Use the `raster` tag for questions about raster datasets. A "grid" is a regular partition of a spatial domain into congruent nonoverlapping pieces or a set of lines forming a grid-like pattern (aka "graticule").

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2
votes
1answer
2k views

Convert X Y Pixels to Easting Northing

Hopefully someone can help. I'm trying to find out what the formula would be to convert the X, Y of an image to the Easting and Northing coordinates. I've downloaded some of the raster maps from OS ...
0
votes
2answers
293 views

QGIS regular points around each polygon in a layer (vs ALL polygons)

I have a number of buffered points (some where polygons intersect & are dissolved. I'd like to create regular spaced points grid around EACH polygon -- not ALL polygons. When I do Vector -> ...
6
votes
2answers
4k views

Create a polygon layer from point data

I'm currently using QGIS 1.8.0 I would like to create a polygon layer from a point dataset, where the size of the polygons relates to the resolution of the grid reference. The ultimate aim would be ...
2
votes
1answer
169 views

How extract data from a SNODAS file

I'm trying to extract data from a raster file from "Snow Data Assimilation System (SNODAS)" and convert it to a MMQGIS (plugin) grid layer (Hexagon) with QGIS. This raster file stores the snow depth ...
0
votes
0answers
935 views

Lat/long grid in QGIS using WGS84 projected layers [duplicate]

I'm using QGIS to project some shapes that are in WGS84 coordinate system. I want to add a grid to the map in the map composer but when I try to do it the degrees don't show up. I have tried to do ...
2
votes
1answer
526 views

How to export vector features to grid using proxy and WFS protocol?

I am trying to export vector features (current view) as a grid, something like: http://workshops.opengeo.org/geoext/wfs/grid.html so far layer features are not being retrieved.. I got empty grid in ...
1
vote
1answer
634 views

How to convert a polygon to a grid of polygons using QGIS?

For example, the city of Rotterdam represented as a hexagonal grid.
3
votes
1answer
75 views

How to modify height model values outside of road network

I have a height model of a quite big area saved in Esri ASCII grid files and a road network of this same area in a shapefile. I'd like to convert every height model value outside the road network to ...
0
votes
1answer
120 views

Why are grid and scalebar measures 1mm too long in a 1:10000 print?

I used qgis 1.8 to compose a map from the WMS-service of the Belgian NGI. I added a scalebar and grid to it. When I measure it by hand, the distance between the longitudelines is 101mm instead of ...
0
votes
0answers
148 views

SAGA grid VRT, file how to apply a LUT?

I've created a heap of saga grid files for some hydro survey work. I'm looking at a way to read these into a mapguide raster/grid layer, I'm able to load up the grids using a vrt file, I can't figure ...
-1
votes
1answer
356 views

how to make grid cells by point data

I have a csv data. the X, and Y columns show bottom left corner of each grid. It is supposed to show as grid square, but it shows points. what is the problem? and is there any way I can make cell ...
3
votes
0answers
111 views

How to view Esri GRID format file in wxpython file browse window? [closed]

I'm trying to browse for all kinds of vector and raster data using a filebrowsebutton. The problem is I don't know how to let the browse window see the Esri GRID files (which contains a folder and a ...
11
votes
4answers
1k views

How can I generate irregular grid containing minimum n points?

Given a large (~ 1 million) sample of unevenly distributed points - is it possible to generate irregular grid (in size, but could also be irregular in shape if that is possible?) that will contain ...
6
votes
1answer
2k views

Grid and Graticule in QGIS Print Composer

Is there any other option to display DMS grid and graticule in QGIS Print Composer, since there is no plugins available yet?
3
votes
2answers
477 views

How to display DMS in QGIS print composer?

Can we display degrees, minutes, seconds in QGIS Print Composer window instead of decimal degrees? Is there any plugins available for that? Thank you very much.
2
votes
1answer
1k views

How to create a grid constrained within a polygon in QGIS?

In QGIS I have created an irregularly shaped polygon. I can create a grid based on the maximum extents of the polygon via Vector>Research Tools>Vector Grid. However, what if I need the grid to ...
4
votes
1answer
459 views

How to specify coordinate reference system (CRS) for scalebar that is different to project CRS?

