Tagged Questions

Raster is a data format consisting of regular grids of values, usually stored in an image-like format.

learn more… | top users | synonyms (1)

8
votes
3answers
513 views

How to extract breaklines from a given DEM?

Breaklines are very useful for describing a terrain - for example to build an exact TIN. My question is, how to extract these breaklines from a given DEM? I calculated the curvature (vertical) - ...
1
vote
2answers
1k views

What might cause invalid syntax from ArcPy with Raster Calculator and Multiple Rasters?

I am having trouble for writing script in Python (ArcGIS 10.1). The task is generally divide each raster by 100. I have many of these raster files.... So what I've done is the following: from ...
3
votes
0answers
458 views

Weighted Average of several raster “zones”

thanks for the visit! Suppose I have two rasters, A and B. I want to determine the value of a certain "zone" in raster A by taking the weighted average of several other zones from raster B, that ...
1
vote
0answers
188 views

ArcGIS opposite to pivot table

fellow GIS-ers :)! I've been trying to find a tool to do the opposite to what the "pivot table" tool does but I dont thin there is any tools for that. I have a raster data set derived from Landsat ...
2
votes
1answer
267 views

Nearest Neighbor Focal Statistics and Map Algebra

I would like to use a nearest-neighbor type analysis to iterate over a raster. The nearest neighbor analysis will give a cell value of 1 IF AND ONLY IF the cell being analyzed has a cell value larger ...
3
votes
1answer
90 views

Location for floorplan

Is there an application / service where I can put my floorplan of a building en 'position' it on the right place on the earth? (The buildings location). I found TileMill an application where I can ...
2
votes
1answer
2k views

What are the units of the calculated area from a raster in decimal degree

I'm trying to calculate area for a raster file which contains 2 layers (0 for unsuitable habitat and 1 for suitable). It's been calculated successfully but I don't know what is the unit of the ...
5
votes
1answer
341 views

Georeferencing a jpeg in QGIS but the scale is way off

I've gone through the really helpful walk-through(s) of how to georeference a jpeg in order to make it a layer, but after inputting the coordinates (either by typing in actual coordinates or clicking ...
6
votes
1answer
383 views

ModelBuilder: How to extract data by date, export to separate tables and interpolate tables to rasters

I've been using ArcGIS for a couple years, but when it comes to model builder I've only worked with very simple models. I'm hoping someone that is much smarter than myself can help me in building a ...
3
votes
2answers
352 views

What causes RuntimeError: ERROR 010240 saving after CellStatistics?

I am having trouble saving outputs from CellStatistics but only when I run it on a list of rasters. This was working on python 26 but not 27. I know this example is nonsense, but: env.workspace = ...
2
votes
1answer
300 views

Raster as Attribute Field Error

I'm using Arc 10.1. I am creating a parcel inventory where I would like to have a photo of the property attached as an attribute and view-able with an HTML popup. I have a polygon feature class built ...
6
votes
1answer
230 views

How to create points around edge of viewshed results?

Is there a tool or module, or multiple tools, in ArcGIS that will allow you to automate the creation of points around the outer edges of a viewshed? What I am trying to do is gather data about the ...
2
votes
2answers
345 views

Can Geoserver return the raster value of a lat/lon point

I have a GeoTIFF published by Geoserver 2.2 and being used by Leaflet via WMS. How can I get Geoserver to return the raster value at a lat/long point? I'm guessing it has to do with using WCS, but ...
4
votes
2answers
1k views

How to Merge Raster Datasets of Different Resolutions?

I have two DEMs in .tif format and I am looking to merge the two. The main problem with merging these are that they are different resolutions (one is 10m and one is ~20m). Also, another problem with ...
3
votes
1answer
1k views

How to import QGIS Raster into PostGIS

I have created a IDW heatmap using QGIS 1.8.0 and need to import the raster into PostGIS 2.0.1. QGIS saves the raster layer as a .asc file. How do you import the raster into PostGIS as a Raster? What ...
2
votes
1answer
462 views

MrSid => GeoTiff

I have a MrSid file that I would like to convert to a GeoTiff. Is there a way to do this on a Mac running Mountain Lion? I know it can be done on Windows and Linux using the LizardTech command line ...
2
votes
2answers
741 views

R Raster package: write NetCDF with time dimension

I am writing a rasterbrick with multiple layers to a netcdf file using the raster package in R: writeRaster(gridfile, "Data", "CDF", overwrite=TRUE, ...
1
vote
1answer
73 views

MapInfo displays a JP2 raster weirdly - why?

