used to ...
1
Here are the steps on how to do it in ArcGIS (Extract from online help)
In ArcMap, click the Add Data button. Navigate to the location of the HDF file. Click the file and click Add.
The Subdataset Selection dialog box opens. Click a single subdataset to add. Optionally, press and hold the CTRL key to select more than one.
If you choose more than one item, ...
1
I'm not a user of ERDAS software, but i'm wondering if you could use any of these datasets to help you distinguish particular features in the coastal environment you're working on?
I've found the GSHHG dataset a useful tool in the past.
1
I would download the data again. Sometimes large downloads get corrupted. I have downloaded this exact data so I know that it is fine. You should not be getting any errors while unzipping. The ige file is just an indexing file to address large files that exceed 32bit addressing space. The file that you work with is the img.
I would recommend subsetting the ...
1
In ArcGIS you can clip the raster(img file) using a graphic. If you have a polygon layer that you want to use as the clip boundary right click on it and convert feature to graphic. Make sure the resulting graphic is selected and then right click on the raster. You should be able to export and use the graphic to clip. If its not part of the export on raster ...
1
This post has several sources of Landsat data, most notably the USGS EarthExplorer website.
If you need anything later than autumn 2010 you'll have to wait until about mid-May when the USGS makes imagery from the LDCM publicly available.
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