Is it possible to specify a coordinate reference system (CRS) for the scalebar that is different to the project CRS? For example, my project CRS uses geographic coordinates (lat/long), the reason ...
2
votes
2answers
613 views

How to create a valid global polygon grid in PostGIS?

I want to create a grid spawning the whole globe. The grid is used to measure a density value by counting the number of certain spatial objects in each grid cell. To create the grid, I have created ...
8
votes
3answers
1k views

Creating regularly spaced, defined # of points within polygon in QGIS

I used the research tool "Regular Points" to produce a certain number of points within a polygon, but it forms a rectangular grid of points rather than only within the shape of the polygon. Since I ...
5
votes
2answers
409 views

Optimum grid/pixel size for interpolating rainfall and temperature

I have a set monthly rainfall and temperature data within an approximately 100 x 100 km study area. The sampling points are unevenly distributed within the study area. Based on a paper by Janis et. ...
0
votes
2answers
301 views

How to implement a spatial query on polygon data for a specific point?

I have vector data fed into a database which returns a report at province level upon querying. This is implemented in a web tool. I want to add an extra functionality at point level, where I can ...
4
votes
1answer
336 views

Sub-dividing a polygon into smaller polygons

In OpenStreetMap data, some large areas are tagged with a residential=yes tag. Actually within this large polygon there are multiple smaller (rectangular) houses (which are actually not drawn as yet). ...
3
votes
4answers
3k views

How to create a grid whose vertex coordinates are shown on an attribute table in Arcmap?

I have a specific area to study. Before starting on my field work, I have to create a 310m X 310m grid of the area. Later on I have to get the coordinates of each point of the grid in an attribute ...
1
vote
0answers
365 views

how to get ascii grid from corine land use data?

I'm trying to get ascii grid with land use data (by one parameter - CODE_00). Afterwards I will import it into simulation tool. But I cannot figure out how to convert ascii grid from shapefile. ...
3
votes
1answer
1k views

How can I add a grid (from projection MTM8) on my layers

I need to add a grid on a map I created with my own layers and GPS data. How can i do this? I know how to do it in Arcgis, but not in QuantumGIS. Can you help me?
3
votes
1answer
230 views

Dividing a geographic region

I have a certain geographic region defined by the bottom left and top right coordinates. How can I divide this region into areas of 20x20km. I mean in practial the shape of the earth is not flat it's ...
3
votes
2answers
2k views

How to convert GRIB-1 to GRIB-2?

I need to get data for my database from some GRIB files (binary), I downloaded wgrib2, which can export GRIB-2 files to .csv and csv is very suitable for me, but some GRIB files are GRIB-1, so I used ...
3
votes
2answers
1k views

Conversion of GRIB and NetCDF to my database

. I have downloaded "High Resolution Initial Conditions" climate forecast data for one day, it was in extension .tar.gz so I extracted it in my local directory and I get the files like in the ...
3
votes
1answer
140 views

Method to compute and visualize the closest set of facilities from OSM data

I want to use OSM to extract a set of facilities e.g. school, park, hospital inside a given region. from that, transform the area in grid and for each cell in a grid compute its score mixing the ...
1
vote
1answer
1k views

Generating Map Tiles for MGRS Grid Graticule

I'm possibly a bit out of my league here, but ready to get my hands dirty. I want to generate map tiles for a MGRS grid graticule similar to http://tiles.mapbox.com/mapbox/map/afghanistan-mgrs. I ...
3
votes
2answers
408 views

TIFF, Grid, FGDB Grid, etc. - what performs better in ArcScene animation?

I am creating a flyover animation in ArcScene and I would like my surface raster to be rendered in full resolution (an exported function raster dataset - a blend of shaded relief and high resolution ...
9
votes
3answers
3k views

Divide a complex shape file into a grid

I have a decently detailed shapefile with polygon/multipolygon features (the file is about 500mb). It's actually a shapefile of the entire world, with the features representing coastlines. I need to ...
5
votes
3answers
371 views

In what data format should I export a (lat,long,alt) or (x,y,z) grid to be compatible with the largest number of GIS software?