We have some JP2 files created with FME 2013. They work just fine in ArcGIS, MapModeller and QGIS. But when viewing it in MapInfo (11.5) we get what looks rather like a 60's drug trip. Zooming in ...
1
vote
0answers
262 views

Reclassifying a raster based on values in another raster

I am attempting to create a new raster based on the values of two rasters I have already created. I am using ArcGIS 10.1 Raster1 is an area with my true values. Raster2 was created by reclassifying ...
1
vote
0answers
32 views

Rasterlayer divide

i´m new to qgis at all. I´m a blender user and found that beautiful NZ heightmaps at koordinates.com wich are CC 3.0 and free to use. I want to use this maps for heightmap displacement if i can ...
5
votes
1answer
455 views

Copy and Paste symbology in Raster?

I am trying to figure it out how can I take a preserved color from a raster I already set up before and then apply the colormap to a new raster file? Here are the details of what occurred: Before ...
1
vote
1answer
281 views

R: data.frame to raster object error

I have a data.frame consisting of a points with an associated continuos value and their X,Y coordinates. Altough it's not stored anywhere it's projection is a Lambert conformal conic. I think this is ...
3
votes
1answer
58 views

Problem Joining FAA raster charts

I am new to GIS and I am trying to place the North and South Salt Lake City aeronautical charts in QGIS. The problem I'm having is that there is a black section where the two charts should touch. Am I ...
4
votes
2answers
249 views

How to extract values from intersection of different size buffers with raster?

I have a polygon shape with buffers. However, the buffers are of different size from 4m radius to 15m. In total I have 7 different buffers. I have a landcover raster and I would like to extract ...
1
vote
2answers
1k views

“Extract by Mask” changing raster pixel values…or not?

I am using ArcMap 10.0 and am confused by my Extract by Mask output rasters. I hope to eliminate the black background from three Landsat ER Mapper images so that I can mosaic them. Originally I ...
3
votes
1answer
410 views

Extract multi values to point error

I am trying to extract values from my rasters : slope, aspect, landcover etc. for my animals group locations. I used Spatial analyst>Extract multi values to points but when I look in my attribute ...
2
votes
1answer
292 views

Create a subset of a dataset with a specific grid size in ArcGIS using Data Management Tool

I am wondering how you can create a subset of a dataset that is a specific grid size (in pixels) using the Clip tool within the Data Management Tool box for raster data. I was trying to find a hint ...
1
vote
1answer
137 views

Difference in raster size using raster2pgsql

I use the PostGIS-build-in raster2pgsql to load SAGA-raster into the db. I tried to grid them into 100x100-tiles, just as seen in the code: /usr/lib/postgresql/9.2/bin/raster2pgsql -s 32632 -a -F ...
6
votes
1answer
196 views

Assigning costs to a road network : use raster or vector?

I have a road network in a PostGis database (db_routing). In another database (db_environment), I have some spatial features of the surrounding environment (trees as points and water bodies as ...
1
vote
1answer
229 views

How to set min and max value for stretchType: esriRasterStretch_PercentMinimumMaximum

How can I set the min and max values for the stretch type "Percent Clip" in arcobjects? It's possible to set the Stretch type: rasterStretch.StretchType = ...
3
votes
2answers
2k views

How to reclassify a float raster?

I have three rasters which represent distance (in metres) from certain things (bus stops, parks, libraries). I would like to reclassify these rasters so that they get integer values based on the ...
2
votes
0answers
104 views

Raster area (QGIS) problem explained

I would like to know the area that each value in a raster has... The raster I have has values from 2-15 and I would like to know the area that each value is occupaying within my polygon... Thanks! I ...
0
votes
0answers
38 views

Why are areas of raster and polygon after digitization not matching? [duplicate]

I have followed the answer given in this question:How to calculate the area of rasters in QGIS? I vectorized and calculated the area using geometry columns but I a faced a strange problem. When I ...
3
votes
3answers
1k views

How to Export Raster with same classification colors seen in ArcMap?

