0
votes
0answers
13 views

Determine changes in land cover of isolated features over time?

I have a a study area of 2 Landsat scenes from 2013 which were classified for a specific natural community, and these areas have been isolated and extracted and digitized into vectors so that they can ...
1
vote
2answers
25 views

polygon to raster - not all polygons rasterized

I have a building footprint shapefile (polygons) that I want to convert to a raster. I use the Polygon to Raster tool, and specify a cell size by importing from another raster (which is 24m x 30m). ...
0
votes
1answer
41 views

How do I overcome this problem of converting a raster layer to polygon form?

I am trying to convert a raster layer of U.S. climatic regions into polygon format using ArcMap 9.3 under Windows XP. The original data are to be found at the following address: Koppen Climate ...
0
votes
1answer
21 views

gdal_rasterize : getting area not in or touching polygon (options -at and -i)

I would like to capture the area that is not in a polygon (option -i) and that doesn't touch that polygon. gdal_rasterize -at will return the polygon + edges, but gdal_rasterize -at -i will not ...
3
votes
1answer
54 views

Changing raster cells values inside of a polygon to the closest cells just outside the polygon!

I have been wrestling with this for a while and couldn't find out how I can do this. I want each cell of a raster inside of a polygon boundary to have the value of the closest cell just outside of the ...
1
vote
1answer
57 views

Step-by-step: How do I extract Raster values from Polygon overlay with Q-GIS or R?

I am writing my master thesis at the moment and am having the exact same problem as user Curley in this question: I first need to overlay a Corine 2006 raster with a polygon layer (2638 polygons). ...
0
votes
1answer
37 views

Extracting info on polygons from underlaying raster layers

In ArcGIS 10.1, I have two layers: 1) raster of Topographic Wetness Index 2) vector layer of polygons representing soil types I am wondering how to accomplish what I am after, that is to get ...
3
votes
2answers
64 views

“Levelling” elevation data coinciding with polygon?

I have a shapefile containing building geometries (polygons) and a elevation dataset. The elevation data doesn't perfectly match the buildings. I want to "flatten" the elevation data so that ...
-1
votes
0answers
31 views

what is the math behind rasterization? Doubt [duplicate]

In Figure 4 you can see how the overlap is not complete (marked with circles). What I would like to know which algorithm that QGIS uses the rasterization? What is your standard? Is there a percentage ...
0
votes
1answer
35 views

How to select a specific area (in a polygon form) determined by some value range in a raster band?

For example, I want create a vector layer with polygons that represents all areas where the elevation is between 500 and 600. Someone has any idea to help me? I'm using PyQgis 2.2.
0
votes
1answer
60 views

Setting a value on a raster where a polygon intersects cells

I reviewed all of the supposed 'answers' and I just do not see that they really answer my question. Mostly because the ones I'm reading are setting values either inside or outside a boundary. So let ...
2
votes
0answers
35 views

Does converting polygon to raster generate more accurate results from the Zonal Statistics in Arcgis 10.2

I have heard the following for Arcgis 9.1 and wonder whether it is still an issue in Arcgis 10.2. If so, should I convert the polygon into raster before dissolve or convert the dissolved polygon ...
1
vote
1answer
41 views

Eliminate 0 Values From Raster

Arcgis 10.2 I currently have a raster file that I want to turn into a set of polygons. This will help me to create specific buffers around certain points. The extent of my values are 0, and 1. When I ...
0
votes
1answer
42 views

Associate points with polygon QGIS 2.2

I want to associate a point layer with a polygon layer so that I can do zonal statistics. In the image below, the polygon layer represents roughly the metro area of a certain city. The point ...
4
votes
2answers
122 views

Converting shapefile to raster: Character attributes

I've got a shapefile that I would like to convert into a raster, but the trick is that the attribute I want a raster version of is character data. I'm familiar with geoprocessing using GDAL (in the ...
0
votes
2answers
44 views

Polygon Data to Fit Raster

I'm working with an NHD Flowline of streams and rivers in NC, and I'm trying to only retain the ones in the raster. I tried to convert to the raster to a polygon and was going to clip them, but in the ...
2
votes
1answer
152 views

QGIS - How can I convert a raster file to a vector file without making same value cells into one polygon?

