0
votes
0answers
52 views

I am getting NULL values when I use “point sampling tool”?

I am trying to extract values from a raster using a point shapefile, but I am getting NULL values. I think that NULL values are obtained because the Coordinate Reference System (CRS) are not the same ...
7
votes
2answers
316 views

How to extract vectors from map using QGIS?

I am trying to extract building footprints from a raster map (as shown in the example below). Please note that the maps are out of copyright, have been scanned and georectified by a library and have ...
1
vote
1answer
22 views

RasterStack extract() for duplicated dates

I have a a Large RasterStack of temperatures and a 10570 points in a Large SpatialPointsDataFrame and I'm using extract() to assign the temperatures to each point in R. ...
0
votes
0answers
51 views

Los Angeles Public Parking Lot Polygons?

So, I'm looking for some relevant data to incorporate into my map, and one of them is public parking polygons. Is there such a .shp file with these data?
3
votes
0answers
79 views

Creating a new raster based on pixel value of original raster using raster calculator but new layer is not evident

I am trying to create a new raster based on a current raster (w001001 - NVIS) which has one paletted band, with palette values ranging from 1 to 29, with each palette/value representing a vegetation ...
0
votes
1answer
149 views

Merging Multiple Paths

Alright, I'm going to start by using Google Earth terminology because that's where the original need for a solution came up. I have multiple paths (54) that I want to merge into a single path. ...
2
votes
2answers
316 views

Create polygon of buildings from Quickbird images in QGIS

I have Quickbird/Ikonos/GeoEye image and want to extract all the buildings from the image as an independent layer in QGIS. How can i achieve that?
4
votes
3answers
2k views

How to extract raster values and create new raster in Qgis?

I want to extract certain values of a raster image in order to create a new raster which then should only contain the extracted/chosen values. How to do this in QGis?
5
votes
2answers
382 views

Extract certain area of contours/satellite images

I have 2 satellite images (jpeg2000 format) and 2 xyz-files from the same area. I am trying to extract certain region from the area including contour lines and the satellite image in order to import ...
4
votes
0answers
153 views

What open source solution would work best for auto extracting features from satellite images? [duplicate]

Possible Duplicate: Feature Extraction - Land cover I have been looking for an open source solution which would allow me to define a region (or collection of images) and extract features ...
6
votes
1answer
755 views

Can I specify a point and get all features within a certain radius of this point?

I have recently shifted to QGIS from ArcGIS and am looking for some help/pointers with the following: Does QGIS have a method by which I can specify a lat-lon coordinate (or a utm x,y coordinates, ...