I have a single band raster, but i like to export it with the same colors as in Arcmap. Any help please.
0
votes
1answer
215 views

GMT raster (*.tiff + *.pgw) in epsg4326 shifts few kms (4326-900913-3857 problem?) [duplicate]

This seems to be an old problem with an already known solution (ie. "...stop using 900913 and start using 3857..."), but not sure whether this problem is about software versions, the raster itself or ...
0
votes
2answers
616 views

Grass 7 / ArcGIS 9.3 - tiff to raster

Again a Grass 7 question. I have the output of a modelling run as matlab file, which I can export as tiff and load as geotiff. OK - now can I extract the data/convert this tiff into a raster proper? ...
1
vote
1answer
79 views

Grass7 - r.regression.multi and new raster

I am on the learning curve with Grass7. I managed to make r.regression.multi work, but there is one thing that would be of high interest for me: it is possible to create a new raster showing the ...
10
votes
1answer
613 views

What is some theory on the number of GCP when georeferencing?

Just wondering, is it always better to have more than 3 GCPs? Should the GCPs be spread out evenly? Where can I find some general resources on the theory of this? Other than trial an error, which ...
3
votes
1answer
31k views

What is the difference between Vector and Raster data models? [duplicate]

From: http://support.esri.com/en/knowledgebase/GISDictionary/term/vector%20data%20model vector data model: [data models] A representation of the world using points, lines, and polygons. Vector ...
1
vote
1answer
373 views

Problem to clip a raster with a shapefile

I need to clip a rasterlayer with a vector layer. When I try this, the following error appears: **ERROR 1: Attempt to create 0x0 dataset is illegal,sizes must be larger than zero.** What am I ...
3
votes
1answer
288 views

raster tile - find the correct tile for a given coordinate

I have a large raster map which I loaded into postgis with 1000x1000 meter tiles... the corresponding table has about 200 rows, each row representing a tile. I want to get the raster value for a ...
5
votes
3answers
922 views

What is a simple binary raster storage format which ArcGIS can read?

I have a C++ program that manipulates raster digital elevation models. I have been using ArcGrid ASCII format for results. It is simple to code and gets the job done, but it necessitates a decimal ...
14
votes
3answers
397 views

Which CRS would you use to georeference historical world maps?

Which CRS would you recommend to georeference historical world maps like the ones in the London Geographical Institute - The Peoples Atlas - 1920, e.g. The map displays a lat/lon grid which I would ...
3
votes
1answer
120 views

Differences in raster extents in gdalinfo, SAGA & Quantum after resampling

I recently resampled a raster file using SAGA's Resampling module. The aim was to widen the extent of the new raster to two decimal places, where the original raster has three decimal places. The ...
2
votes
2answers
955 views

Reducing the resolution of a huge raster

I'm not much of a GIS user, but I've got a big ascii file that I'm trying to convert into a lat long data x1 y1 d1 x1 y2 d2 x1 y3 d3 x2 y1 d4 ... etc format, so that I ...
0
votes
1answer
123 views

Algorithm to merge adjacent raster datasets

I am trying to figure out how to merge adjacent raster datasets. Is there any clear algorithms (may be a pseudo code)?
0
votes
0answers
91 views

Display raster outlines

I guess mine is a very simple task, however I don't know how to solve it. I m trying to display the outlines of a raster created from a polygon shp. What I would like to come up with is an image where ...
3
votes
0answers
247 views

How to create raster attribute table to a raster data using gdal python?

I classified a remote sensing data and saved it as a raster using Gdal python. I want to create a raster attribute table for this classified result.. my classified raster has five classes with ...
2
votes
0answers
35 views

Automatically discard nodata area of raster [duplicate]

Given a raster with an overly large nodata surround, how can I automatically discard the surround? Said another way: how does one shrink the raster extent to only occupy the area containing values? I ...
2
votes
1answer
100 views

Can TimeManager animate a large number of rasters in QGIS?

I understand that as of a year ago, the TimeManager plugin was not intended to handle more than a handfull of rasters. This post is in blind hope that this has changed! I'm trying to create a map ...