How can I convert a raster file to a vector file without making same value cells into one polygon? In the attached image, the values "2124", "2269", "2321", "2634", and "2920" are the polygons ...
2
votes
3answers
554 views

Clip a raster using a shapefile into multiple rasters?

I have a raster file representing a large area and a shapefile of 30 polygons representing watersheds. I would like to clip the raster with the shapefile to create 30 rasters representing each ...
1
vote
1answer
71 views

Converting a raster to a polygon

I need to convert a raster into a polygon, and I ran into "Error 000863: Invalid GP Data Type" After searching, I saw this solution online. Basically I needed to convert the float raster to an ...
1
vote
2answers
144 views

How to change raster cell values within a polygon using QGIS GUI?

I would like to know how to change the values of raster cells which are within a polygon, leaving all cell values outside the polygon unchanged. I would like to subtract 1.5m from each raster cell ...
2
votes
3answers
331 views

How to get count of non-NA raster cells within polygon using R

I've been running into all sorts of issues using ArcGIS ZonalStats and thought R could be a great way. Saying that I'm fairly new to R, but got a coding background. The situation is that I have ...
1
vote
1answer
175 views

How to extracting raster data to multiple polygons?

I have a reclassified raster dataset (10 classes) and I want to find out the area of each class contained within multiple (hundreds-to-thousands) polygons. I have all the polygons in the same ...
0
votes
0answers
23 views

calculate proportion of polygon greater then 40 degrees in grid cell QGIS

I would like to calculate the proportion of greater then 40 degree slope within my polygon grid cells. I have a Slope Raster layer for my given area and have a polygon that overlays this raster ...
0
votes
1answer
46 views

ArcGIS10 Highest point via polygon features

I am using ArcGIS 10.0 with 3D Analyst, Spatial Analyst and Military Analyst. I feel like I am halfway to solving a problem but do not seem able to completely solve it. I have a polygon shapefile ...
1
vote
1answer
75 views

Raster Data to Polygon [closed]

I need to "translate" raster information to a set of polygons. The raster to polygon tool will not work. I created a fishnet with the same resolution of the raster and converted it to polygons. I now ...
0
votes
0answers
25 views

calculating mean and standard deviation for raster values using whole pixels within a polygon [duplicate]

i have a raster image and a corresponding shape file. i would like to calculate the statistics of the values within polygons which have a common attribute but only using pixels which are fully ...
0
votes
0answers
18 views

Classifying raster pixels using polygons [duplicate]

I am trying to retrace some steps from an experiment I conducted a couple weeks ago. To make a long story short: I didn't think it was the right result so I didn't write down my procedures. I think ...
1
vote
1answer
240 views

Polygon to raster without losing any polygons

I'm trying to convert polygons to raster. But the output raster dataset doesn't have polygons which went into as input data. I need all the date in the attribute to follow with to the raster dataset ...
1
vote
1answer
350 views

identify percentage of raster cells within a polygon

As per the title I want to determine the population inside multiple polygons according to different land use zoning (High Residential, Low Residential, National Parks etc) that's in raster format. ...
1
vote
0answers
225 views

How to Smooth Polygons after converting DEM using Raster to Polygon?

I have a DEM SRTM that I classify using Spatial Analyst Tools > Reclass > Reclassify. The result is box shaped so I go to Layer Properties > Display and choose cubic convolution. The result is ...
2
votes
1answer
400 views

combine raster and polygon values in R

My question is similar to this one Get Raster Values from a Polygon Overlay in Opensource GIS Solutions but I think I need another step. I have a polygon layer of ecoregions which I brought into R ...
1
vote
1answer
132 views

Aggregating a raster to fit a polygon grid

I am working at the scale of 10 square km grid cells for the UK, and have a polygon layer of the Ordnance Survey 10k grid cells in ArcGIS. I have another layer of the human footprint index, also for ...
4
votes
1answer
226 views

Raster to vector with gaps in Landsat ETM

I need to find size of water area from a raster (jpg) using QGIS 1.8.0-Lisboa. The raster is a Landsat image with gaps of data in it. I used Polygonize, but the output file shows wrong polygon size ...
1
vote
1answer
224 views