I am new to GIS and developing an application that generates a 3D grid with (latitude, longitude, elevation) or (x, y, z) metric triplets, and I would like to add an exporting feature that ensures ...
3
votes
2answers
1k views

From point to Grid of polygones or polylines

Is it possible to reconstruct a grid of polygones or polylines from the centroids? I am looking for a arcGIS tool or script that will allow me to reconstruct a grid of polygons or polylines from ...
1
vote
1answer
152 views

What are the strengthes and flaws of using grid-cell analysis in GIS with fishnet?

As I mentioned in the title, I'm going to use grid-cell analysis. what are the strengthe and weakness??
7
votes
1answer
2k views

How to convert point data into a gridded dataframe for histogram analysis?

I am very new at using GIS data and only modestly experienced with R. I've been reading about how to analyze spatial data using the spatial-analyst.net PDF book, so I'm not completely lost, but I ...
0
votes
1answer
11k views

How to make a grid with a certain spacing between lines along X and Y axis?

We are doing the research about applying remote sensed data on hydro logical model . After delineating, the river basin from DEM data using Argis9.3, We have to map the remote sensed data derived from ...
4
votes
2answers
1k views

How to read this GRIB data [closed]

on this open FTP server (ftp://ftpdatos.aemet.es/modelos_numericos/hirlam005_peninsula/) you can find HIRLAM models from the Spanish meteorological service. The documentation in the LEEME files (in ...
7
votes
1answer
1k views

Coordinate grid display on a rotated map

I have a series of maps that require me to rotate my data frame within my layout screen (north "rarely" points up in these maps). I ONLY want to show east coordinates on the top/bottom and ONLY north ...
5
votes
4answers
218 views

What to call these types of grids?

In a GIS application I'm developing there's an option to show two types of grids. First is a standard lat/lon grid. Second is a crosshair with marks and distances in four directions away from the ...
-1
votes
1answer
108 views

How to locate 'symbols' by means of grid cells in MapInfo?

I am new to Mapinfo and GIS in general, but I have a new job in a company that works with maps and GPS and now I am being trained. My question, and I have looked a lot and I couldn't find anything, ...
0
votes
1answer
349 views

Arcmap 10 corner label measured grid

I am using the corner label feature in Arcmap 10. This allows you to set the "Numer of principal digits" and the "Number of base digits". What do these properties refer to?
6
votes
1answer
981 views

ArcGIS 10: Adjust custom grid intervals based on map scale?

I am preparing a pmf which includes a custom grid overlay. To clarify: a custom grid overlay is marginalia, not a feature class with geometry (so a scale dependecy inside a layer won't work). The ...
1
vote
0answers
121 views

Arcobjects - Properties Grid

Does anybody know a way, in VBA, to change the grid interval? For example: if my layout´s scale is 1:2000, my grid will have 200 meters interval and my layout´s scale is 1:5000, my grid will have 500 ...
2
votes
2answers
2k views

Converting xyz batch to ESRI grid format using XYZ2GRID 2.1 - batch problems

I am trying to use Min-Lang Huang's XYZ2GRID2.1-Batch program downloaded from ArcScripts and I keep getting the error C:\users\public...........xyz Error-Object required Does anyone know what the ...
1
vote
3answers
442 views

How to infinitely extend MapInfo grid layer?

We use a semitransparent grid layer (.mig file) to show 'hotspot' intensity in MapBasic (MapInfo. Because the grid is just a rectangle, this looks ugly. See for instance: . Now MapInfo allows grid ...
6
votes
6answers
708 views

How can I convert a DEM into areas of “flatness”, with an arbitrary fill/cut to area ratio?

I want to find areas of relative "flatness" in a DEM. How can I find flat areas? I want to find a neighbourhood of contiguous cells that have an elevation variance that is within a certain ...
8
votes
3answers
2k views

Ordnance Survey grids - download or generate?

Does anyone know a source from which to download vector UK Ordnance Survey grids at varying resolutions? Or failing that, a tool that can create an OS grid at a specified resolution? There are plenty ...