Kodo Millet PPT made by Ghanshyam bairwa college of Agriculture kumher bhara...
using query with MI
1. Lab 10: Spatial Queries
You have been asked to determine what census tract that each parcel
Property is contained.
How will you find the tract number for each parcel property &
display on a map using MapInfo?
In this lesson, you will learn how to ask questions/ query multiple data
layers when the only relationship between the layers is spatial.
You will learn what spatial operators : within, contain, intersect
You will also learn what a buffer is, how to create and how to use the
spatial operators with a buffer.
2. To create a Spatial SQL to answer:
Which parcels are within contaminated soil?
Spatial SQL in MapInfo
Select File> Open Table Select parcel & contaminated soil table.
Then:
1 Select Query
2 Select SQL Select
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2
(Continued on next slide)
3. Continued- Spatial SQL-Which parcels are within contaminated soil?
Answer is parcels
shaded orange
2 Select the tables using tables button
3 Move cursor to where condition box, select
columns button- select file. Obj
Select Operators button- select within
Select columns button- select file.obj
4 Select Verify
5 Select OK
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5. The order of tables can change
the spatial SQL result.
If contaminated soil table listed
first, it is the base table & the
output of the SQL is one
contaminated soil record (polygon).
If parcel table listed first,
it is the base table & the
output of the SQL is many
parcel records (polygons)
Spatial SQL
6. Example: Buffering selected polygons at a constant distance in MapInfo & having the buffer result in
one buffer for each object:
Select File>Open Table select table to buffer; In layer control- 1 make the cosmetic layer be Editable
2 Select OK
Buffer result
(3 buffer polygons)
3 Select objects to buffer on map using arrow select
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4 Select Objects
5 Select Buffer
6 Type Radius value &
select units feet or miles
select smoothness value
select 1 buffer or multiple
7 Select OK
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7. Example: Buffering selected polygons at a constant distance in MapInfo & having the buffer result in
one buffer of all objects
Buffer result
(1 buffer polygon)
8. You are now ready to begin MapInfo Exercise- Lab 10
Spatial Queries. The main objectives are:
• To ask questions or query data layers using:
Query> SQL Select Menu using operators of
within, contain, & intersect
• To create a buffer and using spatial operators, determine
if features from one layer are within or intersect features
from another layer
• Begin exercise- lab 10