How to convert a shapefile polygon to raster in C#

Does anybody know a way to convert a polygon (vector) in a shapefile to raster data WITHOUT using ArcGIS Explorer Desktop? Is there a way to do this 'progmatically' in C# (WPF with ArcGIS runtime ...
3
votes
1answer
158 views

Polygon to Raster is taking longer in script than in arcmap

I have a large dataset that I am working with. Basically I have a table with 900,000 records that I join to a geodatabase feature layer, then convert that to a raster. This process takes a total of ...
6
votes
2answers
236 views

Breaking apart a polygon layer by unique values, creating many new layers

I have a large dataset of habitat information that I need to calculate distances from animal locations to the closest polygon of each habitat type. The way to do this, that I understand, would be to ...
3
votes
2answers
238 views

Determine density or cover from a raster layer that has been clipped by a polygon

I am a very new GIS user using ArcMap 10. I have a raster layer of tree canopy that I have clipped so that the layer is in a polygon that is a circle with a 2km radius. I have done this for four ...
5
votes
2answers
1k views

How to sum pixel values within a polygon zone in QGIS?

I have two layers: a raster layer and a vector layer (polygon). I can see the values of the raster pixels but I don't know how to combine them with information from the polygon layer. More ...
2
votes
1answer
190 views

Obtain normalized raster average per polygon?

I have a raster that contains percentages of total forest killed plus a polygon layer that defines different zones. My goal is to find a good statistical representative that describes the forest ...
4
votes
5answers
681 views

Python loop Polygon to raster not working

I want to convert a large number of different shp polygons to raster in ArcGIS 10.1, using an existing field column "class" for the new raster classes. I am not very fluent in python but I thought ...
2
votes
1answer
235 views

joining a table from zonal statistics as table with a layer, problem with reserved names

I have a raster file (percentage of total forest killed) and a shapefile with polygons (municipalities). I thought as a first step I would like to find out which municipality shows the greatest ...
7
votes
3answers
2k views

Using polygons to apply unique value to all raster cells within those polygons?

In ArcGIS 9.3, I have a raster file that I would like to "mask" with polygons, giving a single value to all the raster cells that overlap the polygons. How can I do this? Here's a screen shot, ...
2
votes
3answers
829 views

Zonal Statistics as table creates output but some are Null

Here is my newest issue: I have temperature as a raster file and different ecoregions of a province as polygons. What I want to do is calculate the mean temperature per ecoregion. I succeeded in ...
3
votes
2answers
2k views

Polygon to Raster Tool Problem

I am trying to create a raster data set from county level polygon data for the US. I have successfully created one raster from a dataset, but when attempting another, it does not work. I am ...
2
votes
1answer
186 views

how to create an outline polygon (footprint) from raster data with postgis?

how can I create a polygon, containing the actual outlines (aka footprint) of a raster file with postgis? I just need the outlines of the data containing parts of the raster. ST_PixelAsPolygon ...
5
votes
2answers
766 views

How to enclose clustered points with polygon?

I have a raster with forest (1), no forest (2) data. "1" is represent single/few trees and there is gaps between them. I want to create a polygon around these trees to a forest map. It is not a dense ...
1
vote
1answer
161 views

gdal_rasterize -at function still won't capture covered pixels properly

I'm currently using the gdal_rasterize tool in bash. My code looks like this: gdal_rasterize -l $(basename $file .shp) -burn 1 -a_nodata 0 -te -180 -90 180 90 -tr 0.1 0.01 -at -ot Byte $file ...
5
votes
1answer
666 views

Export selected raster cells to polygon

I have selected certain values in a raster (roughly 1000 cells), and would like to export them to be able to create a polygon. Converting it to points first then to polygons does not work. Can anyone ...
5
votes
1answer
595 views

Identify Polygons on raster image

I have OS street view mapping as raster images. Is it possible (without the obvious of tracing each dwelling) to identify all polygons on each tile. To clarify, My ultimate aim is to produce a ...
19
votes
3answers
1k views

Packing Polygons within polygon

I have a Boolean raster. In the grey areas of the raster I would like to fit a given size polygon within a contiguous extent. Basically, I have an irregular polygon, and i would like to "fit" a ...